The First Wave Energy Farm of the World...It's About Time...

On Tuesday the 23th of September, the deployment of the first commercial wave energy farm in the world started. A Pelamis unit was towed into the sea, connected to an underwater cable and moored to the sea floor, at a site were it will stay for the next 15 years. The Industry was present at the highest level, as so a Minister and even the Navy showed up with a frigate to join the celebration.

But is it all roses? Below the fold are a few thoughts and calculations that show how this is truly a green energy source. Green as in immature, that is.

The basics on Pelamis and the Aguçadoura I Project can be found here.


Two and a half years behind schedule, after legal and technical delays and the sale of the main commercial company (Enersis) to Babcock & Brown, the first pelamis was finally permanently deployed. A high profile event was staged to signal the day, with the Minister of Economy (Manuel Pinho) and an entourage of CEOs and journalists embarking on the Portuguese Navy frigate Corte Real to follow the tug boat trailing the red serpent to its final resting place, 5 Km off the coast, by the village of Aguçadoura.

The pelamis units spent much of the last two years in the port of Peniche waiting for this day. After legal clearance the company struggled with technical difficulties, especially concerning the undersea cable that connects the mini-farm to the shore. The Pelamis engineers developed a floating plug that allows the connection to the cable without the help of divers. But unfortunately the system had been tested in shallow waters and failed in the deployment site, where a deeper water column exerted different hydrostatic pressure on the plug. Solving this issue alone took more than a year.

After a few rehearsals at sea and some tuning of the units for better adaptation to the site, the green light was given. The first serpent is in place with the next two being deployed these days, depending on the weather.

Manuel Pinho compared the event to the dawn of Wind Energy, that fifteen years turned is a story of success. He hoped that the same can be said about Wave Energy fifteen years from now:

The future of wave energy starts today.

Finland is very good in mobile phones, Portugal wants to be good in renewable energy. We are among the top five in the world, and we are just in the beginning of the process.

Renewable energy is the source of energy for the future and we think this can create an industrial revolution and a lot of opportunities for jobs and research and we want to be ahead of the curve.

The read serpent being put in place. Picture by João Abreu Miranda/EPA.

The Cluster

A new agreement was signed at the occasion with Pelamis Wave Power (the technological partner) having a 23% stake, Babcock & Brown 46.2%, EDP 15.4% and Efaced 15.4%. This new consortium will proceed with the Aguçadoura II project, that will be a larger scale farm, constituted by 25 pelamis units, summing up 18.75 MW of installed capacity. The press is quoting the project as costing up to 70 million €.

But these companies have longer term horizons; Leocádio Costa, Enersis' CEO:

What's programmed in the second phase is for 40% of the project being built nationally by Efacec, which is our largest producer of transformers, and with which makes all the sense he had talked to for the set up of a Cluster.

The Government providing us the licences, we are ready to go up to 500 MW in three or four different zones [along the Portuguese coast].

Alberto Barbosa, Efacec's CEO:

Through the years we will grow in Portugal and increase installed capacity, but afterwards we can proceed with that technological development at world level.

Portugal can be the Denmark of wave energy. The question is the political will to concede that installed capacity.

This Cluster in the prospects of these companies is an inception environment that would propitiate wave energy technology development, promote local component manufacturing and assembly, eventually creating an exporting industry. Talks are under way with steel transforming companies to join the project and new experiments with alternative wave technologies are being planned.

Pelamis Wave Energy will deploy the first water snakes (four in total) in their Scottish home shores next year off Orkney. Following that, seven are planned for deployment off the northern Cornwall in 2010. Other sites are being considered in Spain, France, Norway, North America and even South Africa.

Click to watch a movie summarizing the concepts behind Pelamis.

The Algebra

Now, let's go back to the black board and do a little algebra. Last time I showed some concerns towards this project given the money involved for such a small installed capacity (the three pelamis together don't sum up to a state of the art wind turbine). With the delays the project's costs are now reaching 9 million €.

Using a base load factor of 30%, the three pelamis of the Aguçadoura I project will generate in a year about 5.9 GWh (2.25 MW * 8760 h * 0.3). In my monthly electricity bill the kWh is rated at 0.12 € (that accounts also for grid maintenance and management, but let's take it at face value as an upper end estimate). Hence the yearly revenue of the project will be just under 700 thousand €. Or putting it another way, it will take 13 years for the break even, at best.

Each pelamis unit has an expected lifetime of 15 years. Considering that those 9 million € are not counting with maintenance costs, it is not a stretch to conclude that the financial return on investment (ROI) is close to 1:1. Where that leaves EROEI is not easy to envision, but it might not be that far off.

This could be a scalability problem, being the Aguçadoura I just a mini-farm, taking much of the burden of first time tuning to the site. But the press already has the figures for Aguçadoura II, 25 serpents (down from the announced 34 in 2006) and a 70 million € budget. This project will generated circa 49 GWh (18.75 MW * 8760 h * 0.3) of electricity per year resulting in a revenue of 5.8 million €. Break even arrives at 12 years of operation, again with best estimates for electricity prices and without maintenance costs.

The problem (as I stated in 2006) is that while a MW of installed Wind capacity costs about 0,4 million €, Pelamis is costing in the order of 4 million € per installed MW. There is a steep development curve ahead before competitiveness, more over taking in account that offshore Wind energy has a higher load factor (40%) and operates essentially during the same periods (waves are higher when the wind blows stronger).

Even if Pelamis manages to deal with low EROEI, this technology will likely stay in small market niches were Wind power doesn't reach, either be it due to visual impact, water depths or implantation difficulties. Looking long term this type of systems may be used to complement already in place Wind-farms using the space between windmills and taking advantage of the already existent electric connection to shore.

Is the future of the red serpent as clear as the sky? Picture by Catarina Pereira.

An Energy Policy Dilemma

With such prospects, why are these companies so eager to expand the project? The answer is simple, the state pays a feed-in-tarif of 0.23 € per kWh generated by renewable energy producers. This appears to be a good policy, guaranteeing a price for the electricity generated in the country, speeding up the phase out of fossil fuels, that are imported in their entirety. In that way a favourable environment is created for new energy sources to grow and develop.

