Is the 2000 Watt Society Sustainable in Switzerland?

Recently a debate has arisen here at ETH Zurich centering on the question whether the envisaged "2000 Watt Society" is inevitable. Why shouldn't we be allowed to use more energy? Wouldn't it be more important to limit greenhouse gas emissions? A report about the new energy strategy of ETH Zurich was published in the Oil Drum in May 2008.

In this presentation, we discuss whether the 2000 Watt Society is at all sustainable, and if so, what it will take to keep energy supply at that level after the end of ample and cheap fossil fuels. What are the implications of energy deprivation to our society? Can we stave off famine? How can we maximize our chances of getting through the emerging world-wide crisis relatively unscathed? What are the pitfalls in designing and implementing a strategy that helps us achieve these goals? How much time have we got left?

Predictions are notoriously difficult, especially when they concern the future. So, how sure can we be that our predictions are correct? How can we convince the public at large that there is a real and present danger looming in the not too distant future, despite the fact that at this point in time few signs of any problems are noticeable yet here in Switzerland, and particularly, as the crude oil price has recently fallen to one fourth of the value it was at in early July of last year?

This paper is based on a talk presented by the author at the Zurich Physics Colloquium a few days ago. The talk is available on the net both as a Powerpoint presentation and as a podcast.

A Sankey Diagram for Switzerland

Let us start by analyzing the current energy situation here in Switzerland. This is best represented by a so-called "Sankey" (energy flow) diagram:

Fig.1: Sankey diagram of Switzerland - source: Dr. Michael Piot, Swiss Federal Office of Energy

The diagram shows on the left hand side the produced and procured (imported) sources of energy. Different types of energy are marked in different colors. The brown energy at the top represents wood. The wood is grown in Switzerland. The red energy below represents crude oil that is being imported and refined in Switzerland. The most prominent orange energy represents refined oil imported into the country. The yellow energy denotes gas. Gas is also imported. The green energy denotes nuclear fuel. Although we have currently five nuclear power stations in Switzerland to convert the nuclear fuel to electricity, the fuel rods themselves are being imported. The blue bar represents water power. It is available locally and is converted to hydro-electric power in turbines here in Switzerland. The thin dark blue energy source at the bottom represents everything else: solar, wind, geothermal. Together they make up only about 1% of the total energy mix currently consumed in Switzerland.

On the right hand side, the diagram shows the consumed energy. At the top, the private homes are being depicted. The dominant form of energy consumed in households is heating oil, as most private homes in Switzerland are still being heated by central oil heating systems. Hence if we decide to save electricity by exchanging our light bulbs for fluorescent lamps, we do relatively little to alleviate the peak oil problem, even if we save substantial amounts of electricity. Below are shown industrial buildings. These consume much less energy, and they have already been fairly well optimized. Not much can be done to improve their energy consumption further. Below, the diagram shows the service sector including all government buildings, schools, hospitals, etc. They are similar to the private homes in their energy consumption pattern. Yet below is the transportation sector. This is the largest consumer of fossil fuels in Switzerland. The narrow blue line represents the electricity consumed by our railway system. The unconnected bottom block shows the energy consumption by agricultural enterprises. It is important to have this information, as we must produce food for our population. This by itself turns out to be highly problematic.

Per Capita Power Consumption

Let us add all of the sources of produced and procured energy together and divide this number by the total population of Switzerland. The data are summarized in Fig.2.

Fig.2: Total energy production/procurement in Switzerland

Switzerland produces and procures a total of 1.12 EJ of energy per year. Of this total amount, 20.2% are produced locally, whereas 79.8% are imported. Dividing this energy by the number of seconds in a year, we obtain 35.576 GJ/sec = 35.576 GW of consumed power. Dividing this number by the total population of 7.85 million people, we obtain a total per capita consumption of 4.53 kW.

This number is considerably lower than what BP list as Swiss power consumption in their annual statistical energy review. The BP statistics are referenced frequently, because this is the most comprehensive collection of energy data publicly available today. Where does the discrepancy come from? BP is an oil company, and as such, they don't consider water power as a "primary" source of energy. To them, only stuff that is dug out of the ground is "primary" energy. Hence they are asking themselves, how much oil Switzerland would have to buy from them and burn in order to produce as much electricity as we are getting out of our water turbines. They rate the efficiency of fossil fuel burning electric power plants at 33%, and therefore assign a "handicap" to Switzerland by bumping the "primary" energy numbers for our water power up by a factor of three. The so modified statistics are shown in Fig.3.

Fig.3: "Corrected" energy production/procurement in Switzerland

So, now Switzerland is consuming 1.38 EJ/yr, corresponding to 43.88 GW in total, or 5.5887 kW per capita.

These numbers are still somewhat skewed, because neither the Swiss Federal Office of Energy (SFOE) nor BP consider material flows other than those of primary energy carriers. Switzerland imports lots of goods from foreign countries (including food) that consume energy for their production. This is called grey energy, and grey energy has not been included so far in the energy statistics. Whereas Switzerland is an export nation in monetary terms (we earn more money by selling stuff and services to other countries than we spend on buying stuff and services from them), we are an import nation in terms of grey energy, i.e., we are importing considerably more grey energy than we export.

There are no hard numbers available to quantify the amounts of surplus grey energy imported, but it is generally accepted that this corresponds to roughly 1/3 of the accounted energy. Thus adding the grey energy into the energy balance, Switzerland consumes between 7-8 kW of power per capita (using BP accounting methods).

How Much Energy Is Our "Fair Share"?

Let us try to answer that question in a round-about way. To this end, we shall first look at the so-called ecological footprint, produced for the Swiss Government by the Global Footprint Network:

Fig.4: Ecological footprint – source: Living Planet Report 2006

The graph shows on the vertical axis the amount of land area used per capita to support the life style of the average inhabitant in different countries, and on the horizontal axis the so-called Human Development Index (HDI), an index measuring the living standard in these countries.

The countries of this planet follow a banana-shaped curve starting on the lower left with people, mostly from sub-Saharan African nations, consuming very few resources while living under dismal conditions, and ending on the upper right with the U.S. and the U.A.E., two countries whose inhabitants consume exorbitant amounts of resources while leading very good lives.

Switzerland uses 5.1 hectares per person and consumes 5.5 kW of power per capita. The U.S. uses 9.6 hectares per person and consumes 9.8 kW of power per capita. The two measures are almost proportional to each other, i.e., we can mark the vertical axis in kW of consumed power instead of hectares of used land, and the curve will remain almost unchanged.

Using hectares as a measure of consumption has the advantage that we can add up the entire usable surface of our planet and divide it by world population. In this way, we obtain an available land area of 1.8 hectares per person. We are currently using on average 2.2 hectares per person, i.e., we cannot continue to use as much as we currently do in a sustainable fashion.

In order to allow developing nations to improve their living standards, we must allow them to use up more of the world's resources. We cannot do so in a sustainable fashion, unless the rich nations give up some of their own usage.

Our goal should be to bring all countries into the orange area at the lower right corner of Fig.4, where they can lead a life of acceptable comfort, while not charging the resources of our planet in an unsustainable fashion. Currently, there is only one country in that area: Cuba. Thus, if President Obama is serious about his commitment to sustainability, then his slogan should no longer be "Ich bin ein Berliner," but rather "Soy un Cubano."

If Switzerland wants to bring its ecological footprint down to 1.8 hectares per person, it needs to reduce its energy consumption to roughly 2 kW per capita. This is how the idea of the 2000 Watt Society was first created.

Unfortunately, Switzerland may under those conditions not be able to maintain the same living standard that Cuba currently enjoys, because Cuba is a tropical island that can grow food year round, whereas Switzerland needs to either spend real energy to store food for the winter months or spend grey energy to import food during those months, and in all likelihood, Switzerland will need to do both.

How Much Power Can Switzerland Consume in a Sustainable Manner?

Let us now analyze how much power Switzerland can consume in a sustainable fashion. To this end, we shall now look at the consumption side of the Sankey diagram. This is summarized in Fig.5.

Fig.5: Energy consumption in Switzerland

We consume considerably less energy than we produce and procure because of the losses in energy conversion. Our current nuclear power plants have an efficiency of only 30%, and also hydro-electric power was charged with an (artificial) efficiency factor of 33%.

In Fig.6, I displayed the numbers of Fig.5 graphically.

Fig.6: Energy consumption in Switzerland today and tomorrow

A large majority of the Swiss people are not in favor of nuclear power. The licenses of our five current nuclear power plants will expire within the next 20 years. Unless we replace them by new nuclear power stations, and at least until now, there is no will to do so, this power will simply go away.

The oil and the gas will no longer be available in significant amounts, thus we cannot rely on having those still at our disposal by 2050. Assuming that we aggressively increase all alternative types of energy (solar, wind, geothermal) by a factor of ten, which may be difficult but doable, we will have only 2 kW per capita available by 2050.

Hence the 2000 Watt Society makes sense also from an entirely different angle: not as a lower limit of how much we may consume with a good conscience, but rather as an upper limit of how much will be at our disposal after the availability of cheap and ample fossil fuels has drawn to a close.

When Will We Run Out of Oil?

The United States Geological Survey (USGS) predicted in 1998 that world oil production would peak around 2003:

Fig.7: Peak oil prediction – source: L. Magoon, U.S. Geological Survey

The measurement data end in 1997, because the graph is already more than 10 years old. An updated graph of a similar nature depicting both oil and gas together is shown in Fig.8.

