Biomass - a burning issue

[Jane & Peter Harris]

It strikes me that most of the comments are about the cost of timber and its other possible uses  But the main point is that any sort of energy however produced should be used very carefully and not wasted by bad building design. There is nothing better than using no extra energy in building occupation that ought to be the best result

Peter Harris

[Nick Grant]

In response to the comments that good wood would not be chipped I have got permission to paste an email from a friend whose brother works in a local sawmill, not allowed to mention sawmill name unless I ask the boss:

"Hi Nick,

I was alerted to the insanity prevailing in the biomass energy situation a couple of weeks ago when my brother (who works at **** Timber) told me that the company had been informed that if they wanted the timber that had already been ordered they would have to pay an extra 7%.  This was because timber had increased by that amount due to the demand for woodchip driving the price up.

Then I heard that a softwood plantation near Cheltenham that had been scheduled for logging for milling timber had been cut and entirely chipped on site to supply chips to a power station.  **** have now been told that there will be a price incease every month for the next 4 months at least. Kronospan in north Wales have recently outbid the sawmills who source their timber from the Forest of Dean to ensure a supply of chipping timber for their chipboard products, the Welsh forest not being able to cope with demand, much of the timber being chipped on site.  It seems mindless to me that good milling timber should be chipped, let alone chipped for burning.

He then reports some general findings from the internet:

I looked a little further into these biomass fuelled power stations and find that there is one operating in Yorkshire, Sembcorp, opened in 2007 and using 300,000 tonnes of woodchip a year.  Another is at Steven's Croft, near Lockerbie. There may be others, and most (if not all) of the coal burning stations are also using some woodchip.

At least two more dedicated woodchip power stations are under construction with quite a few more in the pipeline.  One under construction is at Anglesea, that is designed to consume 2.4 million tonnes of woodchip per year, and another is at Port Talbot and designed to burn 3 million tonnes per year.  The figures I saw reckon that between these two that is well over 50% of the entire timber output (of any sort) of the UK.  It is planned to import woodchip by sea from anywhere in the world where it can be obtained, but it will have to be baked before shipping to ensure no pathogens are brought into the country with it.  The "Carbon Footprint" of burning this sort of fuel can hardly be considered small to my way of thinking.

Anyway, you probably know far more about the wider use of biomass than me already, but I'm as sure as I can be that the information in the first two paragraphs is accurate.  The information has certainly made me put my plans for a wood gasifying boiler on hold!

John"

This email got forwarded to Anna Jenkins Director of Ethical Change - a small forest and wood product focused consultancy - and the director of FSC UK until August 2005.

She replied:

"Yes I must say that Nick's friend is spot on in his information. I have
heard very similar.

There is very little that can actually be considered 'waste' from a sawmill
or other wood processing plant these days. It will vary from place to place
(depending on their technology, development, local market etc) but really
its what would be genuinely dumped under normal
circumstances: 'waste to landfill'.

So wood chip and saw dust are definitely not waste. They are co- products
and have a definite value and there are increasingly bidding wars over them.
Sometimes their value can outstrip a primary product even. As the demand for
industrial scale woodchip for energy increases then so will the bidding wars
and thus the price. Things cannot be turned round quickly in terms of supply
in this country as we have only so many trees and it takes a long time to
grow more. So supply will increasingly come from offshore like the pellets
you mentioned and the great pile of chip I saw at the port in Riga in Latvia
destined for the UK and Sweden for energy production that I saw a couple of
weeks back when auditing there. Black liquor from the paper industry that
has always been considered waste is now a valuable fuel source in many
developed countries, so that too has moved from 'waste' 
to 'co-product' now.

This biomass question and
specifically biogenic carbon accounting is a very critical issue and perhaps
the folk at AECB would be interested to know how much things are kicking off
in the US on this front. To that end I attach a submission that we just sent
as the Environmental Paper Network to the US Environment Protection Agency
as it succinctly sums up what we're doing and has a useful list of
references and links with it. Not sure it mentions the letter to congress
from 90 scientists calling for proper accounting of biogenic carbon
emissions but can forward separately if need be.