But there's a huge downside to it: this subsidy is masking the low EROEI of some of these new energy sources, that otherwise should be preventing ill fated projects from surviving in the market. As seen from the Pelamis example, while the Aguçadoura I is an interesting development project from which architects and engineers will learn and improve, the Aguçadoura II does not represent any visibly evolution in technology, presenting essentially the same EROEI. Still it will be a profitable business for the companies involved, at the cost of the Executive Budget, representing a tangible money transfer from tax payers to private business, some even held by foreign capital.

This dilemma faced today by the Portuguese government will be one of the most important issues energy policy makers worldwide will have to deal in the transition away from fossil fuels: how to draw a line between those new energy sources that are really helpful for society and those that are not. Correctly measuring EROEI and determining how it evolves along the development phase of new technologies will have a crucial role in the Energy Policy of the XXI century.

I hope that this Cluster idea really turn out to be a success, and that development allows for Wave energy to became a useful part in our future energy mix. And not only for the sake of the country's industry but also for the negative social effects that the failure of the policies supporting it may bring.

The elements gathered here are based on the following news services:

RTP (Portuguese)
Jornal de Notícias (Portuguese)
Público (Portuguese)

Previously at TheOilDrum:

Tapping The Source: The Power Of The Oceans
Pelamis: A Shot in the Dark?

Luís de Sousa
TheOilDrum : Europe

It is interesting to note that Scotland, home of the Pelamis, seems to be going for tidal energy in a big way having an excellent tidal resource.

I suspect that running the figures for tidal would produce a much more favorable result.

The target in Scotland is 3GW of installed wave and tidal capacity by 2020. That's about 50% - 60% of Scotland's electricity requirement.

Listen to Professor Ian Bryden (University of Edinburgh) talk about this at (6 minutes in)


Scotland is to marine and wind renewable energy what Saudi Arabia is (was?) to oil. Apparently.

Location, location, location.

There are a handful of places, mainly Britain, Hawaii and Australia, where there's a lot of wave power. Like Iceland's geothermal, it's a specialized niche. So it will be hard to get enough capital to bring down costs. But Britain really needs the juice right now so they should have pushed this a lot harder a lot earlier. Same for Hawaii. I guess Australia will always find an excuse to burn more coal no matter who's in the government.

I'm for more tethered flying wind power research because it's more broadly applicable. It's not like there are going to be a lot of private planes operating in the future.

Sounds like "we are losing a dollar on each one, but we'll make it up on volume" type of deal.

I wonder what justification did they present to get those taxpayers money? It doesn't make sense to subsidize an energy source if it's not shown that costs will drop to a competitive level in the long run. In this case wave should compete with the next better renewable energy source - wind, and from these numbers I don't see any advantage, not even potential one.

I see at least three areas of potential advantage which these numbers cannot offer any answers, yet.

Electricity Price
Equipment Durability/Replacability
Sea Conditions

1. Is it reasonable to assume that a price of .12 euro/kwh would stand for the next 15 years? I don't expect the cost of electricity in the US to be so kind. So ROI could improve considerably. (Could worsen, too, I suppose)

2. Constantly Moving parts + Salt Water + Storms. and YET, Modern Materials, Replaceable Seals/Joints, Many industries that are experienced with building for the Seas, etc.. Who knows whether that 15 year estimate is going to prove too short or too long. I won't be placing any bets.. except that this number is going to change. But even at the end-of-life, will there be major elements, like the float-pontoons that can be re-applied to the next generation, cutting the replacement costs signifigantly? How long do tanker/freighter-hulls last?

3. The output of a Pelamis-farm is, of course one of Prime Locations .. rougher seas and proximity to the end-users/grid connections will affect the earnings and payback, while the ruggedness of the equipment will probably reveal just how extreme a condition these systems will operate profitably in (if profitable at all)

A lot of potential.. and a lot of risk.


1.If the price of electricity goes up (which certainly will) the cost side of these projects will go up too.

2.Two years ago some readers pointed that 15 years is an optimistic estimate for semi-submerged steel structures. As for other materials let's hope they kick in soon.

3. Let's hope things go better in Scotland and Cornwall, but we get pretty rough seas during winter. And take in account that above a certain wave amplitude pelamis shuts in.

If the price of electricity goes up (which certainly will) the cost side of these projects will go up too.

But of course, the energy rates are going up AFTER you've built the installation, and while it's gleaning the benefits of higher prices. You're not buying and fabricating that steel over the lifetime of the device, only at the beginning, when prices are ostensibly their best. This mirrors the argument for many of the renewables that take a big investment, but stand to have a considerable upside, particularly if the energy scene worsens, as I think we agree that it must..

Anyway, by and large I agree with your cautious view in this post, save that I don't think the figures really tell us nearly enough to know if this idea really has positive or negative buoyancy.


But if the NEROI is close to 0%, then that's just a system for hoarding energy today for use later when its more expensive.

The argument in its favor sounds like the infant industry argument, but its more along the lines of putting a wide range of bets on technological development, given that if only some of them pay off, they will pay off well enough to cover the whole range of bets.

In that strategy, there does need to be a way of sunsetting the losers ... perhaps allow a technology specific feed-in tariff for a decade, after which time it lapses to the baseline feed-in tariff that any renewable, sustainable energy source qualifies for.

My issue with wave power of this kind is pretty fundamental - to be useful, a wave power device has to move with quite small waves, yet it also survive waves with perhaps 100 times the energy.

Building an oil rig which simply has to disregard all waves is a much easier challenge.

I'd expect that one of the pivotal (?!) decisions to be made is what wavelength(s) to scale your equipment for.

As I toy with images for wavepower extraction, I think of something like the Pelamis, perhaps, but have an array of 'millipede legs' extending off the sides as well, with floats at the ends.. these would be activated by smaller waves and incidental movements of the system.

For surviving heavier weather, I wonder if it's flexibility isn't actually a benefit instead of a problem.. as long as it has enough resilience and range so that it doesn't end up hitting 'hard stops' at full extension of a joint, which would eventually tear apart. The wear on the mooring and related tie lines might also have potential for using those forces to both create more energy and to introduce more malleability into the overall system..

Or to look at it somewhat esoterically..


A man is born gentle and weak.
At his death he is hard and stiff.
Green plants are tender and filled with sap.
At their death they are withered and dry.

Therefore the stiff and unbending is the disciple of death.
The gentle and yielding is the disciple of life.

Thus an army without flexibility never wins a battle.
A tree that is unbending is easily broken.

The hard and strong will fall.
The soft and weak will overcome.

