Excellent analysis!
In the SW United States and Texas, the drought is killing off many hardwood trees, such as oaks, furnishing plenty of wood to burn. Many 400-hundred dead live oaks are evident across the Texas Hill Country due to a fungus and perhaps weakended by by long term drought. Mnay ranchers would welcome a market for there dead live oak trees.

When totally dry, sewage sludge has about 4000-7000 Btu/lb, which is equivalent in heat to lignite coal.

That last graphic, "Years of Heat in Standing Forest", tells the whole story. The SE US, upper New England, and the Pacific NW are the places were wood has the potential to carry a significant portion of the heating load. To my way of thinking, it does not make sense to transport firewood long distances (that requires a lot of energy, too), those places that are near the forests and need the heat are the places where wood heat is most feasible.

I suspect that if the data were availabile to break this state-by-state analysis down to a county-by-county analysis, what you would find is that it is particularly those counties in and immediately adjacent to the mountainous areas of the SE US, Upper New England, and the Pacific Northwest, that are particularly favorable for wood heating. It is in the mountains, of course, where the trees are, the land not being favorable for farming. Populations tend to be less dense in mountainous areas as well. I suspect that a few other areas would also be favorable on a county-by-county analysis: Central PA and Upstate NY, The Ozarks, parts of northern CA, parts of Southern IN & OH, and a few other places. There would also be places in the SE US, Upper New England, and the Pacific NW that would drop out, being too flat, unforested, and overpopulated.

Of course, population density is also an issue. In a small town like mine in the Southern Appalachians, surrounded by massive hardwood forests, it makes all the sense in the world for many people to be burning wood. If everyone in Atlanta would try to do that, though, I don't know if breating would still be possible.

I have been heating with wood most of my life here in the SE. During the winter I also cook and heat water with wood. i use only hard wood and never use wood that has been seasoned less than two years. While my wood heater will heat most of my 2000 sq ft. home if i turn on the air handler from the central air to distribute the heat generally I just heat a 6oo sq ft room where everyone seems to congregate during chilly weather. The great advantage to a wood heater is that folks just seem to gravitate to the warm space around the heater, making it unnecessary to heat the entire house. Sleeping in a cold room is something everyone should get use too. I should note that it takes many years to learn to operate a wood heater correctly. I use a minimum of three thermometers at various places on stove and exhaust pipe to constantly monitor temps to insure efficient operation. Stove and pipe maintenance is critical. Wood stoves are extremely dangerous! While i have a wood lot on my small farm I get most of my wood from discarded wood from power line clearing operations and from neighbors who cut down damaged or unwanted trees.

Excellent post Nate, one of the main concerns I see with peak fossil fuels is the rush towards biofuels making the problem of soil depletion & CC worse by removing carbon sinks and intensivly farming biofuels. I think a far better solution is to; move towards high insulation standards making use of solar gain,
Where homes are not on the gas grid make use of local wind resources and electrically driven heat pumps, I make it about 2.5 quads from non natural gas heating, using a COP of 2.5 for the heat pumps means we require 1 quad of electricity which is about 300,000 GWh according to http://www.ecoglobe.ch/energy/e/index.htm.

For wind turbines each MW of capacity will generate about 2.5GWh a year (0.285 capacity factor) which gives us 120GW of installed wind capacity, roughly 5 times the current capacity (~25GW) the US installed 8GW last year so allowing for 25% a year growth (quite high but the last few years have seen growth of around 20-50%) all non gas heating can be replaced with wind powered heat pumps in 7 years. Of course if you cut heating demand by 20 or 50% with passive solar techniques, insulation) this number reduces to less than 6 years or less than 4.

The roll out of wind turbines and heat pumps along side each other would also help overcome the variations in the output of a wind turbines allowing the electricity to be stored as useful heat inside buildings without any round trip losses from storing the electricity. With frequency response and other 'smart' control systems (most likely through some sort of internet or local radio connectivity) on heat pumps and electric battery charging, it should be possible to get lots of renewable energy sources onto a grid.

Modern woodstoves have efficiency of about 80%.