You are very welcome to forward this email and the attachment to Nick or
others if you think it would be helpful. Please warn them I don't have much time to get into the debate
I'm afraid, as much as I enjoy it, as rather snowed under to say the least!

Warm regards

Anna"

[Andy Simmonds]

Check out John Willoughby's fuel price index to see latest relative costs of different fuels.
Useful.

http://www.johnwilloughby.plus.com/dfpg1005.jpg

[Kate de S]

...easier to read at 200% by the way. And of course he gives the SAP figures for CO2 including for wood - which as we have seen above, not everyone agrees with.....

[Alan Clarke]

Here is a reply to an email where I have tried to clarify the thinking behind our statement that biomass is not a low carbon fuel:

We aren't disagreeing that it is possible to have a renewable, sustainable energy system of, say, fuelwood coppice and combustion, and over a reasonably short term this can be carbon neutral.
 
However this doesn't make wood a carbon-neutral fuel - a subtle but important point that we think is leading to serious errors in policy.

To explain why biomass is not necessarily zero-carbon, consider anaerobic digestion - this produces methane from vegetation, and can be similarly considered carbon neutral. So is methane a zero-carbon fuel? Of course not, no one would argue that it is.  If we write a paper saying that methane, CH4, is not automatically a zero- carbon fuel, just because it can be generated in a carbon neutral manner no one is going to argue with us. 

However the situation with wood is similar (though not the same): burning the fuel emits carbon dioxide; it is only the way the fuel is generated that makes the case for carbon neutrality, yet the conclusion generally drawn in the case of wood is that the fuel itself is zero-carbon irrespective of the net carbon balance of growth against combustion.
 
Our point is that it is a mistake to attribute any fuel with intrinsic zero-carbon properties if these rely on a specific management cycle to produce the fuel in a genuinely carbon neutral manner.  The result, we are seeing, is an increase in the burning of the fuel, without a corresponding increase in the removal of carbon from the atmosphere.

Now of course timber isn't a "fossil" fuel, but forests are generally hundreds or thousands of years old, and mining these for fuel is no better in carbon terms than mining coal. However this is the inevitable result of promoting the use of biomass as a fuel, rather than promoting the growth of biomass as a carbon sink.
 
So we get the situation whereby biomass boilers are subsidised, and the RHI promises to pay you to burn wood - the more you burn the more you earn! Yet it is really production of biomass we need, not destruction.

This is why we have separated biomass growth from biomass combustion - to see the issue in a new light. It may seem simplistic, but it is a good way in our view of getting out of arguments over how long you need to wait for timber to regrow, impact on soil carbon, etc etc. 

Optimistically some see burning more wood as some sort of incentive to increase the area of woodland - but history shows the opposite tends to happen. What does increase forest area is deliberate planting of trees, nothing else seems to do it.


Alan

[Christine J Armstrong]

I agree with the general theme that we need to take a critical look at the use of biomass and promote other uses of biomass such as renewable building materials.  I am concerned that the article polarises the discussion and may not be as helpful as it could be.

The paper aims to analyse the biomass material in isolation when it should be viewed within a broader system boundary that includes negative and positive upstream impacts that take into account growing, harvesting, processing and transport.  Sometimes this results in a lower net carbon fuel and other times its results in a higher net carbon fuel, we need to make this clear.

It is correct to say that the CO2 emissions per kWh generated from natural gas production are lower than biomass fuel material such as short rotation coppice.  Natural gas yields approximately 0.23kg CO2 per kWh generated whereas dry short rotation coppice yields approximately 0.36 kg CO2 and 0.43 kg CO2 at 40% mc.  However, this is just one component in the system.  There will be instances where the upstream impacts of biomass generation mean that biomass as a fuel source is the lowest net carbon option.  There will be instances when biomass is not the lowest net carbon option, particularly if the biomass is being heavily processed or there are large transport impacts from gate to site.  Narrowing the argument down to the chemical properties of the fuel itself only serves to polarise the debate and as far as I can determine only really benefits the advocates of fossil fuel consumption.

We don’t live in a world of absolutes so surely there are instances where biomass is best used for fuel and instances where it is best used for durable materials such as renewable building materials.  The key is to be able to understand and demonstrate which is which.