Lao Tse - Tao te Ching

I'd think a millipede would have too many moving parts. But it looks like there's quite a bit of room to move up the number-of-joints/pontoon-length ratio for Pelamis.

More joints and shorter pontoons for shorter wavelengths. I wonder if the design we see here isn't just three joints for a quick feasibility demonstration?


I would agree that wave power will at best be a niche application only suitable to those locations having typically large and steady waves. In the northern hemisphere these are mainly confined to the those coasts facing a long 'fetch' of ocean, such as Norway, Scotland, some parts of the western coasts of England and Ireland, and Portugal. In the US it would be mainly the New England coast and parts of the coastal areas of the Pacific Northwest.

Regarding the economic issues, I think that it might be a little bit unfair to compare the cost of the very first commercial wave power installation with wind power, which can now be considered a mature technology. There is always a great deal of trouble-shooting, redesign, and reworking for a first commercial installation, and all those things cost money. Whether wave power will ever be competitive with wind power remains to be seen, but a legitimate comparison cannot be made using the first wave power installation.

I've studied wave power a bit, mostly from a technical interest standpoint. The nice thing about the Pelamis system is that it is very survivable, a major stumbling block for other types of wave power schemes. When a dangerous storm kicks up, all one has to do is to deactivate the hydraulic rams, and then the four steel 'sausages' no longer resist the relative motion between them and just loosely ride the waves. In other words, the Pelamis system doesn't fight the storm; it goes with it.

The other thing is that a base load factor of 0.30 for wave power strikes me as a bit low. I would think that at a give location the base load factor for wave power should be at least equal to that of wind power, as offshore waves tend to be more steady and less prone to short-term fluctuations, though I am by no means certain on this point.

Anyway, I am anxious to see if Pelamis can make a go of it over the long term, and without massive government subsidies.

Having been born and bread on the west coast of Ireland The Load factor of 30% seems very low . It will depend on the sinificant wave hight the Pelamis need to generate usful power. From experience on the west coast there is only 3-5 days a year where the sea is actualy flat calm. Even after 2-3 days of no wind there will still be a large roll(up to a meter) but no surface chop.

Whilst there might be waves most of the time the energy in them will vary over the course of the year.

As such the capacity factor can be almost anything the designers choose it to be as it is a function of how much energy is captured (and transformed) on average over the year in relation to the rating of the machine.

The capacity factor can be 'improved' by lowering the rating of the machine - this means that you would be throwing away energy you might otherwise have captured (at relatively little cost for some extra rating).

Likewise you can increase the rating and capture a bit more energy from statistically less frequent but bigger waves. However rating costs money, so this only makes sense if the extra energy captured gives an economic return for the additional investment in rating.

Capacity factor is somewhat of a red herring. All that matters is energy captured per unit capital cost (or energy cost if you prefer).

On the Pelamis website it states that the energy payback is currently around 20 months. De Sousa's attempt to equate financial ROI with energy ROI is quite simply just wrong as many commentators here have noted.

His facts on the costs of offshore wind are also completely wrong. It does not cost €0.4/MW but closer to €3.25m/MW.

The statement that the second phase of this project was supposed to be 38 machines is wrong. It was always ~20MW (see Pelamis website).

The statement that there was no R&D is also wrong. PWP developed a new plug as noted at the start of this article which had a problem causing a year's delay, but this is to be expected when doing a first-of-a-kind project.

The design life of offshore wind projects is typically 25 years. Wave energy projects should also be able to achieve similar lifetimes (as indeed do floating and fixed offshore oil and gas platforms). If this can be achieved (and assuming some improvement on using less steel etc in future designs) the EROI could be quite significant.

The cost of installed capacity for offshore wind is around 2,3 €/W.

The cost of installed capacity for onshore wind is now 1.3 €/W. But this is due to recent up tick caused by lack of productive capacity; 0,4 €/W was a valid figure two years ago.

In 2006 the aim was to have a farm with 38 machines, but since then Enersis has been forced to scale back.

PWP developed a new plug as noted at the start of this article which had a problem causing a year's delay

Those costs weren't supported by the commercial company. The project's budget is essentially the same since its inception.

On the Pelamis website it states that the energy payback is currently around 20 months.

Very well, so why is it so costly? 70 million € for 25 units?

The cost of installed capacity for onshore wind is now 1.3 €/W. But this is due to recent up tick caused by lack of productive capacity; 0,4 €/W was a valid figure two years ago.

I simply don't believe this 0.4 €/W figure - please provide references. According to wikipedia, current price is 1.3 €/W and the 2005 price was 1.1 €/W.

Production capacity is blamed for the increase, but please note that metal prices has risen considerably during this time, as well as the price on energy required to build and erect the wind towers.

I believe wind power technology has matured and its production has become large scale, so the price of wind power likely won't go down from here, unfortunately.

(Nuclear on the other hand is half the cost of wind and has the potential for further development, standardization and scaling to decrease costs further. It was really positive that India has been let in from the cold regarding access to civilian nuclear power tech - that will save the global environment a lot of coal-related stress.)

Luis - please take time to check your facts - providing links to other peoples erroneous blogs is not helpful.

This is a link to SSE's press release regarding the 504MW Greater Gabbard project. The estimated cost *excluding* connection is £1.3 billion or £2.58m/MW. At current exchange rates that is €3.3m/MW.

The other person who replied to you is correct. €0.4m/MW was never a valid figure for onshore wind. It has gone up but it was more like €1m/MW >2 years ago.

The link to the other blog you provided stated that Enersis had wanted to increase the project up to 30 machines - there are three already so this is an additional 27 machines. Ok so its been scaled back by two machines (or was it just rounding in the first place) but it was never 38 machines.

Why are you trying so hard to find fault with this project?

Also is €70m for a first of its kind project really costly? Really? on a €/kW capital cost basis the cost is only 13% more than offshore wind - a technology which has now been deployed in 100,000s (onshore) and benefited from a cost reduction of ~80% over the past 25 years in line with this volume reduction. The market for wind turbines was worth €18bn last year and the main industrial beneficiaries are those countries where the markets where first created - and not countries like the UK for example where the technology was developed but not deployed.