With a combination of superinsulation, heating only a portion of the house, smaller residences, use of passive solar elements where appropriate and so forth, it would not be very hard for the U.S.'s total home heating use (in btus) to fall by 80% over a period of three years or so. People just have to decide to do it. Over a longer period, allowing new construction specifically designed for low energy use, a 90% decline is entirely possible in my opinion. 90% is an additional 50% decline from 80%.

Like other renewable energy sources, wood energy is best analyzed in a local or regional context. Macro analysis is of limited use. It also helps to bring some background knowledge to the task of analysis to avoid distortions in the results. For example:

"(Due to larger amounts of creosote and much lower wood fiber density in softwoods, they are not suitable for conventional firewood and I assumed are not used for heating –in a more advanced analysis this assumption could be relaxed as people could harvest softwoods and replant with hardwoods at least to some extent and/or install external wood burners)"

First, creosote is not a component of wood but a byproduct of incomplete combustion. Second, people living in large parts of western and northern North America have only conifers like fir and spruce and lighter deciduous species like aspen to burn and they make out fine. Softwoods are widely used for home heating. Half of the firewood I burn is poplar/aspen, which has about the same density as spruce. Third, it is a mistake to assume that hardwood (deciduous) trees can be planted to replace conifers or even that this would desirable. Note that advanced technology residential heaters of the kind that have been available for twenty years can burn softwoods just fine. The idea that only hardwoods make good fuel is traditional knowledge that is no longer valid.

"Freshly cut wood has over 60% moisture and therefore takes much more effort to release the energy in the wood fibers. Seasoned wood approaches 20% moisture content"

You need to be careful which method is used to express wood moisture. Using the wet basis, the normal moisture of live trees ranges from 30 per cent to somewhat over 50 per cent. The ideal firewood moisture content is 15 to 20 per cent.

"Wood stoves and furnaces average about 55% efficiency."

While that is true for old style conventional stoves, the advanced, EPA certified stoves average around 70 per cent efficiency.

But the main problem I have with the article is the underlying straw man argument, namely: If everyone heated with wood the forests would be gone and the air would be too polluted to breathe. That is certainly be true in relation to the forests, but then no one has ever suggested that wood is a suitable fuel for everyone everywhere. Like the other renewables, wood is a local fuel and when considering its potential, it is best to analyze it at that level.

Also, dense smoke emissions are not inherent when wood is burned. Using EPA certified stoves greatly reduces smoke emissions. But wood is still a lousy fuel for large urban areas, partly because of air emissions but also because the cost of fuel transportation and storage make it impractical.

Hi. Just continuing the debate regarding the efficacy and efficiency of wood as fuel with my new video...http://www.youtube.com/watch?v=AKdxJ8X8c0M&feature=channel_page

Pellet stoves sales have been exceptionally strong in recent years, but there's a dwindling supply of wood pellets and their price has increased sharply -- now running in the range of $6.00 a bag versus $3.50 just a few winters ago. It seems unlikely the situation will improve anytime soon.

See: http://www.bangornews.com/detail/99407.html

On this side of the border, police had to be called to break up a scuffle at a local hardware store when rumours spread that a tractor trailer load of pellets was about to be received.

On a related note, nine out of ten homes on beautiful Prince Edward Island are heated with oil. Earlier this fall, PEI's CBC evening newscast, Compass, ran a four part series series entitled "Escape from oil", accessible at: http://www.cbc.ca/canada/prince-edward-island/story/2008/11/13/pe-f-ener...

For more information on the Cansolar panels featured in the fourth segment, "A bright idea", see: http://www.youtube.com/watch?v=n7L013AAhR0&feature=related

Cheers,
Paul

I am living in Scandinavia and not so familiar to the feet-stone-gallon-cord system. However, growth in forest in the metric system is usually measured in cubicmeters "with no air inside". When splitting wood you get air between the logs and you get "more" cubic meters of stacked wood due to the air inside the stack of wood. The difference might be as much as 1.6-2 times in volume depending size of the logs.
To me it was not obvious if this was taken in account in text.