Fig.8: Peak oil and gas – source: C. Campbell, ASPO Ireland

Colin Campbell predicts oil and gas together to peak by 2010. These predictions are based on a method developed more than 50 years ago by M. King Hubbert. Hubbert predicted that world oil would peak around the turn of the century.

The technique is very simple. Each individual oil and gas deposit exhibits similar production patterns. First the production increases over time, then it peaks, and thereafter, the production decreases rapidly. All of these deposits together must, as a consequence of the law of large numbers, follow essentially a Gaussian distribution. The integral of the bell-shaped Gaussian distribution (the error function) can be approximated by a logistic curve:

dP/dt = a • P - b • P2

where P(t) denotes the total production up to time t.

We can use past measurement data of P, and perform a least squares fit to determine the best values of the unknown parameters a and b. This can be done either using global data directly, or for different regions of the globe separately. The final value:

Pmax = a / b

represents the total amount of oil (and/or gas) that will ever be produced.

I applied this method to the last 22 years of global oil production. The results of the curve fitting effort are shown in Fig.9.

Fig.9: Curve fitting past oil production data. The measurement data are plotted in black as curve (a); the Gaussian (Hubbert) prediction is shown in blue as curve (b); a constant exploration model is depicted in red as curve (c); and a continued exponential growth model is given in green as curve (d). Explorations (c) and (d) come to an end, when the total oil according to Hubbert's method has been produced.

BP tell us that, according to their best estimates, we still have enough conventional oil for 40 years. The prediction is made under the assumption of a continued constant exploration. This corresponds to the model (c) of Fig.9. Their statement is thus in fairly good agreement with the Hubbert model, as the two areas between the red and the blue curve are of equal sizes.

Luckily, BP's assumption of continued constant exploration won't hold. The law of large numbers gets in the way. The low-hanging fruit has already been harvested. Fig.10 shows new oil discoveries over time, in accordance with USGS.

Fig.10: New oil discoveries – source: L. Magoon, U.S. Geological Survey

The new oil discoveries follow quite well an exponential decay curve. This is how BP are able to estimate the remaining not yet discovered oil.

It is very fortunate that BP won't be able to keep the production up until the end, because an abrupt termination of oil production after another forty years would mean the end of the world as we know it. Exponential decay is bad enough, but an abrupt termination is equivalent to driving a car into a brick wall at 100 miles per hour. The ride is beautiful while it lasts, but the end is not pretty.

BP calculated their reserve estimates at a sales price of $80/barrel. If the price is much lower, then many of the remaining deposits cannot be exploited economically. If it is higher, then more oil deposits will become economically exploitable. Thus, we may actually have more oil available than currently predicted by BP, but not much more, as I shall demonstrate. In either case, the year of the peak doesn't change by much. Peak oil is not going to occur in the distant future. It is happening now.

What About the Oil Price?

Before peak oil, we are living in a buyers' market. Different oil producers compete for customers, and only those who offer the best prices can sell their product. The price of oil is dictated by production cost, and oil is consequently cheap.

After peak oil, we are living in a sellers' market. Different customers vie for oil, and only those who are willing and able to offer the highest price will be able to buy. The price of oil is dictated by market forces, and oil is consequently expensive.

Last summer, we came into the vicinity of peak oil, and consequently, the price of crude was rising rapidly. In the mean time, the world economy tanked for reasons that I don't wish to explore. Some people believe that the economy tanked because of high oil prices, but the reason is actually irrelevant to the analysis.

As the economy turned sour, fewer goods were produced, and consequently, less oil was needed. The demand for oil shrank by a few percentage points, and this sufficed to drive the oil market back into pre-peak territory. Consequently, the oil price came down once more.

Yet, our fortune won't last. Because of the current low oil prices, several new oil projects have already been delayed, as these deposits cannot be exploited economically at a price of $50/barrel. This drives the oil supply down.

As soon as the economy will start to recover, the demand for oil will rise again, which will drive the oil market immediately back into post-peak territory. It may take a few more months or possibly a year for this to happen, but the low oil prices are not to stay.

As we move down the Hubbert curve, no reduction in demand due to a shrinking world economy can keep the oil price down.

We are still consuming oil at almost the maximum rate, and much more than what we are using now is simply not in the cards.

Even worse, as oil becomes a scarce commodity, the oil producing nations will satisfy their own needs first before they export. Consequently, the international oil trade will shrink even faster than oil production.

The Curse of Shrinking EROEI

Most of the cheap oil has already been produced. The remaining oil is more difficult to get at, and therefore, its production is more expensive. Yet, this is not only a question of price. It is also a question of energy consumed in the process of developing these deposits. We need to take into account the Energy Returned On Energy Invested (EROEI). Unfortunately, the EROEI of oil is shrinking rapidly.

Charlie Hall has compiled a list of EROEI values for different energy sources. It is reproduced here as Fig.11.

Fig.11: EROEI for different energy types – source: C. Hall, The Balloon Diagram and Your Future

U.S. domestic oil had an EROEI value of around 100 in the early years of oil exploration. You dug a hole somewhere in Pennsylvania, and the oil came gushing out. By 1970, the EROEI of U.S. domestic oil had already shrunk to a value of about 30. Oil imported into the U.S. today has an EROEI value of below 20.

As the EROEI shrinks to a value of 1, it no longer makes any sense to produce it irrespective of its price. Why would anyone want to burn one barrel of oil to produce one barrel of oil in return?

Charlie Hall estimates further that energy produced at an EROEI value of below 5 cannot support our society sustainably. The reasons for this claim will become clear in due course.

Notice that bio-fuels of the first generation (such as the bio-fuels produced from corn in the U.S. and those produced from sugar cane in Brazil), shown in the lower-left corner of the graph, have EROEI values in the vicinity of 1. The EROEI of U.S. bio-fuels is reduced by irrigation needs and by highly automated production involving large plantation machines that consume lots of diesel fuel. The EROEI of Brazilian bio-fuels is reduced by the need to destroy (burn) large areas of rain forest first followed by a rapid degradation of the land.

Second generation bio-fuels, especially those produced from algae, may have higher EROEI values, but it is too early to know already, where their EROEI will be. Also, just like in the case of the first generation bio-fuels, they cannot be produced in sufficiently large quantities to solve our energy problem. They may help, but they are no cure.

The Dynamics of Our Energy Economy

Charlie Hall plotted a series of Sankey diagrams depicting the dynamics of our energy economy. Fig.12a shows the situation in 1949.

Fig.12a: Energy and economy diagram for 1949 – Source: C. Hall, Economic Implications of Changing EROI Ratios

The economy is driven by several feedback loops. The black feedback loop at the bottom denotes the EROEI. Energy needs to be invested to produce more energy. By 1949, the EROEI is high, and therefore, the feedback is drawn as a relatively narrow vector.

The production of energy also costs money. This is shown by the dark blue feedback loop at the top. Money is also spent for maintaining the infrastructure, as shown in clear blue. Some money is furthermore invested in improving the infrastructure. This is shown in red as discretionary investment.

Some of the money generated by our economy is not re-invested but spent. Some money is spent on food. This is shown in clear brown. The remaining money is used for discretionary spending, such as flying to the Maldive islands on a vacation.

Fig.12b shows the same Sankey diagram for 2007.

Fig.12b: Energy and economy diagram for 2007 – Source: C. Hall, Economic Implications of Changing EROI Ratios

What has changed is that the EROEI of energy production has shrunk dramatically. Consequently, the black feedback loop is now much thicker. However, the overall economy has grown, and therefore, there is still a lot of money available for discretionary spending. We are in fact more wealthy than in 1949.

Fig.12c shows the same Sankey diagram as estimated by Hall for the year 2030.

Fig.12c: Energy and economy diagram for 2030 – Source: C. Hall, Economic Implications of Changing EROI Ratios

What has changed is that peak oil is now behind us. Consequently, the oil has become very expensive, and a much larger percentage of our wealth is required to acquire energy. Consequently, the dark blue feedback loop is now much thicker as well. Therefore, less money is now available for discretionary spending, and we have all become poorer again.

Fig.12d shows the same Sankey diagram, now projected to the year 2050.

Fig.12d: Energy and economy diagram for 2050 – Source: C. Hall, Economic Implications of Changing EROI Ratios

The EROEI of energy has shrunk further, and the cost of energy has increased some more. The black and the dark blue feedback loops now consume all of our resources that aren't needed to simply stay alive. The amount available for discretionary spending has shrunk to zero.

As the amount available for discretionary spending turns negative, the infrastructure falls apart, as we can no longer maintain it. Consequently, we can no longer feed the entire population, and the die-off begins.

Hall's model may actually be a bit conservative, as it doesn't take into account the uneven distribution of wealth in different regions of the planet. Comparing Asian Americans in California with African Americans in Mississippi, we notice a difference in life expectancy of 15 years. African Americans in the Southeast of the U.S. die 15 years younger on average simply because of economic conditions.

For this reason, it must be feared that the die-off will begin much earlier than 2050 in some regions of the world.

What Does This Mean For Switzerland?

Switzerland is in a relatively comfortable position as far as electricity is concerned. We produce almost none of our electricity from fossil fuels. Hence I do not expect our grid to disintegrate permanently any time soon. Brownouts and blackouts may become more frequent than they are now, but they will not lead to a complete breakdown of the grid.

Yet, we nevertheless import 70-80% of our overall energy (depending on the accounting method), and most of our imported energy is based in fossil fuels: oil and gas. Therefore, we will have to learn to live on considerably less energy than we have available today.

What Can Switzerland Do?

The most cost-effective way of countering energy shortage is through energy savings.