If the same potential exists for wave power this could be a very valuable investment for Portugal, particularly since the subsidised tariff is only paid if projects are successful. The money invested in the project is by private companies not the taxpayer and whilst the tariff is higher than for fossil fuel energy (at present) (but considerably below that paid to solar PV) the cost to the consumer would not even show up above the decimal point on someone's bill. Remember the point here is to invest to get a lower cost source of energy that does not pollute and gives security of supply. How much would you be willing to add to your bill to achieve this?

The proposition that the merits of Offshore Wave Energy can be judged according to the performance of primary deployments of three Pelamis vessels - well to call it hasty would be an understatement.

Moreover, to compare the very first Pelamis' performance with that of the massively deployed Onshore Wind turbines in terms of finance & energy returns further indicates a strange partisanship, particularly as embedded carbon-emissions and public opposition are excluded from comparison.

Outright errors, such as the guess of wave being even more intermittent than wind, when even basic experience of the sea teaches that waves continue long after wind has died away (and sometimes they even arrive from afar without their causative winds) and the mistaken past capital pricing of Onshore Windpower, further diminish the credibility of the critique Luis has attempted.

This is a pity, for Pelamis needs critique as being a cheap & cheerful expedient response to political funding constraints, rather than an efficient converter of a very major energy resource. [Back in the '80s the EU15 commissioned research into the wave energy resource which reported that it could potentially supply 80% of EU15 power requirements].

Pelamis, by its tiny frontage (5ms) compared with its length (450ms) and required sea-space (notionally 2x450 x 2x450 = 810,000 m2 = 0.81 km2) takes up a very large area of sea and length of wavefront per metre of wavefront processed. The latter ratio is around 5 : 900 or 1 : 180. Thus it makes rather poor use of the resource, and would need many serried ranks of vessels (& their moorings) to start getting even a minor fraction of the resource harnessed.

The wave energy tech that has attracted most research worldwide is called OWC (Oscillating Water Column), wherein passing waves are made to rise and fall within a chamber. This allows air above the water to be driven through turbines, with the advantages both of compressibility and of relatively minor containment stresses compared to those of using seawater as the working fluid.
The potential is for many wave chambers to be set in a matrix under a V-shaped floating platform to receive waves sequentially, thus providing high-pressure air in some chambers at the same time as low-pressure air in others, thereby greatly enhancing the air-pressure differential across the turbines and thus their conversion efficiency, while also multiplying many-fold the wave-frontage that is being swept.

Needless to say, this is a proposed concept, not a prototype being launched next week, but I hope that its outline gives some idea of the potential future importance of batteries of Offshore Wave Energy vessels as being one of very few sustainable energies to offer city-scale power supply.
Thus the idea that wave energy should be dismissed on TOD as merely a dubious niche-market option is plainly nonsense, but it may perhaps be of interest for the established "renewable" energy lobbies to try to promote.

In assuming that Luis has been misled by such partisan arguments against Offshore Wave, it is to be hoped that he'll now reconsider.



I wouldn't look that black - or at least it is too early to draw any economical conclusion. This is an early rollout of a prototype waiting for many lessons to be learnt. The electricity plug lesson certainly won't be the last one.
It would be unfair to compare the price of a prototype or a small production with mature technologies: To build a new car prototype may cost millions, but the mass-produced model is much cheaper. Let's see how much prices come down with mass-production of these tubes - if this works then they can be applied in huge masses.
Looking at the project this way and comparing it with other, more mature renewables 13 ct/kwh appears pretty cheap: The price of this technology may come down, whereas the conventional electicity certainly will rise considerably and may even reach this level: The electicity price from coal plant is expected to double if carbon capture and storage (css) is applied (or even more if carbon certificate compensation is needed), and peak coal is possibly only one or two decades ago - the deadly cliff for all new coal plants.

So what do you suggest to compare with? Looking at the Aguçadoura II project scalability is doing very little to improve ROI.

As I commented above, energy inputs are part of the costs of any project like this. If electricity goes up so will the costs. And another thing: why will the electricity generated from wind power be more expensive if the costs are mainly upfront?

Maybe you are right and the concept will fail. But I really think that it is too early to tell that this or similar concepts are not viable (including EROI).

For me these 25 serpents are still a bunch of prototypes - on the long run there could be many thousands.

We had the same prototype failure extrapolation problem in Germany: In the 80s the first modern wind turbine "Growian" was built.
At that time it was the largest wind generator worldwide (3MWp), but soon several technical problems appeared so that finally the expensive prototype failed to work. This served as a proof for our energy industry that wind energy is not viable, which blocked wind energy development and investments for many years before new, smaller scale prototypes picked up again.

So maybe also Portugal is just an early adopter of a technology with a long way to go.

But I really think that it is too early to tell that this or similar concepts are not viable (including EROI).

Read carefully the post, I haven't issued any opinion on the concept.

For me these 25 serpents are still a bunch of prototypes - on the long run there could be many thousands.

Why would I want to pay for thousands of energy sinks?

Thx for elaborating on this Luis.
I have little to add other than "Houston, we have a small problem ...."

Just like a few other posters have said, it is too early to take cost estimates of a mature wave technology seriously. A lot of effort, such as design, testing, and developing systems to manufacture and maintain the technology doesn't scale down to small installations. That is the reason subsidies, or government R&D funding makes sense. It is a public investment in a high risk venture that might have large long term benefits. Any really new, but risky energy venture is going to be like this. You start with a handfull of small relatively high cost experimental facilities that have to run for years before enough experience accumulates before it is possible to make reasonable predictions about the cost effectiveness of mature technology.

I had thought that load factors for wave, at least for prime locations were supposed to be more like .6 to .7. Perhaps the site was not chosen to maximize this, as the primary benefit of the early systems is data and experience, any power generated is simple gravy. As mentioned above, waves can travel thousands of kilometers and days away from their sources, the variability and predictability should be better than wind. Also the variability of wave should have low correlation with wind and solar, so that reliability wise they complement each other.

The Aguçadoura II project is a large scale venture, pretty much outside the conceptual experimental facilities you suggest.

Any reference on those load factors? Check the comment by joule down thread.

Luís, 0.12cent/kw.h is highly subsidized, and does no reflect the real cost.. but it will no stay so low for a long time, maybe after the elections...

Portugal have a large potencial in tidal energy, and it will be cheaper as time passes, with iniciatives like this, i´m proud of our government;)

0.12 € per kWh is very much above wind energy costs at the moment (~0.04 €/kWh) and above the newest generations of thermal solar systems being built in the country (4 years to break even with the feed-in tariff).