A lot of forest is grown primarily for saw logs and pulp. Fire wood comes as byproduct of that. If for instance spruce is replaced by hybridaspen or hybridpoplar growth can increace by 3-4 times and 4-5 times. This gives harvest cycles of 20-25 years for hybridaspen and 13-18 years for hybridpoplar. If you live further south of Scandinavia you can use other trees that yield even better.

Interesting. Sustainable energy is the future no matter how you look at it.

Some facts about wood:

On average, a natural forest (not grown by humans) can sustainably produce 2 tons of wood per acre per year. A human grown and managed forest can produce upto 5 tons of wood per acre per year.

Each kg of dried wood (20% moisture) contains 20 MJ energy. Therefore one acre natural forest can provide 40 GJ energy per acre per year.

A quadrillion is equal to 1 million billion or 10 power 15.

To get 7 quadrillions of energy that the article say is used by usa to heat homes there is a need of 175,000 acres of forest. Given the size of usa its not a large amount of land.

I can't be wrong about each kg of wood providing 20 MJ energy as I had found that on many sources and as one liter petrol is about 33 MJ, one kg hay has 2000 digestible calories or 8.4 MJ digestible energy, one kg wheat has 3400 digestible calories or 14.28 MJ digestible energy, one kg coal has about 22 MJ energy etc (some examples of organic stuff).

I also can't be wrong about 1 acre producing 2000 kg wood per year as 1 acre is a pretty much large piece of land having 4000 sq m land and in natural forests 160 trees per acre and in human-managed orchards 400 trees. There can easily be 160 trees in one acre in a square format with a distance of 5 m between trees. At 160 trees per acre there should be a 12.5 kg wood per tree per year, given density of wood as 0.6 gm/cc it means a cube of 27.5 cm on each side (one hand plus one third hand).

Note that I am counting branches and fallen pieces of wood too that are of not much use in furniture making but are good enough for burning.

Btw I also found out that one acre of natural forest also produce 600 kg fallen leaves (ofcourse mostly in autumn). These can be fed to goats to get an equal amount of solid waste, solid that is other than urine and moisture according to the law of conservation of mass.

GROWTH IS EXCEPTION, NOT RULE

In Sweden, wood pellet furnaces have almost completely replaced fossil fuel furnaces, in areas without district heating. The furnaces are at least 80% efficient, many claiming 90% efficiency. Wood pellet energy content is high, about 7450 BTU/lb, since moisture content is below 10%. The pellets are made from sawdust and other waste. While they do require some energy input in refining, they enable use of a resource that would otherwise be wasted.

It would seem that wood heating will never be as thermodynamically efficient as geothermal-assisted heat pumps.

And that wood can be converted to bio-coal, with electric power co-generated during the conversion process, resulting in a readily transported, readily stored fuel that can be used to fuel dispatchable power to complement volatile "use it or lose it" power sources such as wind turbines, CSP, run-of-river hydro.

Of course, whether using firewood or biocoal, directly or via the grid, its only sustainable renewable energy if the wood is grown in a sustainable, renewable fashion. The most appealing approach for that is coppice wood production, where the tree is cut back down to leave just the main stems, but the root system is left intact, so that it grows out again much more effectively than planting seedlings.

And with coppicing in rows along a level elevation, so that for a species with, say, a 5 year harvest cycle, one out of 5 rows are harvested each year, it is possible to "farm" coppiced wood even in the hilly terrain of Appalachia.

I realize there is lots of state and Fed forest land. But there are also many small holdings like mine (57Ac). Would it be worth it to me to log my land for firewood? Let's say I got 50 cords at $300/cord - $15k. My answer is no, with the reservation below. In my area there is about a 40 year cycle of harvest to harvest so this would, essentially, be a one shot deal. I would be left with denuded land and a lot of work to re-establish the trees.

However, if George Soros and others are correct that there is no bottom to our financial quagmire in sight, I could see having to do at least some additional harvesting beyond personal use for either barter or income. Even this assumes fuel is available for saws, splitters and trucks. At the current price, doing it by hand is unrealistic.