Switzerland should aggressively push for minergy housing. Neighboring regions, such as Vorarlberg, for example, have done so in recent years much more effectively than Switzerland. In Vorarlberg, almost all new houses are now built to minergy standard. The government pushes this technology aggressively and offers subsidies to new home builders to make it more attractive economically to built to minergy standard. In contrast, only about 20% of new houses in Switzerland are built to minergy standard. The Swiss government needs to do more, much more in fact, to push energy-efficient homes.

Switzerland needs to push for more fuel-efficient lighter vehicles. The weight of the average passenger car in Switzerland has risen in the last 15 years from 1200 kg to 1500 kg. Quite clearly, the Swiss government has failed to educate the population about the bad consequences of wasting energy on equipment that is unnecessary and doesn't even improve the quality of life in a significant way.

Most governments spend currently millions and millions of Dollars trying to reactivate their stalling economies. Investing in energy infrastructure, e.g. through government incentives directed at measures that promote energy savings, may do so much more effectively than throwing money into the fangs of money-hungry investment bankers.

Energy saving measures alone can reduce the Swiss energy consumption by 40% without sacrificing the life style of its inhabitants to a significant extent.

Switzerland should furthermore invest in infrastructure for a more robust grid, thereby reducing the risk of repeated brownouts and blackouts.

More incentives should be offered to let people use electricity during off-peak hours.

A refrigerator or freezer doesn't need to consume electricity on a 24/7 basis. It would make sense to install a smart sensor between a refrigerator and the wall outlet that senses instability in the grid and temporarily switches off the device whenever the grid becomes more unstable.

The same holds for electric heat pumps. They can also be temporarily switched off. Smart controllers can optimize electricity consumption by heat pumps to occur primarily during off-peak hours.

Switzerland should invest aggressively in solar and wind power. These alternative sources of energy won't be able to replace the energy currently imported in the form of fossil fuels in their entirety, but every bit helps. We'll need all that we can get.

Switzerland needs one more generation of nuclear power stations. Switzerland should pursue the construction of one new nuclear power station at every one of the five current locations to pick up the load when the licenses expire for the old power stations. Otherwise the pressure will be large to keep the old power stations running beyond the time they can be used safely.

Nuclear power in its current form is not sustainable either. We'll also run out of uranium. Yet, new nuclear power stations will take some pressure off the energy situation by buying us more time to transition to sustainability.

Hopefully by the time the new nuclear power stations need to be shut down, we shall have come up with other sources of energy to pick up the remaining load. If we are lucky, we'll have these new sources of energy on-line even earlier, and in that case, we may be able to retire our nuclear power stations even before their licenses expire.

As we still have not solved the final nuclear waste storage problem, as we still don't know what to do with the used nuclear fuel rods, I recognize that I advocate adding a few more IOUs to an already large stack, but the alternative looks even worse.

Switzerland can't go it alone.

Switzerland currently imports 40% of its food. Switzerland cannot feed a population of close to 8 million people from food produced locally. Switzerland is in fact the worst of all European nations in this respect. We rely heavily on food imports beside from energy imports.

As the economic situation deteriorates, Switzerland's dependence will become more critical, as we won't have as many surplus financial resources available to ensure imports.

Durable agreements with the EU nations are therefore very important.

Switzerland is in a relatively comfortable position with respect to greenhouse gas emissions. The reason is that Switzerland uses hardly any coal at all. For this reason, our per capita CO2 emissions are about half of those produced by other Western European countries.

Yet, greenhouse gas emissions are a veritable problem, and Switzerland needs to contribute to its solution, primarily by helping developing nations to invest in cleaner technologies.


When I walk through the streets of Zurich and look into the windows of the shops, I don't notice any change yet. There is no shortage of anything. Energy is cheap and amply available. The inflation rate has come down. Unemployment hasn't picked up yet. It is still below 3%.

For this reason, I cannot blame the average Swiss for walking through life with blinders on. Life is good, they think. There isn't a worry in the world. Those who predict doom are just that: doomers. There is no reason to listen to them, let alone take them seriously.

With this article, I hope to wake some of my compatriots up from their sleeping-beauty slumber. Problems that lie ahead don't need to be obvious and visible in order to make them predictable.

Peak oil is taking place as I write. An immediate and inevitable effect of peak oil will be rapidly rising energy prices, and those are accompanied by a further downturn of the economy. This is going to happen irrespective of what we do.

Yet, this does not mean that we cannot prepare ourselves and thereby soften the impact of these events on the Swiss population. In fact, we should have started preparing much earlier, as we have known about these problems for more than 30 years already. The longer we wait, the more difficult and costly it will be to avert the worst. If we do nothing, we'll experience the full brunt of peak oil and its consequences, unmitigated and merciless.

I live in Luzern and have been following the increasing volume of the peak oil web movement and learning about the possible implications of this for a while now. I know for a fact that 95% of the 25 - 45 year old people I know, have absolutely no concept of even the phrase Peak Oil, let alone what this likely scenario may present in the very near coming years. I sincerely hope that public awareness can be quickly, and one hopes painlessly, raised to fire up the public and private actions necessary to even safeguard a level near to our current levels of energy and food consumption...

What awareness of some of the numbers you put forward gives us, is perhaps an urgent need for an open and public mapping of the rescources of the country. Both privately owned resources (such as food land, housing land, water springs etc.) and publicly owned resources (nuclear power, other power gereration, gas, hydro etc)..... so we know "what have we got here?" Surely a crucial question to be asked that only gives black and white answers rather than speculated guesses relying basically on the so called markets and the so called politicians to regulate the levels of our prosperity and our contributions to the system!

A more of a Recource Based Economy mentality needs to be taken in the approach to new projects and public resource decisions so as to improve the efficiency of the depletion of our resource base and also NOT to rely on good relationships with other neighbouring countries. I lived in Andorra for a while and if France and Spain decided something for Andorra, Andorra listened or starved.... If the borders were sealed or oil or gas or rubber or beef or fish or (insert your favourite dinner here) was no longer imported or was severley restricted, how would we get on? What would this do to other commodity prices if we are reliant solely on market speculation rather than solid numbers and what have we got here ?

Anyhow, I hope you have sent this to all the "news"papers in the public domain so everyone can have a good read on the train on the way may even get us all talking in the morning!

Finally, Thank you M. Cellier, for posting such a well written and thoughtfully link-referenced paper. A real eye opening piece. I hope it gets the attention it deserves in CH.

Regards, Tim Sutton, Luzern.

Thanks for your kind comments.

I agree with you wholeheartedly that most people here in Switzerland have no understanding whatsoever of what Peak Oil is and what it can and will do to us, and it's not for a lack of information out there, both on the web and even in the printed media. Some books on these issues are even available in German translation, such as Heinberg's The Party's Over.

Furthermore, due to the nature of exponential growth, many resources will peak almost simultaneously, i.e., within a few years or decades of each other. Problematic are food and fresh water, for example. Once again, Heinberg described this excellently in his book Peak Everything, which, as far as I am aware of, hasn't been translated into German yet.

It's more a question of mindset. The Swiss are socially highly conservative, and therefore inert. Problems that haven't bothered our parents and grandparents are of no concern to us either ... unless and until they hit us in the face, which hasn't happened yet as far as Peak Oil is concerned. They are certainly not going out of their way to explore issues that don't bother them directly. As far as they are concerned, electricity is coming out of the wall outlet, and food is coming from the Migros. That is good enough for them.

I haven't sent the article to any newspapers yet. For this, I would need to translate it to German first, which I haven't done yet. However, I am a member of ASPO Switzerland, and I have sent the article to its president, Daniele Ganser of the University of Basel, giving him the opportunity to forward it to all ASPO members if he so chooses. Of course, I know that I am reaching the wrong people with this, as ASPO members are already aware of Peak Oil.

Personally, I would send it to the papers as is :)

When Libya and CH had a tiff about Gaddaffi's son's behaviour and Libya temporarily cut off the supply last year, (really, did they?!! when?? haha) I was expecting instant outrage, queues at petrol stations, doubling of prices, but was still pumping normally, so everone just carried on... If that had been England there would have been riots...(not that this is preferable of course!) I thought surely this event would jolt CH into debate about how easy it is to have someone shut an import door and totally disrupt life. But no. Not yet....

I think you are right to also highlight several different simulataneous peaks. Food production increases are definitely not happening at the moment, due to droughts in many major food producing nations alone and I would also like to see figures on loans made to farmers (also for the US and UK) over the last 10 crop years compared to the last 12 months just to check they aren't having credit issues as well...

Water? lets not go there yet!!...Evian use over 7 litres of water to make a litre of water, never mind the other resources used to ship it everywhere!

So what would life be like if CH had to get by on it's own resources I wonder ?

Could you email me a pdf of the posted paper (as opposed to the ppoint)? I guess I could cut and paste but wouldn't want to be presumptious! I may just accidentally leave a copy on the train every now and again...

The PDF version is on the web. You can download it here.

Surely the parents and grandparents of many among the Swiss had to live through WWII or even WWI.
I don't know the figures for Swiss oil imports or CTL during WWII but I assume the decline was a lot more abrupt than peak oil is expected to be.
Rationing is not unheard of and there are (or used to be) injunctions to stockpile supplies in government-issued literature.

What about excessive trust in the government? That sounds like a possible issue with the peak oil message.

True enough. During WWII, Switzerland received very little imports (it did receive some coal from Germany), but the situation was quite different then in comparison with today.