I'm not proud of any government that has a target of reducing CO2 emissions in 30% until 2020 and at the same has no program for the Transport sector apart from building more highways and a new mammoth airport.

We need an Energy Policy to address energy scarcity not energy galore.

While a new mammoth airport and all the highway spending are a disaster, this project is not.

1 - You can (and should) address both questions: energy conservation and production
2 - Yes, this project is immature, of course it is, but that comes from being early adopters. It will fail? Most probably. But the lessons learned (assuming people will try to learn) will be invaluable.

Either you want to be in the forefront (and that requires the ability to accept a large amounts of failure) or you trail (wait for others to test things, suffer the failure - but also learn from the experience which is really an edge).

In energy issues, trailing is not an option.

Will this cost a lot of money to the tax payer? Sure, but I am good with that. Just divert some of the money for the mammoth airport to here.

This is a start (as with all starts, it will be bumpy). The airport is a dead end.

1 - You can (and should) address both questions: energy conservation and production

Could you explain how this project is addressing energy efficiency?

But the lessons learned (assuming people will try to learn) will be invaluable.

For Scotland and Pelamis Wave Energy I'm certain they will.

Either you want to be in the forefront (and that requires the ability to accept a large amounts of failure) or you trail (wait for others to test things, suffer the failure - but also learn from the experience which is really an edge).

Yes Scotland is in the forefront of Wave Energy technology. But what about us? How can paying private foreign companies to cram our shores with energy sinks be the forefront of anything good?

Will this cost a lot of money to the tax payer? Sure, but I am good with that.

I'm not. One day this careless wealth transfer from to rich to poor will simply go very wrong.

With peak oil in sight any airport project is sure to become a financial diseaster: The fuel supply decline will be much faster than any progress in efficiency and there is no viable alternative technology for air transport in sight.
So from a rational view I think the best short term solution for London Heathrow would be a controlled downscaling of Heathrow as soon as the number of passengers goes down. And the long term solution (as long as there is no technological quantum leap) will be: no airport. For those few who will be able to afford air travel small planes will be sufficient, for example seaplanes that can land on the river Thames, or things like the more fuel efficient Ekranoplans.

The real progress from marine renewables is going to come from low head tidal / wave over-topping devices. Something like WaveDragon
Combined with low head tidal lagoons as sea defence in certain areas. Would also provide lots of potential for pumped storage.
Build tidal current turbines and offshore wind turbines on the same structure, create some no take zones with artificial reefs nearby.
Farm seaweed/algae as fertilizer/bio fuel feedstock.
Reusing old wind turbine blades for tidal current might be a good idea as they would be more than big enough.

Wavedragon looks sort of delicate. Think about it after being immersed in seawater for a few years, plastered with barnacles and sea squirts and other biological crud. Will those turbines still be turning? With the same efficiency?

Then think of a Pelamis plastered with barnacles. It should still work.

If an energy source needs indefinite feed-in tariffs that suggests (to use a boxing analogy) it is punching below its weight division. If wavepower contributed 1% of the kilowatt hours but cost 5% of total electricity charges that is problematic long term. Taxpayers or other electricity users are paying too much. The tariff could be justified as startup help but needs to be phased out when the technology is mature. The usual suspects will say wavepower increased x% much faster some other technologies therefore it is the winner.

I was wondering how steady the electricity from these devices would be. Does it come primarily from the tides twice a day? If so, it seems like it would be hard to generate enough electricity to pay back the cost? Does it vary with the wind, as you seemed to suggest. Them it would seem to amplify the variability of the wind generated electricity

If it is too variable, it seems like it is difficult to use much of this kind of power without having some sort of backup storage. If this is the case, back-up storage should be considered as part of the cost.

Gail -

Wave power and tidal power are two very different entities.

Waves are just that: regular and periodic disturbances in the surface of the sea caused by wind effects, often from many hundreds of miles away. Wave power is indirectly a form of solar energy, as the sun causes wind, and the wind causes waves.

Once you're beyond the shoreline breakers, the offshore waves can be quite large and steady, though they might not look it. What is not commonly recognized is that the height of a wave (its amplitude) is actually a relatively small fraction of the distance between waves (the wave length). This is typically anywhere from 1:30 to 1:50. The reason this might be surprising is that most people's perception of ocean waves is from looking at them from a low angle while bathing near the beach, which tends to visually compress distances. The waves are actually much farther apart than they appear, and are thus much more smooth.

Tides, on the other hand, are the totally predictable twice-daily rising and falling of coast waters largely caused by the effects of lunar gravity. They are not waves, per se.

As such, the two are almost totally unrelated to each other.

The practicality of tidal power is even far more site-specific than wave power, which in and of itself is highly location-specific. Thus, if wave power is inherently limited in scope, tidal power is even more so.

Because waves are regular and periodic they should be more able to generate a reliable amount of power than wind. similar to wind speed, the power in a wave is per the sqaure of its height.

The amount of power available in the wind is proportional to the cube of wind speed.(the amount of air traversing the turbine per unit time is proportional to wind speed and the energy in that mass of air is proportional to the square of speed).

Soylent, thanks for the correction to my sloppy wording.

The real waves you need are deep ocean wind driven waves. There are certain areas which have a lot of steady wind and a lot of steady wind driven waves(offshore wind is more steady than onshore wind). I'd guess that it would be better than wind.

Wind energy is a bit of a pain. About 40% of the time it produces no meaningful kwh, another 40% of the time it produces about half of the total kwh and 20% of the time, it is blowing like crazy and produces the other half the kwhs.

Hourly/ daily wind speed prediction is an area that computer modelers are working on.

The way you balance things is with standby
backup natural gas generation, with storage or by running
energy consuming operations when there is strong wind.

There are two main types of incident waves, surface waves and ocean swell (deep waves originating from hurricanes and other events far offshore e.g. in the atlantic. Ocean swell waves are the most powerful and and most useful (they are predictable days in advance due to their origin).

I was at the Supergen Marine Energy consortium annual assembly at which a Pelamis employee gave a very short run down on how the deployment went, naturally he said very successfully. He mentioned they had seen waves with Hs (mean wave height roughly) of around 4m already. To put this in perspective the Pelamis machines are 3m in diameter and 140m long in total, i.e. as big as several train carriages, but the waves seen were bigger. The Pelamis machines are monitored and controlled from here in Edinburgh despite being deployed off Portugal.

de Sousa writes,

"the financial return on investment (ROI) is close to 1:1. Where that leaves EROEI is not easy to envision, but it might not be that far off."