Todd

Softwoods are used for firewood wherever hardwoods are scarce. You just have to clean your chimney a little more often. A cord as actually sold is about 90 cubic feet of wood and 38 cubic feet of air. I use about 300 cubic feet per winter to heat my house, which has had five inhabitants, but is now down to my wife and I. All of it, and most of the wood used in my part of northern California, is mortality. Most of this year's wood was lodgepole pine. In theory, the annual growth in the United States of 23.7 billion cubic feet could heat about 75 million homes like mine, but I agree with comments above, that the last graph shows where wood heating is feasible for a large percent of the population.

I think the whole point of the article is that wood heat is just not sustainable.

There may be small pockets of sustainable wood heat in the U.S. but generally speaking wood heat will result in total deforestation of the continent.

When I try to raise the spectre of peak oil and it's consequences most people always pull out the cunard about wood heat. Thank-you for clarifying for me the consequences of believing wood is a viable alternative.

I heated with wood for 20 years. It took me five years to learn how not to burn down my house. Imagine the carnage that would ensue in a large shift to wood heat. And I suspect most people new to wood heat would use softwoods. The creosote build-up would be horrendous. The chimney fires catastrophic.

For those looking to burn wood more efficiently try:
www.woodheat.org/
I just ordered some wood yesterday. Most of it oak and compared t o elm it has burned longer with fewer trips out during the day. I recommend a mix of soft and hard wood for efficiency. As for pellet stoves I think the distribution issues will become a factor soon. You can always burn your furniture in a pinch. Pellet stoves also require electricity to run. This is not very helpful in a blackout.

I am posting some content that was recently circulated around here by the FSA and Extension Agents regarding damaged trees.
********************************************************************
Trees that have suffered extreme damage may not have lateral branches remaining. Without laterals the only choices are immediate removal, making topping cuts with plans to replace the tree within a couple of years or making topping cuts and accept liability into the future. Topping cuts are never recommended for the long term survival of any tree. Even though some new growth will develop at the point where stubbing cuts was made, decay will occur and in conjunction with the colunmn of decay in the trunck will suffer significantly higher rates of breakage in the future.

Tree species differ in their reaction to ice loads. River birches,silver maples,oranmental pears,white pines,willow and many other species suffered disporportionally more damage from the ice storm. These species grow rapidly, reproduce early and are short lived. Other trees like bur oak are long lived. They invest their energy reserves in slower growth that is more durable with reproduction starting at a later age.

The Easter Freeze of 2007. Some tree breakage can be traced back to another mean trick of Mother Nature. It will be two years ago this April that we experienced a record breakihg plunge in temperatures just as we thought spring had arrived. This freeze caused trunk and branch cracking, especially in young trees so that they were too weak to withstand the effects of the recent ice storm. It also killed some or all the flowers on many of our trees. As a result they produced no fruit in the fall of 2007. In 2008, these trees overcompensated and with the help form a good pollination season produced abundant fruit.
On trees like ash and crabapple, these fruits persisted well into the winter, adding to the accumulated weight on the branches during the ice storm.
*******************************************************************

Now most of these is in regard to homeowner and orchard plantings.
But there are some takeways. Lateral branches are important. Topping cuts and trying to prune is likely a waste of time. Many of the forest trees therefore are lost. Those who are native to the area may survive but never like before. The huge very old white oak I have always favored in the woods close to my houes and where I buried my favorite hound has lost huge amounts of lateral limbs. Yet the top is still there. The report further states that new growth as a result of limb loss will never be very strong or worthy. This part was embedded further in the lenghty newsletter.

I fear that much of our woodlands are in deep trouble.

The other takeaway is that nature is capricious yet we have done our part to destroy the environment horrifically. Nature is repaying the debt. It is being unpredictable. In the last several years here I have no memory of some of the events that have occurred in that time. Floods,rains,lost crops,wet springs, cold falls, and now three whammies in a row. This being the worst.

As our trees fall and are shorn the winds will raise havoc with the soil Already a lot of roofs were blown off three years ago. Mine included. The patterns are changing. They are not getting better. Farmers are not helping by dozing down woodlands and fence rows to get more crops yields. Given free rein I think they would destroy every tree in sight. I know one fat farmers ahole who brags, "I would rather cut a tree than eat a meal!"...I say that he has missed very few meals but he has cut a lot of trees. My dad sharpened his chain saws. He is an imbecile. He is not alone. The government programs that used to tout conservation is no longer a voice that I hear in this land. They have gone silent on 'sod busting' as well.