Switzerland had during WWII about half as many inhabitants (4 million people instead of 8), it had twice as much arable land (much of it has meanwhile been paved over), and it had 3.5 times as many farmers (14% during WWII, 2% currently).

Switzerland managed to feed its population, but only barely. Executing the Anbauschlacht of the (later) Federal Councillor Wahlen, Switzerland slaughtered most of its farm animals and converted every piece of arable land into a potato field. Every able-bodied person had to help during the weekends with working the fields, and those without a job had to work the fields six days out of seven.

The rationing was severe, but thanks to the Anbauschlacht, Switzerland was able to feed every person living here in Switzerland a diet of 1800 calories per day.

Today, this would be impossible. Switzerland cannot feed its current population without food imports.

Simply building another generation of nuclear power plants doesn't address the problem of oil imports declining. And oil imports is where most of your energy use is, and most of your emissions.

As you note, peak oil is here. Since Switzerland does not participate in invasions of oil-producing countries, it will have a smaller piece of the dwindling supply. So whether you like it or not, you'll be burning less oil.

If you're going to be forced to burn less oil anyway, you may as well plan for it. Since you have no oil and a dwindling import of it in the future, but can generate electricity locally, obviously you must convert your transport to using electricity.

Switzerland had during WWII about half as many inhabitants (4 million people instead of 8), it had twice as much arable land (much of it has meanwhile been paved over)

In your many problems then lie your solutions to them. You can't simply make every car electric, since then you'll still be using too much energy. You need more efficient forms of transport. Make more of your transport mass electricity-using transport. This lets you get rid of many cars and reduce oil imports, you can tear up a lot of the paving and get more arable land.

The power generation, transport and food problems are all joined; we should join their solutions, too.

In your many problems then lie your solutions to them. You can't simply make every car electric, since then you'll still be using too much energy. You need more efficient forms of transport. Make more of your transport mass electricity-using transport. This lets you get rid of many cars and reduce oil imports, you can tear up a lot of the paving and get more arable land.

We have been doing much of that. Our public transportation system is excellent. We have the most dense electric train system in all of Europe, and its capacity is pretty much maxed out. On most routes, trains pass by every two to three minutes. You cannot pack them more densely without causing accidents.

All of our larger cities have local transportation systems based on electric trams and trolley buses. We don't have subway systems, because our cities are too small for that. Only on the outskirts of the cities are buses used that run on diesel fuel.

It's the private traffic that causes the problem, not the public one, and here, a good solution is not in sight. You are correct, we will need to electrify more of the private traffic as well, and we cannot do so, because we don't generate enough electricity for this.

Thanks for the excellent presentation.

I agree that a good solution for private traffic is not in sight. However, the tax-system still promotes long commutes through tax deductions, which should be scrapped. In fact, the tax-system should favor short commutes.

Unfortunately, the planned CO2 tax on transport fuels was dropped, and the current majority in the government is not at all interested in reducing mobility (which they think is bad for the economy, especially the part they have invested in: trucking companies, car-sellers). They don't realise that lower spending on mobility frees up resources (hopefully for heat pumps, minergy housing, creating local jobs).

t. You are correct, we will need to electrify more of the private traffic as well, and we cannot do so, because we don't generate enough electricity for this.

I was obviously unclear.

You don't need to make your private traffic electric, you need to make your private traffic public. Move more people out of their cars and into buses, trams and trains. This lets you have the same movement of people for less energy overall. It increases total electricity demand, but in most cases when you look honestyl at things you find a lot of waste of energy, electricity included. Does Switzerland have appliances with standby power? empty offices with the lights on at night? etc. The energy saved by cutting down waste should more than make up for the extra demand due to more electrified mass transit.

Even without eliminating waste, extra electricity will be easier to find than extra oil would be. For example, Switzerland already imports oil, so it's demonstrated that it's happy to import energy. Can it not import more electricity instead?

If you assume that nothing changes, that everyone keeps driving around and heating their homes inefficiently and wasting huge amounts of energy, then yes you have a big problem. But if you are open to the possibility of genuine change, the problem is still significant, but not so horrendous.

No, I didn't misunderstand you. The number of people making use of public transport and the distances covered by these people on the public transport system here in Switzerland are already now the highest in the world. Here at ETH Zurich, 96% of the employees and students arrive to work on public transport. Only 4% use private vehicles.

The problem is that the public transportation system is already now pretty much in saturation due to the high population density. Trains pass on most routes every 2-3 minutes. The existing rail network cannot accommodate more trains. Almost all trains already feature two floors to maximize the number of passengers per compartment. We cannot make the trains longer, because they already now occupy the entire length of the railway stations when they stop. We cannot make them higher because of the many tunnels. Building new train routes is hardly an option in the most densely populated areas around the lake of Zurich for example. There simply is no space left for additional rail lines.

Of course there would be space to build additional rail lines outside the cities, e.g. along the freeways, but that is not very useful. You don't want the trains where no people are. You want them where the population density is highest.

Zurich may be a bit of a special case, and new rail lines might be justified there. Over most of the country, rail and public transportation in general is far from saturated. The fees are a disincentive.
Simple things like dropping the first class on busy routes would allow more people to use rail. Rail cars could also be redesigned to accommodate even more people.

There is a "peak commuting hour" problem in many places but this also plagues private transportation (rail doesn't slow down while cars are stuck in traffic).
It would be more efficient to spread commuters across more hours than to build more transportation infrastructure. This requires reconsidering cultural norms and meddling in private enterprise but there's no reason it can't be done at little cost. Aside from lessening the load on the transportation infrastructure, many would benefit directly from less stressful and possibly shorter commutes.

If across all Switzerland only 4% of trips were by fossil-fuel-burning car, I don't think you'd have an energy problem.

I don't know what proportion of trips are taken by foot/cycle, car, bus, tram and train across all Switzerland. But since oil imports make up such a large chunk of your energy use, that suggests that total car trips taken must be rather more than 4% of all trips nationally. So you can't really extrapolate from ETH Zurich.

You need a national change away from private fossil-fuel-powered vehicles and onto more electricity-powered mass transit. Even if the electricity came from burning oil, you'd still be using less oil than if it were burned in cars instead.

This is an old problem, as I said: wanting to have a lifestyle not change at all while the resources required for that lifestyle decline.

Sorry, you're just going to have to change. We all are.

If across all Switzerland only 4% of trips were by fossil-fuel-burning car, I don't think you'd have an energy problem.

Zurich is a special case. First, the roads are so crowded that for most people it isn't saving them much time traveling to the city in a private car. Second, you don't find street parking for longer than 2h max. If you park in a parking garage instead, it'll cost you a fortune. All parking garages have a progressive price structure, i.e., the first two hours are relatively cheap, and any additional hour is progressively more expensive.

Sorry, you're just going to have to change. We all are.

We shall, we shall ... the planet will see to it.

In an energy-starved world, more people will choose to live closer to work again, which will reduce the amount of commuting done. Currently, there is incentive to do just the opposite. The rents in Zurich are so expensive that many people choose to live relatively far away and accept long commuting times, because it saves them money.

In an energy-starved world, people will lead less hectic lives again, which will reduce the amount of fuel consumed. Currently, time is money, i.e., people value saved time a lot. Consequently, they will often choose fast (gas-guzzling) cars, instead of public transport, because it saves them time.

I must confess that I am one of the 4% traveling to ETH by private vehicle. I am energy-conscious, and therefore I own a Renault Kangoo with a diesel engine that consumes only 4.5 liters per 100 km, but traveling by car indeed saves me a lot of time. I can travel from my home to my workplace in 35 minutes, whereas the commute would take me 85 minutes by public transport. I would first have to walk for 12 minutes fairly steeply down-hill (we live out in the boonies, where housing is relatively cheap), then wait for a local (diesel-powered) bus that takes 18 minutes to the nearest railway station, then wait for a local commute train that takes 21 minutes to reach Zurich central station, then walk again for about 4 minutes to the nearest tram stop, then wait for a tram to take me in another 5 minutes up-hill to ETH. Since I live sufficiently far away, I have the right to acquire a hunting license to a parking lot in one of the parking garages of ETH. It costs me CHF 120 (about $140) per month.

It won't be possible to move the entire private fossil fuel-powered traffic onto the public electrified transportation network ... we'll simply have to travel less.

Oil wasn't really much of an issue during WWII here in Switzerland.

Private homes were heated mostly using central coal heating systems then. The transition from coal to oil took place only around 1960. Within about 10 years time almost all Swiss homes switched from central coal heating to central oil heating.

A law was passed at the beginning of WWII that forbade heating homes to more than 16 degrees Centigrade at any time, and people were told to only heat their living room. Swiss homes use a central heating system to heat water that is then circulated through radiators located in every room. Each radiator is equipped with a tap to turn it off. As coal was also rationed, the people followed these instructions to the letter, because otherwise, their allotted coal wouldn't last them through the month.

Transportation wasn't an issue either. Switzerland had and still has one of the densest public transportation networks in the entire world with trains and trams all electrified. Private cars were rare before the war, and as no gas was available during the war, those few people who owned cars before the war simply stopped using them. A few obstinate car drivers converted their car engines to burning wood instead of gas.

In 1945, at the end of WWII, Switzerland consumed 1 kW of power per capita. This number increased to 2 kW by 1960.

Why doesn't this show up in the main page?
I just realized I'm not seeing every post by checking it. Is there a page where everything is displayed?