There is an element of carbon sequestration even with short rotation biomass crops when you look at the dynamics and equilibrium of the growing and use cycle.  This system has a short half life but it still has the potential to create a carbon store or a carbon sink if effectively managed.   This is not discussed in the paper.

Utilising the biomass for building materials requires energy for conversion into biomass materials.  The CO2 emissions arising from conversion of biomass into building materials or other uses could, depending on the situation, outweigh any carbon savings from substituting biomass fuel with fossil fuels such as natural gas so this needs to be considered.

The difference in CO2 emissions between fossil fuel and biomass is most significant when you compare natural gas with biomass.  If you compare other fossil fuels, the difference becomes less pronounced.  However, as previously mentioned, comparing fuels based purely on their chemical properties narrows the system boundary so much that it makes any meaningful comparison almost impossible.

It is not a mistaken assumption to say that biomass is low carbon and it is wrong to view the fuel material in isolation.  Most people understand that biomass fuel comprises a system were the fuel is regenerated and the biomass regeneration process balances a proportion of the CO2 emissions from the fuel burning.  However, it is true to say that this is unlikely to result in a ‘zero’ carbon system but it can result in a low carbon system.

It is true to say that burning natural gas releases about half as much CO2 than burning biomass to yield the same heat output and in some situations it could be as high as 4 times depending on the fuel.  However, it is not correct to say that this is in part due to the fact that more energy in natural gas comes from hydrogen rather than carbon.

The heat potential in natural gas comes from the enthalpy of the system which is the energy released breaking bonds (in this case carbon hydrogen bonds) less the energy required to break the bonds.  The enthalpy is in the system not in a particular element such as hydrogen.  It is the carbon-hydrogen bond that stores the energy, not the hydrogen.  The carbon-hydrogen bonds in methane have a higher thermodynamic energy potential than the compounds that make up biomass (e.g. lignin and cellulose).   Wood generates more CO2 than natural gas per unit of energy generated because there is a lower change in enthalpy (energy release) in the system relative to the carbon content of the fuel.  Wood has a lower energy potential relative to the carbon content compared to natural gas.  This has as much to do with carbon as it does to do with hydrogen.

I think we need to move away from polarising the discussion and to accept that there are situations where using biomass as a fuel has a benefit and the use of biomass in materials construction has a benefit.  Both routes have the potential to utilise biomass sustainably and unsustainably.  We should be promoting the sustainable use of biomass regardless of the end use which will enable us to keep the discussion on a more positive footing.

[Cindy Harris]

This is a reply to the paper ‘Biomass – a burning issue’, issued on behalf of AECB and written by Nick Grant and Alan Clarke.

First I should say that I have known Nick Grant – on and off – for many years and have the greatest respect for his intellect and his iconoclastic tendencies!

I think the paper raises some important and serious issues. However, I also think it is fundamentally wrong to be advocating a strategy which relies on burning fossil fuels, and is potentially damaging to one of the new and growing industries which has got to be part of the solution towards a low carbon future.

I start from a basically different standpoint, which can be summarised as:
There may well be problems with fuel supply, and there are certainly problems with the regulatory mechanisms governing new buildings, but these are not problems inherent in biomass technology. Lets work on solving these issues to do with how the technology is rolled out, but lets also work on supporting the industry and the technology so that we can benefit from an energy source which could be and should be renewable AND low carbon.

Specifically,
•   I don’t understand why Nick and Alan choose to draw the CO2 sequestration boundary round the building, and not allow that growing trees will take up any of the carbon released by burning timber. There’s no logical reason to ‘decouple tree burning from tree growing’. The theoretical equation of carbon released and carbon reabsorbed admittedly only works over a long period – but it does work - and all wood will eventually release its carbon, even if its use for construction purposes first.