Airdale

Softwoods can provide fuel in the form of pinecones which burn rather quickly. It's easy to collect a couple of buckets of them. I'm not sure what they do with all the throwaway newspapers but surely they could be made into slow burning pellets.

Right now it's summer in southern Australa and I'm cutting and stacking heavy eucalypt branches that have fallen in storms. In winter those storms consist of sleet and can last for three weeks. Last July for example I guess I would have used a tonne of wood. This year I intend to experiment with heating a smaller volume of air using removable curtains as room dividers. I'll also get a carbon monoxide detector that gives warning beeps.

Note this is all because I have free firewood and I suggest it is not sustainable long term for a large population. Fires generate particulates, tars, fire hazards, smoked out neighbours and general respiratory distress. Smoke stinks up your hair and clothes. Stumbling around with axes and chainsaws invites accidents. In a perfect world we should all have passive houses with sparingly used heat pumps powered by low carbon electricity.

Home heating with wood?
It's not hopeless if everyone decides to live in Passive Houses.

There are 150 million dwelling units in the USA. The average area is 1500 sq. ft or 150 m2. A typical Passive house uses ~30 kwh per year per m2 for domestic hot water and ~25 kwh per year per m2 without considering solar space heating.
Cooking is not included here so the total is 55 kwh per year per m2.
So the total is 150 million x 150 m2 x 55 kwh per m2=1250 Twh.
The efficiency of a pellet stove is ~80% so we need ~1500 Twh or 5 quads of energy--5 quadrillion BTUs divided by 13 million BTUs per ton of pellets= 385 million tons of pellets.

North America currently produces about 300 million tons of roundwood(trees) used for lumber, paper, pulp, etc. This is 80% of what is needed but really pretty close to what the US
would require if all houses were Passive Houses.

So it is certainly theoretically possible, IMHO.

One of my concerns is that not only do the cellulosic ethanol folks have their eyes on wood, but also the folks who want to replace coal for electricity with locally grown wood. We really don't have enough wood to do all of these things. They may sound renewable, but they aren't really, on the scale that folks would like to do them.

Yes, clearly wood burning can only be one part of any future sustainable way of staying warm in the winter. My first vote is for super-insulation and passive and active solar.

And of course lower indoor temps, especially at night, big comforters and efficient sleeping bags, more people per bed (oops, never mind), more people per square foot of living space, heat exchangers, geothermal...

The problem of particulates is quite a problem in urban areas, but also in mountain valleys where you easily get inversions.

In general, people tend to look toward the next thing they can burn, rather than thinking about other changes that would make it less necessary to burn anything (or much of anything).

I live in Minneapolis and remain on the fence about whether to get a wood burning stove. Even the most efficient ones are going to increase the levels of particulates my family and neighbors have to breath. We recently defeated a plan to have a wood-burning power plant built near by. The issues of particulates and of what else might go in when good wood was not affordable or available were of primary concern (along with shady dealings that seemed to be going on behind the scenes).

Have others dealt with similar issues in their cities and towns?

The other big problem with wood stoves is they release massive amounts of particulate pollution.

Gail's post is a reasonable analysis of using forest cut wood for heat.

But, what about using "waste wood" for heat!

The pie chart of annual wood usage shows nearly 1/2 of all wood going for "saw logs". Much of this is lumber for houses, but a good portion of this is for things like shipping crates, pallets, construction off fall, scrap from milling and cabinet making, etc. This country throws away millions of tons of waste wood every year, most of which gets buried in landfills.

The company next to mine at an industrial complex in Granite City, IL throws away about 5 tons of junk pallets every week. I see other companies in the area likewise filling 40 yard dumpsters with waste wood every week. My shop did have a non code wood heater that burned waste wood.