It will. I agreed with the editors of TOD World (the "main page") that this article shouldn't hit the front page until Thursday afternoon or Friday morning of this week. The reason is that I am on travel today and tomorrow (teaching a class in Austria), and it is considered "bad manners" here at TOD, not to be available for discussion of one's own articles. TOD Europe generates much less in terms of a discussion than the front page that is read by many more people, and therefore, I didn't mind getting the article published here first.

Your article talks about almost everything BUT population reduction. Reducing your population back to 4 million or less may be necessary to allow those left living there the ability to live a quality life.
It is unfortunate that there is such a big problem with discussing rationally reducing population to keep it within the carrying capacity of any given country.
Things like:
The possibility of having to go back to the old ways of not allowing children born defective to live beyond birth.
Terminating the lives of violent criminals.
Stopping immigration.
Expelling recent immigrants.
Terminating habitual illegal drug users.

None of these types of things are very pleasant to think about or discuss, but I think it would be better to discuss them before the reality of having to do something (or mob rule takes over) than ignoring the issue. Die off is going to be a real and unpleasant result of continuing declines in energy availability. It can be done with pre-planning and rationality or it will happen by irrational mob rule. And the quality of the remaining population after the reduction will be quite different in the two different cases.

At any rate, something MUST be done to stop the increasing of the population numbers to prevent an even worse situation from developing.

The possibility of having to go back to the old ways of not allowing children born defective to live beyond birth.
Terminating the lives of violent criminals.
Stopping immigration.
Expelling recent immigrants.
Terminating habitual illegal drug users.

Odd, I didn't see homosexuals on that list. Was that an oversight?

At any rate, something MUST be done to stop the increasing of the population numbers to prevent an even worse situation from developing.

I'd like it be known that as a gay man, I'm pulling my weight on this issue. I'm even willing to proselytize for my side but, Lordie, those uptight PTA folks sure can get all hell bent out of shape.


Odd, I didn't see homosexuals on that list. Was that an oversight?

Is this a joke? Homosexuals are great for population control: they are capable of doing honest work (unlike violent criminals or drug users) AND they don't procreate! Perfect combination! How the hell can they go to this list???

P.S. And no, I not a gay man myself - it's just logic: for centures homosexuals were "bad" because goal was to produce as many slaves, soldiers and so on as possible - and they don't procreate so no new slaves. But today situation is totally different: we want to reduce population and so naturally this minus becomes a plus.

Partly. It was my gentle way of saying that formulating a list of who should live or die purportedly in the name of population control is a road best not travelled. If it's ok to kill drug users why not the physically and mentally handicapped? The homeless? People of colour?


Agreed. I don't think drawing up a list like that is useful. A broad effort to reduce population through education and birth control seems to work in many areas of the world where it is earnestly tried. Personally, I do not want to be involved in conversations that are about "who do we kill?"

It may be unpleasant for many who read this site, but soon, those decisions will be made by someone or something. Better to ride the slope in a controlled manner than tumble down it uncontrolled. It will be a matter of survival, choose not, and you will not survive. Simple as that.

So, would you like to be part of the solution, or are you content to be part the problem?


I, would gladly be one who would make the choices needed for survival. I choose to live, and help my family survive, no matter the cost. That is what is coming. Sorry you got in the way, but I will fight to the death, not go quietly into the night as so, so many have in history....

If I have the will and the way, and you have the food, you're history.

Unfortunately, too many feel this way (or will when the chips are down)...

Your statement may also be phrased in (at least at the surface) less unpleasant terms: sustainability is not an option. It will happen, whether we like it or not, whether we fight or aid it. If we don't see to it, our planet will.

Unfortunately, I have little confidence that mankind has the willpower to do anything but talk. We will cut down our rain forests -- all of them. We will destroy our animal habitats. Wildlife will mostly disappear. Legislation protecting these habitats may slow the process down, but ultimately, it will happen anyway.

When the third millennium draws to a close, there will be exactly as many humans living on this planet as the planet can feed sustainably, not one more and not one less ... unless we blow ourselves to smithereens in the process.

We'll breed like rabbits, lead miserable lives, and die like flies.

It's the law of nature.

Humans are not willing to admit their nature as products of evolution is the root cause. Evolution selects for reproduction. We reproduce too much as a result.

I agree we will wipe out more and more of the rest of the species. Suggest population growth control and people will call you fascist, racist, evil, etc. Better to wipe out the other species than to restrain ourselves it seems.

As an answer to Hereinhalifax

This sounds like a fascist dictatorship. And such dictators always liked to have high birth rates, so as to have lots of soldiers to go to war, and lots of nurses to patch them up.

Low birthrates are accomplished in peaceful, democratic societies. And sending back immigrants (as a solution for population control) is plain silly: these people (they are people) go back to misery, which typically comes with high birth rates because you can never be sure that your children survive.

Anyway, this is world-wide problem, and it doesn't make sense to reduce the population in rich countries, while leaving the rest of the world in abject poverty, with high birth rates, and rapidly increasing populations (unless it's your secret - not expressed - hope that they succumb to some plague, starvation, war).

I think your comments are spot on. The notion that we can somehow judge who is worthy of life speaks to a very dark corner of the human mind. Personally, I find it repugnant.


Immigration amnesty increased fertility of Mexican immigrants in the US. Whether we allow people into the country does affect their fertility rate.

As for misery: Mexico's per capita income is above the world average.

Transition Towns are those towns/cities/counties/etc that are taking steps to reduce their energy use and prepare for PO. I note that while Switzerland does not have any official Transition Towns, Baden and Worben have people who are "mulling" transition planning.

Anyone in Zürich, Switzerland, interested?

I like the concept, but to get the critical mass going is tough. Many of my collegues are engaged in all kinds of local initiatives related to traffic, energy, pollution, gardening, so all the elements are there. However, these initiatives already take a lot of their and my time.

If you put a marker on the mulling map, other like-minded people in Zurich will contact you. It will be an excellent way to tie together "all the elements" and give a greater sense of vision and direction. Plus, having many more people involved means more "hands on the oars".

The author of this post should read "Prescription for the Planet," by Tom Blees. Integral Fast Reactors promise safe nuclear power unlimited by fuel supplies, with a waste product sharply reduced in volume and toxicity, all at low cost and with no contribution to proliferations. Perhaps Switzerland will soon change its position on nuclear power, just as England, Italy and Sweden recently have.

Great post, thanks,
The balloon diagram is getting a bit out of date(2005), as far as wind energy; both EROEI is now much higher than 20:1, as this was based on wind turbines generating 250-750KW. A figure between 30:1 and 200:1 would be better,for 3MW turbines depending upon using recycled steel or new steel, location etc.
The other point is that wind energy now contributes approx 1QUAD of electricity( equivalent to X3 FF as you pointed out). I am calculating this as 121GW capacity(x0.3 capacity factor) x8760h/year X3.6J/W. Those changes put wind on a low left to upper right trajectory( ie opposite to oil).

Do you have an data about additional hydro potential of Swiss? especially small hydro. My observations were that many rivers have opportunities for run-of-river hydro.

I enjoyed this post too and will distribute it widely, thanks François Cellier! I would have been interested in seeing you further explore the (probably academic) controversial issues of a 2kW- vs a 1tCO2-society. I am also of the opinion that we should minimize and limit energy consumption even if we find/use energy resources and technologies with zero GHG contribution. But that's more a gut feeling or probably a morally based conviction. It seems to me difficult to find convincing arguments for self limiting ones energy consumption beyond 'fairness' or copying nature's pattern.

Regarding the small hydro power (SHP) situation/potential in CH see (the larger part of the info is in German). Hydro power is well developed in CH and little resources remain to be used. Many SHP plants could still be installed / refurbished, though. For instance reducing the pressure in drinking water schemes in the Alps has been an attractive development area in the recent years. Nevertheless the potential is minor and in total will not exceed a few percent of current electricity consumption. rolf_w

I would have been interested in seeing you further explore the (probably academic) controversial issues of a 2kW- vs a 1tCO2-society.

You find that discussion in my earlier TOD report: New Energy Strategy of ETH Zurich.

According to the Swiss Federal Office of Energy (SFOE), "the available technical potentials in Switzerland have been largely exhausted, especially with respect to large-scale facilities with an installed capacity greater than 10 MW." I couldn't find exact numbers this morning, but if I remember correctly, I read somewhere that about 90% of the water that can be used in large-scale hydro-power plants is meanwhile being exploited.

In general, these projects have been accepted well by the public, because the reservoir lakes actually add to the beauty of the nature, rather than distracting from it. Here two pictures of the Zervreila reservoir lake above the village of Vals (built around 1960):

Yet, there are also downsides to these projects, as many of these lakes have drowned villages. For example, the former (small) village of Zervreila is now under water. Two entire (and not so small) villages have been drowned in the construction of the Sihl lake that provides much of the electric power for the City of Zurich.

The locals aren't always happy about this. The mood of the local population is well reflected in a recent Swiss movie (one of the more attractive Swiss movies shot recently - a thriller and ghost story), called Marmorera, with dialogs partly in Swiss-german and partly in Rhaeto-romanic (Surmiran dialect). The movie was released in 2007.

Yet, this is only part of the story. Some of the water turbines are quite old. Advances in turbine technology make it possible to increase the efficiency of many of these hydro-power plants by 20%, and indeed, many of the older turbines have been replaced in the last 20 years, such as in Birsfelden. I couldn't find data that state quantitatively, how much more could be gained by replacing older turbines.

Finally, a small power initiative was recently launched in Switzerland. People could submit projects to the Swiss government, in which they demonstrated how they planned on generating electric power. The best projects would then receive government subsidies.