•   Much of the timber grown in the UK is FSC certified or equivalent, which pretty much guarantees at least 1 for 1 replanting, and Forestry Commission figures bear this out, ie. that stocks are not declining in the UK.* There may not be an infinite resource at the moment but if you discount the use of biomass in power stations, and just look at the heating demand from small woodstoves and district heating systems, then the supply is there and the wood pellet supply in Wales is increasing. [As others have noted, anecdotal evidence can never be conclusive. However – we have recently  taken delivery of a large quantity of slab wood for burning – supply is not running out in our area...]
I think its important to distinguish between biomass heating and biomass power station producing electricity – I wouldn’t defend the latter unless CHP is used.

•   There is an assumption in the paper that all timber is suitable for construction – the argument is: don’t burn it, build with it and lock up the carbon. That’s obviously not the case. The bulk of short life Sitka that is grown in Wales IS only suitable for burning, paper making or chipboard, and the demand from the latter two industries has declined for various reasons. We should be encouraging the forestry industry to replant a variety of different timbers – including those suitable for construction – by providing a variety of markets and end uses.

Finally I think it is regrettable that this ‘discussion paper’ was made the subject of a press release under the AECB name – before any formal discussion had taken place. It has certainly been taken up by the building and architectural press as the views of AECB. And the political implications of this on the likelihood of the Renewable Heat Incentive happening are obvious.

Cindy Harris
September 2010-09-26

*Forestry Facts and Figures 2009
  Forestry Commission

[Alan Clarke]

... Most people understand that biomass fuel comprises a system were the fuel is regenerated and the biomass regeneration process balances a proportion of the CO2 emissions from the fuel burning. 

Mark - this is the "understanding" that we think needs to be examined more closely - although a system where the fuel is continually regenerated can be reasonably taken to be low carbon, it is the whole system that produces this beneficial outcome. Just burning the biomass doesn't do it.  However this "understanding" has led to the net carbon remaining in standing timber (and soil) being completely omitted from the SAP derivations of carbon emissions associated with combustion of biomass fuel. This is already leading to undesirable outcomes - both depletion of the timber resource for construction, and the deliberate construction of significant numbers of poorly insulated buildings on the basis that the proposed heating fuel is very low carbon.

I understand that the whole cycle is more complicated than either completely ignoring the carbon balance of the actual fuel, as SAP does, or ignoring the possibility that a biomass fuel industry could add to carbon sequestration in standing crops, as we have assumed. But just saying it's complicated and it could be good or could be bad doesn't seem to us to be leading to  sensible policy decisions.

For instance, to hypothesize an alternative approach, say a coppice grower were encouraged financially somehow on the basis of his stock of standing biomass, ie we paid people to grow biomass instead of burning it, then the wood products he produced would have a more equitable market as fence posts or fuel. No one would be having money thrown at them to burn it all as fast as possible (as proposed in the RHI), so it would only make sense to burn wood that didn't have much value as timber. Also, as the grower's "standing biomass" subsidy would reduce when some wood was harvested, there would be an incentive to increase the coppice area. No doubt there are some difficulties with this in practice, but the principle we are arguing for is to encourage growing biomass - not burning it.

As for polarising the discussion, we didn't say it was simply a choice of burning biomass or gas - rather that burning either is bad, and we should burn less. We're actually pretty agnostic about fuel choice, that's the point. When designing buildings you can assume that fuels will come and go - and hopefully the one with the lowest environmental impact available at the time will be used.

The polarisation we favour is between wasting energy and not wasting it. Biomass isn't a magic fuel that you can just waste as much as you like because it is fundamentally "a good thing". Sure, there are situations where biomass can be the most sensible fuel, but we are saying that you still need to design your building as if you were burning gas - or coal! That is what would make a sustainable building, which is where I think the AECB should focus.

[Alan Clarke]