For nearly two years I used old pallets and wood scraps from the trash to heat a 3000 sq ft. shop. All that heat for no $$$. CO2 from my buring wood did not contribute to GHG since the wood decays to CO2 and maybe CH4 (even worse) in a landfill. My stove produced no visible smoke and had a chimney exhaust temp low enough that I could hold my hand 12" above the outlet and not get burned (flue gases and exchange air gases were almost the same temp. meaning great efficiency).

So my question is this:
How much could waste wood contribute to heating our homes?
Perhaps 10% of our US homes could be heated with waste wood products if this material was kept out of the landfill stream (IMO).

The intent of the article might be to show that wood heating is unsustainable but what was really shown is uninsulated houses are unsustainable. Insulating takes time and money. So does firewood.

Having worked as a chemical engineer in the pulp and paper industry for over 25 years, here are a few thoughts:

Wood waste such as sawdust, bark and other sawmill wastes are typically the cheapest fuel available. That is because there are few boilers or furnaces that can easily handle such material. It also requires bulk material handling equipment such as front end loaders and bulldozers and conveyors. Pulp and paper mills are equipped to burn this material for steam and power and can do so with very low air pollution. Wood ashes are valuable fertilizer that the industry does not recover. They usually end up in landfill.

Some of this wood waste material is now going into pellet fuel.
There is no real surplus of wood. Any additional wood consumption will compete with pulp, paper and lumber.

If there were no other uses of wood, we still could not heat 100% of our homes. However, there is room to improve forest yields. Private landholders, who own most timberland, are very inefficient wood producers compared to managed plantation forests. Managed plantations are declining because states have raised taxes on land and the standing timber inventory. Whenever possible, timber companies sell land for development to make ends meet.

Not having to cut firewood and manage a wood stove are features that define our standard of living. Cutting enough wood to heat a home requires the kind of time working people seldom have, although the exercise would do them some good, at least for those who don’t hurt themselves. This time would be better spent building a new ultra energy efficient house with a geothermal heat pump. Using natural gas in a combined cycle plant at 60% efficiency to produce electricity to power a geothermal heat pump would reduce heating energy by at least 60% compared to burning it in a home furnace.

In making paper, which uses the cellulose or fiberous part of the wood (except newsprint, which is all wood) the last water to evaporate in the drying process is called bound water, which takes extra energy to drive off. To accomplish this for firewood you would probably have to hold it at a temperature above 220 F or 105 C for many hours, which perhaps could be done with a solar dryer. Removing this water should add several percent to the heating value, and make the wood burn much faster and hotter. Has anyone tried this or read about it?

I once read a quote about a slave in America having more firewood than a nobleman in Europe. Can anyone tell me the source?

Reading all this got me looking around on the net about heating, and I found this really COOL site on rocket stoves, heating in general, considerations in heating high-mass vs. low-mass houses, etc.

Lots of cool stuff on stove design.

http://weblife.org/capturing_heat/

My property is along a river in New Mexico and is wooded. It is a Fremont cottonwood riparian bosque heavily invaded with Siberian elm, Russian olive & Tamarix. I occasionally cut fallen cottonwood limbs if they're in the way but don't kill the native cottonwoods as they have poor recruitment due to competition with the invasive species and I seek to preserve them. I heat with wood from the invasive species, in a homemade fireplace insert. I cut the wood with a Husqvarna chainsaw and haul it up to the house in a wheelbarrow. I'm in the market for a pony or donkey for pulling a wood hauling cart. The optimum length for my firebox is 28" and I try to cut it close to that length to minimize use of the chainsaw. A year ago I broke down & bought a hydraulic log splitter, since I'm not as young as I used to be for swinging a sledge. Unfortunately, 26" is the maximum length that will fit in the splitter, so I cut rounds that need to be split 26" & those that don't need split 28". We have burnt four cords so far this winter and still have about six weeks of wood burning season to go. This is more than we've burnt in past winters because my wife isn't currently working so she stays home & keeps a fire going all day. The fireplace insert isn't too efficient but efficient modern woodstoves are expensive. The fireplace heats the main part of the house very well, altho even with an electric fan blowing warm air down the hallway the bedrooms aren't very warm. I sleep in a sleeping bag during coldest winter. My son and I are cutting next winter's wood this winter. We let wood cure for one year before burning it. Virtually all the wood we burn comes off the property, altho I may get a permit from the BLM or Carson National Forest and haul in some juniper or Gambels oak. I claim that the wood harvesting off the property is sustainable and this is true with the following caveat: I am depleting the larger trees. Many smaller ones are growing, keeping biomass about the same, but the larger diameter trees are becoming more scarce. Most of the families in my neighborhood heat with wood, altho probably not exclusively. This is my woodburning story.