Many people submitted projects for placing photo-voltaic panels on their roofs, and as they were made to believe that these proposals would be "sure winners," many of them actually started with the construction, before the competition was over.

The disappointment was large when, in the end, only about 5% of the money was given to small solar power, whereas 95% was given to small hydro power plants. Many hydro-electric companies submitted proposals for small river projects that wouldn't be economical yet at the current electricity prices, but became economic with government subsidies ... and these small power plants were still considerably more economical than the proposed photo-voltaic projects, and therefore received most of the funding.

This had been reported about a year ago in the Swiss media, but I couldn't find a link to the story this morning.


I was at a talk some 2 years ago with the manager of the Birsfelden plant, and he said
they were not satisfied with the retrofitting back then, I vaguely remember figures of
only about 5-10% increased total efficiency. Should have been more.

I dont see why he would have shown lower than real figures, but there could
be some politics involved. In any case they should have figures available with a
phone call.

Thanks for a good article.


Thanks for a well written, well reasoned post. And special thanks for calling my attention to the BP Terawatt-hour / 'million-tons-oil-equiv' conversion issue. This turns out to be a key issue for some charts I am working on for the Energy Export Databrowser.

You are absolutely correct that BP Statistical Review reduces hydropower and nuclear power by 2/3 when converting from their 'Terawatt-hours' worksheet to their 'mtoe' worksheet. This should be taken into account when using a common unit to compare energy usage from different sources.

But it is not clear from your post that the "Sankey" chart is based on the BP data. The original presentation describes the data as coming from the Swiss Federal Office for Energy (Bundesamt für Energie).

It would help if you could verify that the Swiss BFE used the BP 'mtoe' data to calculate Terajoules generated from hydropower but not for Terajoules generated from nuclear power where you have not applied the correction.

Without further information about the provenance of the data, I would suspect that the table in Figure 2. is probably more accurate than the 'corrected' one in Figure 3.

I would like to offer another view of total energy consumption over time. The following is a plot type I'll be adding soon to the Energy Export Databrowser:

(Note -- This plot has not yet been corrected for the conversion factor mentioned above. Should I add units of Watts? Joules?)

It will be interesting to see what the fuel mix looks like as Switzerland begins to ramp down total energy consumption.

Thanks again for a very thought-provoking post.

-- Jon

But it is not clear from your post that the "Sankey" chart is based on the BP data. The original presentation describes the data as coming from the Swiss Federal Office for Energy (Bundesamt für Energie).

No, it wasn't. The factor of 3 in hydro-power is not included in the Sankey diagram. It only enters in Fig.3 of my article. However, the generally quoted statistics about per capita energy consumption in Switzerland is based on BP data. Using the SFOE data represented in the Sankey diagram, Switzerland consumes only 4.5 kW per capita rather than 5.5 kW (excluding gray energy). The factor of 3 is included in the Sankey diagram for nuclear power, however, as we import the nuclear fuel rods and convert the nuclear energy to electricity in power plants here in Switzerland.

For this reason, no "correction" factor was used in Fig.3 for nuclear power.

Thanks for the clarification.

Hello everybody, Thank you Francois, for your great post. I'm living near Zurich and following POD since about 2 months and have finally decided to put my first post.

A few thoughts to your article and to the comments:

- You did not mention the possibility to satisfy our energy needs through large solar plants in southern countries, in the Sahara. So I think we should talk with Gaddhafi or Achmadinedschad not to get more oil from them, but to build up a large infrastructure of solar power plants in the south. I now this solution is still far out of reach, probably less technically but more than all there are large political obstacles to overcome.

-The comparison with the situation in WWII is interesting. This could show a way how to deal with TOD. Though it could be more difficult to battle against a inner enemy (TOD not allowing any waste of energy) as compared to a battle against the enemy/accept a limited time of resource constraint in WWII.

You did not mention the possibility to satisfy our energy needs through large solar plants in southern countries, in the Sahara.

I did not, because this is not particularly a Swiss issue. However, you are correct. In fact, we wouldn't even need to import the electricity from the South. Here in Europe, electricity is currently flowing from the North to the South, rather than the other way around. Therefore by building additional power plants in the South, e.g. in Southern Spain, we would need to send less electricity to the South, and could therefore keep more of it for ourselves. This furthermore increases the efficiency, as we would reduce the transport losses.

... and welcome to TOD!

Here in Spain more than 20% of electicity production comes from susteinable energy sources: this is, not count large scale hidro plants. (Including large scale hidro, last month we had some 43% electicity production from renewables, but water for power will be scarce in a couple of months)

The PS-10 thermoelectric has some 11MW (and is a large scale experiment), the PS-20 will have 300MW.

As for wind, as I write this, we are producing 22% of our electricity from the wind (real time graphs in and here:, and current demand is 28GW, and considering that we only get only 30 to 40% nominal power from wind turbines (unless we have low pressure fronts), go figure the installed base..

If this can be possible in Spain, it must be possible elsewhere.. after all, we are relatively poor compared to switzerland!!

Spain has done very well in recent years w.r.t. renewable power. Your concentrated solar power (CSP) plants in the South of Spain (in Almeria and close to Sevilla) are impressive and ambitious. Unfortunately, CSP plants are more profitable economically in countries located in the subtropics, e.g. in Spain, i.e., in countries closer to the equator with lots of sunshine, than in a country such as Switzerland.

Also, Spain has done well in terms of wind power, but then again, wind is not available everywhere. Switzerland has no plains and therefore comparatively little wind in those places where most people live. We get a lot of wind only on the mountain peaks, and I am sure that it would be technically possible to install windmills there, but we haven't done so yet, because as of now, we are still a net electricity exporter, and installing windmills in those locations is not yet economically profitable at current energy prices.

You mention Cuba's longer growing season and the grey energy of imported food, but the huge problem I see with any northern climate is home heating. The slice of oil and gas going into residential is almost as big as transportation. Any idea how big a slice imported food would be compared to residential or transportation?

I have never seen evidence for the unpopularity of nuclear energy in Switzerland.

In May 2003, the Swiss electorate rejected two popular initiatives on nuclear power ("Moratorium Plus" which aimed at the extension of the ban on the construction of new nuclear power plants for another ten years until 2010, and "Strom ohne Atom" which demanded the gradual closure of all existing Swiss nuclear power plants after a 30 year life-span, and the stop of any reprocessing of spent fuel).

This would indicate just the opposite and the Swiss are fine with nuclear, like their nieghbors in France (and now Italy and Sweden).


Home heating is indeed a problem, and burning the precious remaining oil at low temperature in home heating systems should actually be considered a crime (!)

All new homes should be built to at least minergy standard, if not even minergy-P or minergy-P-eco. Minergy houses consume 40% of the heating energy of regular houses; minergy-P houses consume 20%; and minergy-P-eco houses consume nothing. The latter is only possible by producing energy locally, e.g. by installing photo-voltaic panels on the roof.

The problem are the many old houses here in Switzerland that are under monument protection. Improving their energy efficiency is a daunting challenge and an expensive proposition.

The gray energy going into food production is not very big. You see from the Sankey diagram that Switzerland spends only 1.6% of its overall energy consumption in the agricultural sector. As we import about half of our food, the percentage of gray energy going into food production should be of the same magnitude.

This number is a bit conservative though, because the 1.6% listed in the Sankey diagram are only direct energy used by the agricultural sector (mostly for diesel fuel). However, there is also gray energy associated with the agricultural sector, e.g. for importing farming machinery. If we assume that the gray energy consumed by the agricultural sector is roughly the same as for everything else, we ought to add another 30% on top of the 1.6%, which now gets us to 2.1%.

In addition, I haven't taken into account the energy going into packing, transportation, and refrigeration of imported food items until these items arrive at the Swiss border. Factoring these sources of gray energy into the bill as well, we might end up with about 2.5% altogether.

The economy is driven by several feedback loops. The black feedback loop at the bottom denotes the EROEI. Energy needs to be invested to produce more energy. By 1949, the EROEI is high, and therefore, the feedback is drawn as a relatively narrow vector.

The production of energy also costs money. This is shown by the dark blue feedback loop at the top. Money is also spent for maintaining the infrastructure, as shown in clear blue. Some money is furthermore invested in improving the infrastructure. This is shown in red as discretionary investment.

I enjoyed this post, but have to correct something in it. The black arrow on the bottom is the energy used to "power" the economy, not a representation of EROI. The increasing size of the arrow represents the increasing energy needed to power a growing economy. 1949 through 2005 values are from actual data (I've seen the code), and from 2006 on, the values are extrapolated.

The blue line (which grows much larger over time) demonstrates the increasing investment in energy acquisition, i.e. Energy Return on Energy Invested.

It's my only complaint about the "cheese slicer" diagram - it predicts energy growth through 2050.

The EROEI calculates the energy spent on producing energy, not the money spent on producing energy. The dark blue feedback loop relates to money, and therefore not to the EROEI.

However, I agree that the black feedback loop is more than only the EROEI. It also includes energy spent on infrastructure and, in general, the energy spent on running the economy. This includes the energy spent on producing energy, i.e., the EROEI, but is not limited to it.

I won't belabor the point, but I think that you should read the paper published in David Pimentel's book which explains the "cheese slicer". Especially p. 123-124 (17-18 in the pdf).

Link to .pdf here

I know for certain that the data used to demonstrate the width of the black arrow is based on total quads of energy used in the US per year.

Here's what the authors have to say about the top most arrow:

The width of this line represents the investment of energy into getting more energy.

Again, I enjoyed your paper, but want to make sure that readers are informed correctly about what the "cheese slicer" diagram is meant to convey.