Cindy
Thank you for your thoughtful response to our paper.
The logic behind decoupling tree growing and tree burning is partly that failing to do this has led to the large scale use of biomass in power stations already seen as co-firing, with proposals planned for far greater consumption in purpose biult biomass power stations than the entire timber production of the UK. This is seen as good on the basis that trees will grow to absorb the carbon – but that is just wishful thinking, there’s no plan to actually grow enough trees – we’re just going to mine forests overseas.
The other reason for decoupling carbon emitted when timber is burnt and when trees grow, is that they are separate! Timber doesn’t all have to be burnt. When you have some useful timber and are deciding what to do with it you do have a choice – release the carbon straight into the atmosphere, or lock it up in construction, usually for 100-200 years for softwood and longer for hardwood. That’s long enough to make a crucial difference.  And if you need to grow more trees to replace those that were harvested for construction, you absorb just as much carbon as if you had burnt that wood instead. You don’t need to burn wood to for trees to absorb it.
You make some encouraging points about timber availability in your part of Wales, but this doesn’t seem to be the case everywhere. And when you say the resource is not infinite at the moment, are you suggesting that it could be? If so then there are some serious issues to discuss with your assumptions!
I don’t think it’s the case that welsh timber is only fit for burning. I expect you are aware of the Ty Unnos project trialling the use of Welsh Sitka in housebuilding, and woodfibre insulation can be made from this timber – surely win-win, and do you really want to encourage burning wood instead of using it for insulation?

[Christine J Armstrong]

Alan

I am glad you mentioned the issue of waste and  I couldn’t agree more.

I think this discussion is missing a key dimension and that is the issue of food and in particular food waste.  Biomass has three uses, fuel, materials and food and we are only discussing fuel and materials.  Land is limited so we can’t afford to waste any.  I have listed some brief statistics published by DEFRA this summer:

http://www.defra.gov.uk/evidence/statistics/foodfarm/food/familyfood/documents/foodwastepurchases.pdf

‘Fifteen percent of all the food and drink purchases that could have been eaten were wasted in 2008. Different types of food and drink were wasted at different rates:

15% of food and drink wasted,
17% of food wasted,
32% of bread wasted,
24% of potatoes and vegetables wasted,
7% of soft drinks wasted,
6% of alcoholic drinks wasted.’

How much land does this waste?

This is very relevant because every acre of land displaced by food waste is an acre that could be put to more productive and more sustainable end uses such as biomass building materials or fuel.  I wouldn’t include the use virgin biomass in large scale power station projects in this.

I appreciate the paper focused on burning as a means of energy recovery but there are other biomass energy technologies available to use and abuse.  For instance, anaerobic digestion is seen as one solution for dealing with food waste by converting it to energy.  I am not saying that technologies such as AD don’t have their place but why don’t we just generate less food waste in the first place.

[Christine J Armstrong]

Alan

Thanks for the feedback.  I have had a chance to respond to some of the other points in your reply.

‘Just burning the biomass doesn't do it.  However this "understanding" has led to the net carbon remaining in standing timber (and soil) being completely omitted from the SAP derivations of carbon emissions associated with combustion of biomass fuel.’

I accept that there are carbon emissions from standing timber and soil that are not recognised in many calculations and depending on the type of degradation, the impact will not be insignificant.  However, this factor applies equally regardless of the end use of the biomass so it doesn’t favour one end use over the other (unless the harvesting leaves more residues in the forest for one end use versus the other).  I can’t see how the impact of carbon emissions from standing timber or soil can be used to support one use over the other (for instance, the use of biomass for construction over fuel) unless the evidence suggests a significantly higher residue in the forest for one of the end uses.

‘But just saying it's complicated and it could be good or could be bad doesn't seem to us to be leading to sensible policy decisions’.

The fact is that the subject is complicated and it could be good or it could be bad.  Evidence should inform sensible policy decisions and unfortunately this subject is awash with a lot of opinion and limited evidence (I am not suggesting this applies to you there are many valid points in the discussion paper).  If we want to inform sensible policy, we need more evidence and start presenting the facts.

I am involved in the biomass materials business so I strongly advocate the use of biomass in products but at the same time there are situations were biomass for fuel must make sense.

Mark

[David OLIVIER]

If it reduces the likelihood of the RHI ever happening, that seems a very large plus - not a large minus.

The whole UK support for FIT and other schemes like RHI as planned is so inept that the advice to clients could increasingly be to do everything which the government doesn't give them a subsidy for, such as passive solar, better insulation, airtightness, gas CHP, failing that a condensing boiler with foreign controls, etc, etc.  Most of this scores quite to very highly on a scale of £/tonne CO2 avoided, unlike much technology supported under the LCBP which is costly and in the case of badly-designed or -installed heat pumps  clearly makes climate change worse.