Just a couple of comments on a good analysis.

The portion of wood that is currently going to pulp/paper is decreasing as the world goes more electronic. In a peak oil world, this trend would likely accelerate since the world economies would shrink and less money would be available for printing. Similarly, peak oil would reduce amount of wood that would be used for building homes because people could not afford to build large houses, and new home construction would diminish. This woody material could then be available for heating.

Homes could be made much more energy efficient thus dramatically reducing the amount of heating required.

The least capital intensive means for combusting forest material would be in fireplace inserts or wood stoves. However, if the woody material could be burned to produce electricity (assume 40 percent efficient), and that electricity was used to run ground-sourced heat pumps, which are on the order of 400% (or more) efficient for heating, then wood could supply a much larger fraction of heat demand (perhaps three times more). Also, there is a lot of forest residue (small branches) which would likely not be used for home heating, but could be used for electricity generation.

If trees were grown in plantations, which is bad for biodiversity, but good for producability, then forests could could be much more productive.

I suspect that if you did the math on these factors, that the woody material could be used to heat all our nation's homes.

This all ignores the likely future use of forest material for liquid fuels, which would compete for resources with home heating.

Retsel

We just had our oil tank topped up a few minutes ago. Since our last fill on October 24th, we've used a total of 160.6 litres (42.4 gallons), which is an average of 1.32 litres per day (0.35 gallons). Roughly half this fuel was used for backup support for our two small heat pumps and the balance for domestic hot water production (approximately 2/3rds of our DHW is heated with electricity and 1/3rd by oil).

Over the past 300 days, we've used a total of 312.8 litres, which means we're on track to getting our demand below 375 litres/year. When we bought this home in April 2002, it stood at 5,700 litres, so we've cut our fuel oil consumption by nearly 95 per cent thus far.

I was hoping we could have done better, but this winter has been considerably colder than last (several days with below -20C temperatures) and we had to run the boiler to supply heat during the four weather related power outages we've encountered so far this season.

I mention all this because so many people tell me heat pumps don't work in colder climates and I'm here to tell you otherwise. So what about our electricity consumption, you might ask? It has gone up since we added the second heat pump and the electric water heater; over the past 368 days, we've used a total of 11,671 kWh and as we roll into the next billing cycle we'll likely exceed 12,000 kWh. If all goes well, we should be able to get back below that mark as we move into the summer months. Come spring, I'll run our heat pumps in dry mode which I expect will use less electricity than our dehumidifer and I'll start washing our clothes in warm or cold water if need be.

For those who may be interested, our consumption history for the past 14 months is listed in the lower right portion of our latest bill:

Cheers,
Paul

We heat with wood. We use highly efficient wood burners sometimes called finovens. They are about 90% efficient and produce about 2% of the pollution of standard wood burners (for the same heat production) in Holland they can be found at http://www.tigchelkachels.nl/?pag_id=1584&site_id=31
in France: http://www.poele.com. We prefer the way they function over that of a standard wood burner, you make a very fast burning wood fire which burns in about 70 minutes. You close them up, and they stay warm for the next 12 - 16 hours. Because they are optimized for good combustion, soft woods can be burned without any problem. I never have to sweep the chimney, just a yearly vacuuming out of ashes and particles which have fallen down the flue. Minimum weight is about 800 Kg (heavier versions can stay warm much longer between fires). Once the fire is out the combustion chamber can also be used for baking.

This said, our insulating budget is currently about 700 euros/year and it looks like it will continue at that rate for the next few years. Our next investment in heating will undoubtedly be trombe walls, passive solar and insulation are the best possible heating.

Cut down all the damned ornamental pear trees and plant some real fruit trees - two birds with one stone.