You are correct ... Charlie must have had a bad day, when he wrote the above paragraph ( :-) ).

The wrong questions are being asked.

The writer, understandably of course, assumes business as usual and presents an analysis of how this can be continued. The analysis is useful for a transitional social system--sort of one-quarter of the way between where we are now and where we will need to be.

The entire social system needs to be questioned. We need to re-examine how we live, where we live, and advantages of different forms of inhabiting the earth.

The writer wants to continue with surface-based habitations; to maintain these, we of course need minergy systems. But what if instead of surface habitations we talked about sub-surface habitations? In this case, we would not need heating or cooling systems. If, in addition, we had sub-surface habitations, we could also have sub-surface gardens that could grow food year round.

Then, again, we need to question the BAU assumptions of the 2000 Watt society. Could we eliminate the need for electricity entirely? Or, could we develop ways of generating electricity or using it that had minimal impact, like geothermal? Could we harness natural electricity, as they did in the early years of telegraphy?

Why do we assume that we must have what we have now, only make do with less energy? Why not work with different assumptions? Maybe 100 Watts would be enough, maybe zero Watts would be better. We need to import oil for heat only because we have surface habitations; different habitations would require no heat, hence no oil or gas for heat.

we could also have sub-surface gardens that could grow food year round.

This is interesting, can you provide examples?

Toadstools, fungi, I suppose. Certainly, not a very substantial diet.

Antoinetta III

I'm sure I remember the 'Diet of Worms' when I was awake in history class..

Some undergound homes are very comfortable
They are supposed to be 26C inside when the outside temperature is 50C. Mind you they have little danger of flooding. Reflective light tubes to the surface combine lighting and ventilation.

In practice the occupants just grow a few tomatoes with dishwater in a shady garden on the surface. Water has to be bought by the tankload for $5 a kL produced by reverse osmosis of saline groundwater. I'd guess a cavern suited to mushroom growing would need permanent damp air flow, not suited to human habitation.

Excellent post.

Pmax = - a / b

Thanks. I had planned to place a minus sign in the differential equation itself, but then forgot to do so. I'll fix it right away.

Once again, top post.

Because I hadn't seen it before (my ignorance, perhaps), I was interested in your argument that the law of large numbers dictates a gaussian shape in regionally or globally aggregated oil production v time statistics ... but I think it's wrong. First, I guess you actually meant the central limit theorem. The law of large numbers refers to the tendency of the sample mean to regress to the population mean as the sample size increases. The central limit theorem says that if you sum (actually average) enough probability distributions (regardless of their shape), the result will be a normal distribution (i.e. a gaussian).

As far as the math goes there's nothing magic about probability here. Probability in some parameter space could just as easily be oil production over time, so the basis is OK. But there are caveats. Probability distributions have the special characteristic that their integral over the parameter space is always exactly 1.0. That is, they're all the same total size. That's not the case for oilfields at all. They vary enormously in size. More importantly, in the CLT, the summed distributions must be independent. But oil field outputs are not like that. They cluster together in time. And one field's production affects the next via price and cartel mechanisms. Sorry, nice idea, but the CLT doesn't apply.

That said, there's no doubt at all that aggregated production statistics tend to follow a bell curve. But I think the reason lies in physics and economics, not statistics. The ultimate recoverable oil from a given set of oil fields using a given set of recovery technologies really does have a finite limit. Just as the simple logistic function does (Pmax!). And the nature of those recovery technologies and the economics of their application tends to make the aggregate production approach that limit asymptotically, in the manner described by the logistic function. The derivative of which is a (gaussian-like) bell curve, as you say.


Once again, you are correct. I meant the central limit theorem, and indeed, it doesn't apply in a strict mathematical (statistical) sense for the reasons that you mentioned. Also, Hubbert himself never used that argument. He talked about a "Verhulst" distribution, i.e., he went directly with the logistic model, rather than postulating a Gaussian first and then claiming that the logistic model approximates that said Gaussian.

The logistic model is widely used in ecology. When you model a single-species ecosystem, the population grows exponentially at the beginning, but the exponential growth comes to an end, as the species exhausts its resources. The logistic equation is the simplest mathematical model that reproduces this behavior, and in many ecological experiments, the logistic model approximates the observed behavior fairly well.

The same argument that is used in ecology applies also to oil exploration. Oil exploration, in a free market environment, has to grow exponentially at the beginning. The exponential growth will eventually come to an end, as the oil gets exhausted, and once again, the logistic equation is the simplest mathematical model reproducing this behavior.

Yet, we cannot be sure that the logistic model offers a perfect approximation. Even the fact that the oil exploration statistics for the U.S. followed the Hubbert curve pretty well is not an argument that the same will hold true for world oil exploration. The reason is that, when U.S. oil peaked, the prices remained the same as another source of oil was available to compensate for the local shortfall.

In world oil exploration, this is not the case. As we cross the peak, oil will become more expensive, and consequently, some deposits that we already know about but couldn't exploit before economically due to the low oil price suddenly become exploitable. Some of the conventional oil may be replaced by non-conventional oil if the price of the commodity rises enough. This may keep us on the plateau for a little while longer.

However, I don't think it will make all that much of a difference. As the oil price rises, demand destruction sets in, as we already experienced last fall, which limits the gradient in the rise of the oil price. Initially, conventional oil will still have an EROEI that is larger than that of non-conventional oil, and consequently, the conventional oil will be produced first, until its EROEI has shrunk to a value comparable with that of other types of oil.

Thus, I would be very surprised if the assumption of a bell-shaped oil exploration statistics resembling a Gaussian wouldn't hold.

I live in Geneva.

Thanks for pulling all this together in one post, Francois, will send it around.

Around me, ppl are very aware of peak oil (microcosm maybe, but contrary to OPs take), and support, so to speak, alternative energy and even saving energy, though without stronger Gvmt. incitation and/or support there is not much hope.

As OP and others may know, investment in Geneva transport away from the car is absolutely massive, tram lines everywhere and soon no space for cars left.

I took a cab the other day and the cabbie, aged about 40, waxed lyrical about dying breeds. His son would become an accountant and marry a pop singer!

Sometimes, one can feel a party-end-of-the-world atmosphere, use it while you got it kind of thing...though I guess this also has much to do with bankers spending their last salaries or bonuses...Anyway, people are very ‘au fait’ on peak or diminishing energy, can even quote numbers. The plumber who did some minor work today in my bath room had very interesting things to say about energy, water, plumbing, and heating, and mentioned ASPO.

(... Anecdotes!)

Not so for food or agriculture. Ppl are not aware of food imports in CH or of the food industry as a whole. They seem to see Switz. as a morally just (organic, ‘bio’ agri, etc., traceability of food, supermarket practices that are superior to our neighbor, France, recycling of biological detritus, and of everything else, not practised in the same way in France or Italy, my plumber brought this up right away..) - the image of a kind of mini pastoral heaven, where cows are treated right in folkloric tradition, pesticides are not used ‘too much’, local veggies are abundant and nutritious, cheese is made to traditional *and* sanitary specifications, etc. holds sway.

No clue, ppl don’t know what they eat, they don’t relate it to the energy cycle. They buy new light bulbs, turn off appliances, but the supermarket provides what essentially is a free lunch.

As for Minergy standards, on the ground they don’t work well. I just renovated a decrepit falling down house and despite the best intentions I got no subisdies (I’m not complaining about not being paid) - the problem was, and is, as it is ongoing, competition between different Gvmt. agencies.

As an example, I have two ‘french’ windows with single pane glass from 1950(?), and am not allowed to change them, despite hiring a reputable, influential, architect at for now unknown cost. I also could not obtain permission for any solar panels, I didn’t expect to do so, and might not have installed even with permission - the point is that nobody, including the architect, would even consider embarking on such an adventure.

Another bone of contention has been the shutters - I wanted new and tighter; not allowed. So it makes a mockery, really, of any individual trying to do their best. I can’t afford lawyers and courts, so here we sit..with me making invisible interior insulation... /end rant/ But such stories are very common here. Scandalous.

Minergy works well for new building. It doesn't work well for renovating old buildings.

That's right. Still, I expected a little better. Or some common sense. I was unpleasantly surprised, had no experience at all, and believed in the positions espoused in public.

Hello Francois

Congratulations for your courage to come up with an energy crisis warning on the occasion of the physics colloquium. I regret very much that I learned about it only in hindsight, as a TOD contribution. For sure you will be criticized for bypassing the ESC, for expounding very simple (yet unwelcome) physical facts at the physics colloquium, etc etc.

Living in the town of Zurich, and currently engaged in a project for energetic improvement of my old house, I’m not really happy with your remark about minergy not making sense for old buildings. I notice you didn’t give any reason for that observation which may in fact discourage people. You can find many examples in our country where homeowners have managed to bring their poorly insulated old house up to minergy standard.

But it is not even necessary to go for such a far-fetched goal. There are always simpler possibilities to improve the energy consumption for home heating quite a lot. Given the enormous number of existing buildings (most of them of course not protected as historical monuments), this would be really important, No question that it’s easier for new buildings, but why not insulate the old ones, replace the windows by modern ones with virtually no energy losses etc.

Like Noizette at Geneva, I made the funny experience that I’m not allowed to improve the insulation of my house unless the new condition does meet a very high level of insulation – I just will not get permission by the authorities. In other words, I may happily live with the lousy old quality and go on wasting energy rather than execute a significant improvement, if the improvement doesn’t meet the new very high standard. That’s probably not a very intelligent condition.