Needless to say, lay people can't understand being recommended to do the exact opposite of what government subsidiy programs promote. Consultants resent being under a constant conflict of interest between giving their clients best advice re the design of the building and best advice re. claiming subsidies.

[Alan Clarke]

Mark
maybe I wasn't clear - I didn't mean the impact on carbon emissions from the remaining standing timber and soil after harvesting, which as you say is a complicated issue, but instead simply meant the carbon remaining in standing timber by virtue of it not being harvested.

By this I just meant that if you wanted to account for the carbon emissions of using a timber resource, ie a forest, you need to compare the carbon remaining in the living trees in the forest year on year to see if you are just harvesting the annual growth (as SAP assumes) or you are depleting the resource and mining it for carbon.

So as far as this basic carbon balance goes, the end use does matter, since burning the timber releases the carbon to the atmosphere, whereas using the timber for building effectively increases the carbon storage in the built environment.  And when building there is often a choice to use either masonry or timber, with house builders able to switch according to cost, which will depend (amongst other things) on the overall demand for timber. 

Alan

[Nick Grant]

Called local sawmill at Usk today to try and order some waste slab wood for our heating. We are regular customer for timber as well as slab wood and they will try and help but have 6 month waiting list and are not taking new orders. Said that they face competition for whole trees that are being purchased for burning.

Can anyone who thinks wood is not in short supply arrange delivery at reasonable price to address near Hereford, only need about 3 tonnes and happy to saw it into logs?

Not interested in tiny pickup loads of wet wood for silly money.

Nick

[Keith Hall]

Biomass can be sustainable
Notwithstanding that reducing energy consumption is the most pressing requirement for us all, We (Green Building Press) believe the take-up of biomass heating in the UK and the wider world is, and will continue to be, an essential part of the 'move' towards a more sustainable  and safe world. Biomass is a natural, easy to grow and harvest fuel that, contrary to the authors' claims, need not be at the 'expense' of other uses for wood. In fact, anyone with a reasonable knowledge of wood and forestry - how it is grown, thinned, harvested etc, would not have written much of what they have included in this paper.

Early in the paper, the authors chose to dismiss many of the very important factors that make biomass perhaps the most environmentally friendly and sustainable choice for heating (where heating is required). They chose instead to simplify the matter to just CO₂ calculations. To do this is to over-simplify the complex nature of the earth's ecosystems and processes. And their proposal that people should happily plant trees to just offset gas consumption is naive at best and foolhardy at worst.

Putting aside the discussion regarding whether or not we should still be erecting new buildings that require heating at all, it is clear that we still need heat in some form and will continue to do so for some time, in most new, and certainly almost all, existing building stock. In my opinion, a key fuel for meeting this need 'sustainably' is biomass, for five fundamental reasons:
1. Biomass is a renewable fuel (within human timescales).
2. Biomass can be grown locally, close to the point where it is needed.
3. Biomass is energy secure - no need to rely on supplies from other countries.
4. Biomass requires relatively simple technology and equipment to enable it to be grown, harvested and burnt efficiently.
5. Biomass can provide employment, environmental protection of habitat and improved lumber production, all for use in the UK.

Whereas on the other hand, mined natural gas, the fuel which the report seems to lean towards as they regularly compare it with biomass, is unacceptable for five fundamental reasons:
1. Gas is not a renewable fuel (in human timescales).
2. Gas cannot be sourced locally, or even easily for that matter.
3. Gas is not energy secure and forces us to rely on imports from other countries and can be implicated in recent conflicts with other nations and the oppression of third world countries.
4 Gas requires complex and increasingly sophisticated technology to extract, transport, store and burn efficiently.
5. Gas provides for very little UK employment or for any habitat protection.

Note 1: The carbon released from fossil fuels has been long separated from the global carbon cycle and adds to the total amount of carbon in active circulation between the atmosphere and biosphere. In contrast, the CO₂ released from burning woody biomass was absorbed as part of the “biogenic” carbon cycle where plants absorb CO₂ as they grow (through photosynthesis), and release carbon dioxide as they decay or are burned (see www.safnet.org/documents/biomass_science_letter_SENATE7-20-10.pdf).