The financial ROI is poorly-considered. It's not just cost of project vs revenue raised from selling electricity; avoiding catastrophic climate change and reducing reliance on depleting fossil fuels the price of which will only go up over the next decades is of financial benefit, too. Installing renewable energy thus looks a lot like installing insulation, or tasking the police with dealing with drunk drivers, or putting in fire alarms and sprinklers - at first glance it loses you money, but taking a broader view it prevents greater expenses in the future.

But less us imagine that the financial return on investment is below 1:1. Let's imagine it makes no a single Euro over its entire lifetime. De Sousa has not provided anything to support comments about the energy return. Perhaps he assumes that money and energy are always proportional to each-other?

This assumption, wrong as it is, would not be a problem, except that he bases a conclusion on it,

"this [feed-in tariff] subsidy is masking the low EROEI of some of these new energy sources, that otherwise should be preventing ill fated projects from surviving in the market."

He should have stuck with his other conclusion,

"Correctly measuring EROEI and determining how it evolves along the development phase of new technologies will have a crucial role in the Energy Policy of the XXI century."

EROEIs cannot be assumed from financial ROIs. They must be measured. Financial ROIs are important, but they are not the only thing which matters.

For my part, I am sceptical of the prospects of wave power. The sea is just a harsh place to get work done. Seawater's corrosive, and the very power of the waves this thing is trying to take up, that very power can destroy facilities in storms. Oil rigs, for example, require very heavy maintenance. Other renewable energy sources like wind, geothermal, tidal, solar PV and solar thermal, these seem much easier technically to tap into.

But it's worth a try, and we have to measure what happens to determine EROEI. We can't just assume it matches financial ROI - especially if we don't even calculate financial ROI properly.

Kiashu -

Though I have dabbled in wave power, I too am more than a bit skeptical about its prospects other than as a niche application in very location-specific settings.

I also agree that financial ROI and energy EROEI are two very different animals and should not be confused with each other.

As to the technical issue of the sea being a very harsh environment: indeed it is, but nevertheless mankind has been successfully dealing with that harsh environment for several millenia .... in the form of ships. So, I don't that in and of itself is an insurmountable obstacle.

With a financial rate of return equal to 1:1, it is difficult to think the energy EROEI is much different.

Even if there is some efficiency to be gained from a larger scale implementation without the errors from being a start up application, just how much more than 1:1 financial return could be expected? Not very much I am thinking.

Unless someone has a better demonstration, the conclusion is that dieoff is more likely than this conception of salvation. Kudos for the effort, but tough luck.

The ROI of 1:1 is based on a demonstration project making the price high because it includes research and development. Certainly future systems will cost less per MW.

The Aguçadoura I project includes very little (if any) R&D. The technology was bought to Pelamis Wave Energy as is.

The financial ROI is poorly-considered. It's not just cost of project vs revenue raised from selling electricity; avoiding catastrophic climate change and reducing reliance on depleting fossil fuels the price of which will only go up over the next decades is of financial benefit, too.

I study tangible things like energy and currency. The concept of “reducing the reliance on depleting fossil fuels” with energy sinks is not tangible to me.

And make no mistake about it: any time government delivers taxes earned by hard working people to private companies (most of them foreign) without any tangible gain and even with the possibility of prejudice to Society I will raise my voice against it.

So we should not consider risk in our energy portfolio? Surely introducing more alternative power sources reduces the overall risk to security of supply in the portfolio? The real question is whether the risk reduction is worth the additional costs to the portfolio, or whether the same risk and overall portfolio cost can remain the same with a different mix of energy resources. Comparing the levelised costs in isolation may not lead to the most efficient result.

I study tangible things like energy and currency.

How is currency a tangible thing considering that its value can go up or down tomorrow depending on how currency traders "feel" abouts its future prospects?

At any given point in time there's a known and fixed relation between currency and energy. This relation is driven by monetary policy set by central banks.

If the relation between currency and energy is known "at given poit in time" then why would you describe this relationship as "fixed"?. Currency and energy are both numerical quantities so the ratio between them can always be calculated, but this does not in and of itself imply a causal relationship. A hundred GJ will still be 100GJ next year, but a billion dollars may represent something very different. If you are telling me that central banks have absolute conrol of the value of currency I do not believe it.

We know that the EROEI for corn ethanol in the USA is marginal if not an energy sink. I hear that EROEI for sugar cane ethanol in South American is about 8:1, but I am yet to be convinced that it is that high. Oil itself is estimated now to be only 8:1 so it is hard to believe that grown energy could even come close; maybe someone is jacking the numbers for political purposes.

When there are reports of a new source such as reported here, with a approximate 1:1 financial return, can the EROEI be much different. And most importantly, how can anyone conceive that we can survive at our current population numbers by substituting a 1:1 or even a 2:1 rated energy source to replace an 8:1 rated oil supply.

It sounds like this is more a distraction than a solution, and while we should applaud the efforts of those taking the risk and putting in personal effort, the quicker effort is focused elsewhere the better.

"It sounds like this is more a distraction than a solution, and while we should applaud the efforts of those taking the risk and putting in personal effort, the quicker effort is focused elsewhere the better."

I don't understand what you want. New solutions cannot be developed without trying and applying them (including trial and error). Or where do you think is the "elswhere" where effort should be focused?

Has there been any research into the environmental effects of wave power, if it is scaled up? How will the reduction in wave energy affect coastlines and habitats, for example?

Enersis and Pelamis Wave Power took some effort to thoroughly assess this issue. A British environmentalist showed up with a study saying that dolphins would fell in love for the pelamis and would remain swimming around the red things. They would then stop feeding themselves and die.

Professor Sá da Costa, who in 2006 was still involved with Enersis, had this comment about it:

No matter what renewable energy source you try to develop environmentalists will show up against it.

I think, and hope, that the issue is one of scale. Hopefully, there is a scale to renewable projects that are sustainable (including not damaging our ecosystem). We may not get the energy levels we hoped for, so we may have to consider alternative lifestyles that are very different from what we have today.

Or we could just assume that it will all be alright and keep our fingers crossed.

I would like to suggest to follow up this post with some pictures of the action, because the pictures in this post don't look to promising for wave power.