Once again, ‘Chapeau’ for your very instructive lecture

I am sorry, if my remarks were misunderstood in this fashion. I didn't mean to say that improving the energy efficiency of older buildings doesn't make sense; only that going all the way to minergy standard would in most cases not be realistic.

I myself live in an old farmhouse built in 1857. Our house is made from stone with walls that are more than 1m thick. Yet, the house is not built from bricks. The stones were simply placed on top of each other with very little cement holding them together. Hence the insulation value is rather poor. The house has still its original wooden doors that don't fit tightly.

We cannot seal the walls from the outside, because if we do, humidity will build up inside the walls. This humidity would eventually destroy the house. We did seal from the inside as well as we could, but we don't come even close to the insulation that a modern house offers.

We didn't want to replace the doors, but we placed rubber fittings between the doors and the door frames ... with mixed success.

We replaced all of the single-pane windows by triple-pane windows, which helps.

We also re-roofed the house. The roof had originally not been sealed at all.

We threw out the central oil heating system and replaced it by a heat pump with geothermal and solar support.

Hence we feel that we have done pretty much everything that we could in terms of improving the energy efficiency of the house, and yet, we have not come even close to the energy efficiency of a modern regular hose, let alone a minergy house.

Furthermore when you renovate an old house, you need to take into consideration the energy that goes into constructing the material that you use in your renovation.

If you build a single-family house from scratch, you spend on average as much energy in the construction of the dwelling as you'll use to live in it for 50 years. Thus when you renovate an old house, you have to consider the "amortization period," not only in terms of investment, but also in terms of energy.

A very interesting and informative article but this paragraph highlights an assumption that a future energy source will be available to decommission these plants as well as take up the slack they leave.

Hopefully by the time the new nuclear power stations need to be shut down, we shall have come up with other sources of energy to pick up the remaining load. If we are lucky, we'll have these new sources of energy on-line even earlier, and in that case, we may be able to retire our nuclear power stations even before their licenses expire.

I think peak uranium is a real concern as pointed out elsewhere on this site. Sorry to sound negative but I don't believe that nuclear is an efficient or safe electricity generator.

Nuclear power is both fairly efficient and fairly safe, but it is not sustainable. Replacing the current generation of nuclear facilities by another generation will simply buy us some more time. Hopefully, the reduction in available fossil fuels will hurt us enough to keep us on our toes. The prolonged nuclear power may then be used to hopefully keep the grid up sufficiently long to enable us to come up with a sustainable replacement before we run out of energy once again. The goal is simply to spread out the transition from exponential growth to sustainability. What hurts us most are rapid changes. Those are catastrophic.

Sorry, not on this subject, but just looking at Saudi's production, consumption and export from this months oil monthly from Rembrandt.

Available export from Opec was going down through the high oil prices (chart 51). But oddly enough, Saudi's internal demand soared about 700,000 b/day (chart 23) through this period and at the same time the reported production numbers also went up by about 700,000b/day (chart 62). The net effect was none of this supposed production would have been available for export. Or maybe the oil was just never really produced and consumed. The numbers just made up? Which would put the peak date back to 2005.

Has anyone else noticed this or have a logical explanation for this or for such a spike in internal demand in Saudi at this time? Cheers.

Hi Francois,

Switzerland cannot feed a population of close to 8 million people from food produced locally. Switzerland is in fact the worst of all European nations in this respect. We rely heavily on food imports beside from energy imports.

Have you heard of a chap called Sepp Holzer? He has been experimenting with growing crops in Alpine conditions. I know its based in Austria - but I would think something similar should be possible in Switzerland. Also while not a panacea, it does point to the real hard lateral thinking that is needed to change the whole culture of a society. But then as Sepp says:

"I find it painful to watch all these farmers going broke and selling their land for next to nothing, mostly to rich academic people who know even less what to do with the land. If these farmers only knew what they could do with their land! Nature has so much to offer, so many possibilities!"


I have seen a documentary about him on TV a while ago. The problem with growing crops under Alpine conditions is not only related to higher altitudes (accompanied by a shorter vegetation period), but also steeper slopes. A lot of the work that one can do in the lowlands with farming machinery has to be done manually at higher altitudes ... which is exactly what Holzer advocates: small fields, lots of different crops rather than uni-culture, manual labor.

For the time being, food is too cheap to grow crops under Alpine conditions economically. Right now, the best way to use the Alpine lands is as grassland for cattle during the summer months.

Yet, we have already operated under different economic models during WW-II. We can feed more people on local crops than we currently do (less animals, more greenhouses, etc.), but there is no way in the world that we can feed 8 million people from local crops alone.

The problem with growing crops under Alpine conditions is not only related to higher altitudes (accompanied by a shorter vegetation period), but also steeper slopes.

As is pointed out in this video one session with a mechanical digger creates something that will last for generations. In this case a set of terraces.

A lot of the work that one can do in the lowlands with farming machinery has to be done manually at higher altitudes ... which is exactly what Holzer advocates: small fields, lots of different crops rather than uni-culture, manual labor.

When living on 2kw, there might be a lot of manual labour lying around.

For the time being, food is too cheap to grow crops under Alpine conditions economically. Right now, the best way to use the Alpine lands is as grassland for cattle during the summer months.

As I said its not a panacea, but as I also alluded to, the need for lateral thinking outside the box of BAU (business as usual) is needed NOW while we still have the cushion of abundant energy.

Yet, we have already operated under different economic models during WW-II. We can feed more people on local crops than we currently do (less animals, more greenhouses, etc.), but there is no way in the world that we can feed 8 million people from local crops alone.

Again its not a panacea, but if it can help reducing imports, along with a planned population decline through humane birth control, it is at least addressing some of the problems of long term sustainability as opposed to the BAU approach of sustaining an altogether unsustainable culture.

Food for thought if nothing else...


If we are lucky the bumpy production plateau before peak oil last long enough that people will take up before the sharp oil production decline sets in. We have many ways to adjust to oil production decline. We just need people to wake up and accept the necessity.

Switzerland needs more nukes, not the same number. Switzerland also needs to make a big shift from oil and natural gas heating to ground sink heat pumps. Substituting electricity for other forms of energy is key to adjust to a post-peak environment.

Liquid-to-liquid heat pumps with geothermal support on the primary side and solar thermal support on the secondary side are often a good solution even for older houses, as they provide plenty of heat while minimizing the need for electricity.

Yet, our authorities will not grant a permit for a geothermal system if there is ground water underneath the house (due to the risk of contamination, if the glycol of the geothermal system should ever leak into the groundwater). Unfortunately (or rather fortunately), ground water is present in lots of locations here in Switzerland.

Also, they will not grant a permit for a geothermal system in the inner cities, because there must be at least 4m between neighboring holes, i.e., your own geothermal wells need to be 2m away from your property line on all sides, and that usually isn't possible in the inner cities.

Furthermore, the authorities will often not grant permits for solar thermal systems in the inner cities out of concern that these will change the character of the cite. Houses in Switzerland rarely have flat roofs due to the snow load in the winter, i.e., solar collectors mounted on roofs are therefore usually visible from below.

Many of our houses in the inner cities are many centuries old and are under monument protection. With those houses, you cannot modify anything that would change their outside look. As one of the Swiss readers commented, you cannot even replace single-pane windows by double- or triple-pane windows, because the metal siding between the layers of glass would be visible.

Sometimes, our authorities carry the idea of monument protection just a tad too far.

The presence of ground water is no problem for ground source heat pumps in Sweden. If you got moving ground water its seen as a good thing since that brings fresh heat energy. It is also ok to collect heat with a collection loop in a lake. But glycol is usually not used as anti-freeze, 25-30 % ethanol is the norm and you need to have at least 30 m to any well that might be used for drinking water. The largest environmental problem from a leakage is the laws requiering substances that makes the fluid undrinkable.

The number of ground source wells drilled in Sweden is now about 300 000 and still increasing, our population is 9 million.

That's pretty good. Here in Switzerland, we have currently geothermal systems installed in approximately 40.000 private homes, often with two or three holes each. Our current population is close to 8 million people.

Most companies here drill to a depth of 90m. That suffices to heat 100m2 of living space in a modern house here in Switzerland (8kW of heating power). Thus, most modern single-family homes require two holes.

For our farmhouse (170m2 of living area), we needed 3 holes, as it is an old and energy-inefficient house.

In the US I've never heard of the use of glycol in ground sink heat pump systems. All the systems I hear about either use ground water or they use closed loop water.

Opposition to solar due to character of housing: We have the same problem in Santa Barbara California even though the locals here fancy themselves to be committed environmentalists. I know people who are trying to get solar photovoltaics approved for their house. But those solar panels make the house look less traditional. Can't have that.

My take on these kinds of opposition to needed changes: They are making the eventual changes that much more painful when it finally becomes a crisis. The changes will need to be done while economies are shrinking and the price of energy and building materials are rising.

The opposition to these changes comes in the US from the same political left that cries the loudest about the need to stop global warming. What impractical people.

In Santa Barbara, it never freezes. Thus, water will work fine both in solar collectors and in geothermal systems.

When my wife and I still lived in the U.S., we had solar thermal on our roof in Tucson, and there, we simply circulated water from the water heater through the solar collector. In contrast, in our weekend house in the White Mountains of New Mexico, we had to circulate glycol through the collector on the roof and use a heat exchanger at the water heater, because the temperature often dropped below freezing at 6400 ft above sea-level.

We didn't have geothermal systems at either location, but I am pretty sure, the same distinction would have applied to geothermal systems at the two locations.