Note 2: Biogas from anaerobic digestion could quite safely be excluded in the above statements about gas.

Note 3: A study by Cornell University environmental professor Robert W. Howarth in 2010 (see: http://tiny.cc/tzi0j) finds that once methane leak impacts are included, the life-cycle greenhouse gas (GHG) footprint of shale gas would be worse than those of coal and fuel oil. He highlights. "A complete consideration of all emissions from using natural gas seems likely to make natural gas far less attractive than other fossil fuels in terms of the consequences for global warming."  Methane is by far the major component of natural gas, and it is a powerful greenhouse gas: 25-times more powerful than is CO₂ per molecule in the atmosphere (see: http://tiny.cc/tiv9y)

Wood Biomass and forestry - both help to keep us in harmony with nature (in a UK context)
Contrary to the authors' suggestion that forestry cover is on the decline, the opposite is probably true, certainly in the UK. Since 1965, UK forestry cover has grown by 4.3% and 2.7% since 1980. Biomass is now a valued resource from many sectors. In fact trees, per-se, nowadays have an intrinsically high value in the eye of the general public, partly due to their multiple benefits - including as a fuel. A growth in forest cover has many many benefits which the authors seem to have chosen to overlook.

Extensive research over the years has revealed that woodland ownership in the UK is now much more diverse and there has been a large increase in the planting of native, broadleaved trees on land taken out of farming for a variety of reasons - including for fuel security. For instance, the total area of new planting and restocking in the UK was 21.8 thousand hectares in 2008-09. Although restocking accounted for 73% of this total, broadleaved species accounted for the majority (80%). As for new planting (on land not previously used for forestry), since 2004-05, 45 thousand hectares of the UK was put down to new forestry and again, most was broadleaved trees. This increased interest in woodlands and timber as a fuel is more likely attributable to a growing awareness that all nature is interconnected, and forests, woodland, trees and timber are part of what makes us human beings, rather than just robots (see Forestry Commission website for facts and figures).

Forestry is an old profession, therefore much data is available and history proves that when value for forestry is increased, then there is more interest in managing it carefully. UK woodlands will, we believe, benefit from increased extraction of wood for fuel.  Forestry is as much a skilled art as any other professional trade and until recently, UK woodlands had suffered from desperate undervaluation because little use could be found for thinnings, which is an essential step in the growing of quality lumber for building. For instance, when planting a woodland for commercial timber purposes, one would plant trees at a maximum of 1 metre apart. Then over the following 25-30 years as the saplings grow and compete with each other for light, they force each other to grow straight and true but eventually need thinning out. Thinning out would be carried out at least once when the trunks are about 125 - 200mm diameter as the woodland matures. The best, most straight and clean trees would be left to mature and grow on for high quality timber. The thinnings, especially in broadleaved woodland have little value other than as firewood (for which they are perfectly sized) or perhaps for making charcoal, (they also used to be used for pit props in the early days of coal mining).

In an ever-shrinking world we need to choose what we do with our land wisely. Growing wood for both biomass and lumber is far more cost-effective and likely to succeed than growing trees for just lumber.

Further notes on the collective phrase "biomass"
Of course, not all biomass that is currently burned or planned to be burned will be from forestry sourced wood. Therefore, for a proper analysis to be carried out to conclusion each source fuel would need to be examined in isolation for a number of factors before any findings and/or recommendations can be drawn. Notwithstanding that, it seems to be quite commonly agreed that where and when variable origin/quality biomass feedstock is involved, the combustion plant will need to be ever-more technically advanced in order to keep localised pollution to a minimum. It would seem that when sort of activity is carried out, the plant in question becomes a suspected polluter. Perhaps this is an area where more detailed work is needed.


With grateful thanks to the multiple users on the Green Building Forum and others by e-mail and telephone who took the time to discuss this with me on the Green Building Forum in two notable threads:
'Why biomass is better than gas': http://tiny.cc/flwkl
'Natural gas - is it hydrogen or carbon': http://tiny.cc/8qc93wk54e