If you click on one of the pictures you'll find this video:

Thanks Luis.
It is about time that someone spoke up about some of these scams, which no-one in their right mind would put their own money in, and that is why they are invariably Government funded.
Instead of this corn-ethanol on the sea project, very high EROI projects like high altitude wind are withering on the vine for want of small amounts of seed capital.

Okay, Dave, I'll bite. Tell me a bit about high altitude wind. I'm not familiar with it. Thanks.

Wind power resources get much more powerful as altitude increases, and is available in quantity in most non-tropical places.
It is far less location specific than any other renewable, save in the tropics where solar is likely to be a good option anyway.

The problem is that you can't build a turbine high enough - you need to be at least over 300meters at sea, or 800 on land.

A very good resource for the figures behind high altitude wind and one approach to exploiting it is available here:

Other work and different approaches are being carried out here:

Makani is funded by google.

Much progress has already been made in the computer control of kites, presently to provide some of the force to propel ships:

Successful development of high altitude wind resources would need a fraction of the materials that windmills need, and would be mass producible very quickly for truly low-cost energy. almost everywhere.
Getting a few million dollars to build the prototypes is currently difficult for most of the players.

I have a general question/comment about the methodology used to calculate the EROEI for this kind of device. Assume that we are talking about production quality units where the design remains unchanged.

EI(initial) = total of:
-- energy for materials (eg mining, smelting, etc)
-- energy for fabrication (welding, machining, etc)
-- energy for deployment (transport to site, etc)
-- energy for setup and testing
-- miscellaneous other initial energy costs

ER(X) = total of:
-- energy generated over average operational lifetime of X years
-- energy used for operational control
-- energy used for inspections, etc
-- energy used for maintenance & repair
-- miscellaneous other operational energy costs

So, after X years, the EROEI is:

EROEI(X) = ER(X) / EI(initial)

Now, assume a rebuild energy cost

EI(rebuild) = total of:
-- energy for materials lost to rust & wear
-- energy for repairing damage (eg dents, etc)
-- energy for replacing subsystems (eg hydraulics, electrical, etc)
-- energy for re-deployment (eg towing to-from facility)
-- energy for setup and testing
-- miscellaneous other rebuild energy costs

So, after 2X years, the EROEI is:

EROEI(2X) = (ER(X)+ER(X)) / (EI(initial)+EI(rebuild))

and generally ...

EROEI(nX) = n*ER(X)/(EI(initial)+(n-1)*EI(rebuild))

I assume that the energy cost of rebuilding a unit is considerably less than the energy cost of initial construction. If that is indeed the case, then the EROEI will increase as a function of time deployed.

IOW, the longer the units are deployed (via rebuilding) the better the energy return.

Comments welcome, especially from people with a marine engineering background. For example, are navigation buoys serially rebuilt in this manner?

calgarydude -

When reduced to its basics, the Pelamis wave power system largely consists of steel tankage, moderately large steel castings or forgings, plus an assembly of mechanical and electrical components. As such, materials of construction and fabrication probably capture at least 85 to 90% of the initial energy input.

Once it's sitting out there steadily chugging out power, there are only relatively small energy inputs related to maintenance and operation (such as towing a unit back into dock for repairs or overhaul). As such, you are quite right in that the longer the useful operating life of one of these sausages, the better the overall life-cycle EROEI.

And that becomes the critical question: how long will these things on the average last in the cold cruel world? While the analogy to a ship might be stretching things a bit, it is not uncommon for ships to last 30 years or more with proper maintenance. So, I could picture a Pelamis lasting at least that long provided there were several mechanical rebuilds in between. Time will tell. If there is a critical flaw in the design, it will make itself known probably sooner than later.

Another key test will be if these things survive several really bad storms without being damaged or losing a mooring.


Thanks for the clarifications.

I'm familiar with hydro installations in Canada that have been in continuous use for over 100 years. And I saw an aquaduct system in southern Spain that the guide said has been working for more than 1000 years.

After 30 years of use, what is the state of the ship's steel? Does it need to be just heated and re-tempered or completely melted and re-rolled? Or is is too pitted wit rust to be useful?

I'm sure that when energy was cheap, naval architects were never trained to think in terms of centuries of use. Expensive energy may totally change the way ships are designed.

calgarydude -

In general, when ships wear out, either through corrosion or fatigue stress, or a combination of both, they are generally scrapped. Just like worn-out automobiles. Only very expensive large warships are fully refurbished, and even that is a cost-benefit decision.

Just like a car, you can't always tell the condition of a ship by its age. One has to also look at how it was used, where it was used, and how well it was maintained.

A ship that had been pushed too hard through many bad storms can suffer permanent structural damage, just as if you drove your nice new car too fast down some bumpy rutted out country roads. Plates get distorted and stay that way. Cracks appear. These can be repaired, but after a point, it becomes a hopeless proposition.

Again, any design is a balancing act among competing values. Do you want to pay a lot of money up front for something that will last a long time, or do you want something cheap that will last only a short time and maximize short-term profit? It all gets down to what the objective is. For the Pelamis I would think that a long life for the structural portion would be a very important criterion. Whereas, the mechanicals would most likely be designed for ease of replacement or overhaul. Minimizing labor must be a top priority. Overall, I think the Pelamis is a good wave power design. If they can only get their costs substantially down, they might have themselves a nice niche business.

Time will tell.

I'm troubled by the quality of the engineering science revealed in this project. A hydraulic ram is a well known hydraulic device, and they are not using a hydraulic ram. See wikipedia for a reasonably accurate description of a hydraulic ram. I do not see any engineering data. I do not see any discussion of engineering design issues that they identified, nor how they were decided. There is no mention of Naval Architecture, which is the engineering discipline dealing with the design, construction and repair of marine vehicles. There is no discussion of sea state. Is the current definition of sea state adequate to record the parameters that are important to the safe and productive operation of these devices? Have they asked this question? Have they thought of this question? Do they even know that a definition of sea state exists?

The energy in waves comes from solar energy via wind energy. There is necessarily less wave energy than wind energy. Will wave energy resource be depleted by full build-out of ocean wind?

In fairness to wave energy, the medium in which the waves exist has a much greater density that air. This results in much greater energy density (Joule/unit volume) than energy density for wind. But can this advantage be captured within a reasonable collection device?

Too much hand waving that shows no knowledge of engineering beyond that known in the time of Aristotle, Plato, or maybe the Iliad.

geek7 -

I fear you are jumping to conclusions.

I think I know what you are referring to in your comment about a 'hydraulic ram'. It is perhaps merely a minor confusion in terminology. Suffice to say that the Pelamis system is based on converting the energy embodied in the relative movement of the four floating 'sausages' via a system of hydraulic pistons. Perhaps one shouldn't call these things 'hydraulic rams', as that term can sometimes refer to a crude water-hammer type device used to pump water uphill. Perhaps this is what you are alluding to?

You do not see any engineering data because the article was a news article rather than a technical article. I have dabbling in wave power a bit, and from all I can discern, the Pelamis system has been well thought-out and well engineered. Whether it will eventually become economically viable without subsidies is another question altogether.

If after a year of continuous successful operation we find that the Pelamis system is still chugging along, would you be convinced that some very careful technical analysis went into its design and construction?

You do not see any engineering data because the article was a news article rather than a technical article. I have dabbling in wave power a bit, and from all I can discern, the Pelamis system has been well thought-out and well engineered.

Joule, have you had a look at the Swedish linear wave generators? It seems like a simpler, more robust approach to wave power. I don't really believe any wave power to be practical, though.

jeppen -

I wasn't familiar with this one specifically, but I believe some Dutch firm was developing something very similar (at least as of about three years ago). This one, and the Dutch device, fall within a category of wave power converters called 'point absorbers'.

These include those designs where a float of some sort is made to oscillate up and down in response to wave action. They actually are capable of absorbing wave energy from a wave front several times wider than the width of the device itself. It would appear that linear electrical generator (as opposed to a rotating one) is made to order for devices like this.

The design appears to have a lot going for it, though it's most
serious drawback is that it is submerged, a feature that solves some problems but also creates others. No doubt it can be raised to the surface by releasing ballast and then towed in shore for maintenance and repairs. However, it is probably pretty expensive to design and build something that can operate submerged for perhaps years at a time.

The development of wave power, if it gets anywhere at all, will probably follow a pattern similar to that of wind power. When people first started dabbling in large wind power systems in the 1970s, there was a bewildering array of all sorts of designs under consideration. However, wind power has now evolved to a point where there is now an almost standard design: the horizontal turbine with three thin blades. We will probably see wave power also converge toward a single preferred design. What that will be is too early to tell at this point.

There can be many reasons why engineering data is not presented. Often when data is not presented there is a reference to a publication where it can be found. In other cases, there is a claim that the data is proprietary or that a patent application is in process. If the presentation was originally written in Spanish, there might be a translation reason for 'hydraulic ram'. I don't speak Spanish, but I venture a guess that ALL Spanish hydraulic engineers read and understand the engineering English of the hydraulic engineering community. They read and understand the commercial catalogs of products of English speaking manufactures.

The problem is deeper than mere confusion of terminology. It appears to me that the presenters of this information believe that they are working a Ponzi game. There may be a real product undernieth the game. There may be some good engineering going on. But where is assurance that if funding gets tight they will not let the engineers go and keep the marketers?

It was a dark and stormy night. Despite its immense size the crew of the supertanker was having trouble using their sea legs. The midnight to 4 am helmsman on duty mistakenly puts a heading of 54 degrees instead of the 45 degrees as ordered. The 9 degree difference sends the ship directly through the Agucadoura II wave farm causing damage to both the pelamis units and the ship.

thomas deplume -

Aye, them wave farms never give up their dead. Arghh!!!

Hell, you can always screw up. With literally anything. So what does that prove? Did the sinking of the Titanic prove that ocean transportation is not feasible?

thomas deplume
must be a sailor like me.
until you live the life ,like me for 4 years, you have no idea , of the power of the ocean.
it's a very dangerous place.

I only commen,t is that maintenance will be way beyond their , estimates.


offtrack -

The sea is indeed a rough place, especially in those locations where the waves are the best, such as parts of the North Sea or those areas of the UK facing the open Altantic. That's why any commercial wave power system must be exceedingly robust if it is to be a success. Some of the earlier experimental wave power systems were pounded to pieces.

You can't be hauling these things back to the dock for repairs every time there's a bad storm. If I had to guess, I'd say that from a maintenance and repair standpoint the weak point of the Pelamis system might turn out to be the supports that hold those hydraulic pistons in place (or even the pistons themselves) as they are subjected to repeated cyclical stresses.

I know that in the NorthWestern US, they end up replacing/seriously repairing quite a few of the navigational/weather buoys every year because they break/break loose/sink/whatever. That said, they expect to have to go around and replace/move/repair/maintain the buoys regularly anyways, (for instance, the batteries have to be replaced every 2 years even if nothing happens to the buoy at all, and ships keep hitting the things because they are sitting at the edge of the navigational channels, both of which are problems this facility should be able to avoid.) And so while I suspect the buoys could be built to withstand the weather better, the trade off when you already have a coast guard buoy tender in the area, of more expensive/longer lasting buoys vs more often replacements/heavy maintenance just isn't worth it...

Now, has that trade off been made correctly in the case of this facility? I certainly don't know, (and this article didn't help with that,) and I suspect that the people that built it only have a rough guess, and they'll know more in a few years.

The 9 degree difference sends the ship directly through the Agucadoura II wave farm causing damage to both the pelamis units and the ship.

Or the submerged rock

Or the dark coastline peninsular

Or the oil tanker offloading offshore

Or the offshore wind farm


Where and how did you calculate the EROEI? You stated...
Where that leaves EROEI is not easy to envision, but it might not be that far off.
And from there went to...
Even if Pelamis manages to deal with low EROEI

Which is a bit confusing. If you accidentally left your EROEI calcs out I'd love to see them, however if you are assuming EROEI is proportional to cost, especially for one-unit demonstration projects, I think you may want to calculate the project's EROEI just in case that assumption does not hold. Also I think that looking at emergy as opposed to energy if you already aren't would be a good idea since renewable power sources that produce electricity give us an energy source with a very high exergy and few externalities, unlike those of fossil fuels, which we have to deal with later via greater health care costs and more frequent natural disasters, among other impacts of course.

I wonder whay the best wave power rigs dont get funding?
Pelamis can not easely be combined with wind mills.
Wave Dragon and Ocean Wave and Wind Energy can be hybrid wave and wind farms, and energy cost will be even cheeper than wind mills alone.