Thought this would be of interest . From the AECB web site

Discussion paper
http://www.aecb.net/new_releases/detail/?nId=9

press release below here
http://www.aecb.net/new_releases/detail/?nId=10

"Biomass – not a green fuel after all?

Defining biomass as a low-carbon fuel is not only mistaken, it is also the cause of higher carbon dioxide emissions and lower building efficiency, according to a paper published today.

The discussion paper, commissioned by AECB, argues that it is fundamentally wrong to define biomass burning as low-carbon, when burning biomass leads to similar carbon dioxide emissions per unit of heat as burning coal.

As the UK prepares to scale up initiatives encouraging more and more biomass to be used as fuel, the AECB decided that it needed to think more rigorously about the issues arising. While it is true that trees do take up carbon dioxide when they grow, this does not mean that the best use for biomass is to burn it.

Instead, the paper argues, the timber can be left unburnt, and put to other uses - for example, as structural timber or other wood products like insulation. Meanwhile we could use other heat sources, that emit a good deal less carbon dioxide than the trees have absorbed, to provide for the same heat requirements.

There is certainly not enough biomass available to both usefully sequester and burn. The paper does not argue that we can sequester our way out of climate change by planting trees and stimulating wood product industries alone. However it clearly makes the case that burning wood is one of the least sensible things to do.

The paper, commissioned by AECB from Nick Grant and Alan Clarke, both experienced building energy consultants, shows how the low-carbon definition for biomass burning is used as a "get out of jail free" card in project design – a biomass boiler then becomes a substitute for good design and energy efficiency. By specifying a biomass boiler, design teams feel they have met their carbon targets, and investing time and budget into efficient, truly low-energy design and construction seems superfluous.

According to the authors, the consequences of current mainstream thinking on biomass as a fuel leads to a ‘lose-lose-lose’ situation:

· Once when the biomass is burnt, releasing twice as much carbon as burning gas for the same heat output

· Again when the building leaks energy, because insufficient attention was paid to energy efficient building fabric and plant design – i.e., the biomass boiler "did it all".

· And further, there is a risk that the timber price is pushed so high by the competition from a growing number of biomass burners, that concrete, bricks and steel have to be created, at very high energy and carbon costs, to make building components that could otherwise have been made from wood.

Explaining why he had written the paper, co-author Nick Grant commented: 'There is a lot of confusion around, with people mixing up the terms renewable, sustainable and low carbon. We need to take a step back from the seemingly endless arguments about the definition of zero carbon, and ask ourselves – what are we really trying to do here? I believe when you do this, it is clear that we need to go back to the simple principle of using less energy, in whatever form.'

The paper "Biomass: a burning issue" is available as a pdf download from the new releases area of the AECB website; go to http://www.aecb.net/new_releases/

In order to gain valuable feedback from AECB members on the issues discussed in this paper, and to invite questions and challenges to the thinking, the AECB has set up a thread on its online discussion forum. Non members can watch the debate – members can post.

Please go to http://www.aecb.net/forum/index.php?topic=2649.0
"

Posted By: jamesingram
Meanwhile we could use other heat sources, that emit a good deal less carbon dioxide than the trees have absorbed, to provide for the same heat requirements.

Thats the problem - what "other sources" . Fossils fuels will expire . Managed forests may not . ( Yes I do concede MAY not )

Posted By: jamesingramThere is certainly not enough biomass available to both usefully sequester and burn.

But could there be ? Irelands' land mass is approx 10% forested . With a population (ROI) of 4.5 million agricultural capacity here can feed 10 times that number so there is scope to displace activity here .

Posted By: jamesingram – a biomass boiler then becomes a substitute for good design and energy efficiency. By specifying a biomass boiler, design teams feel they have met their carbon targets, and investing time and budget into efficient, truly low-energy design and construction seems superfluous.

Which is precisely why b regs set Energy AND C02 targets

Posted By: jamesingram
· Once when the biomass is burnt, releasing twice as much carbon as burning gas for the same heat output

But new timber can be grown .... new gas ?

Posted By: jamesingram Again when the building leaks energy, because insufficient attention was paid to energy efficient building fabric and plant design – i.e., the biomass boiler "did it all".

Not possible to do so and comply with b regs

Posted By: jamesingram And further, there is a risk that the timber price is pushed so high by the competition from a growing number of biomass burners,

..... this flouts simple economic reality

Posted By: jamesingram I believe when you do this, it is clear that we need to go back to the simple principle of using less energy, in whatever form.'

Unarguable . But what fuel will we use in 50 years time ?

James I'm not gifted with the answers to the issue of fuel security . But I can't swallow the thrust of this .

Posted By: jamesingram
And further, there is a risk that the timber price is pushed so high by the competition from a growing number of biomass burners,

We have already seen this happening here and now. A power station in the area us was converted from coal to wood burning as a short term measure waiting for a new brown coal high efficiency power station currently being built on the other side of the country. Needless to say that the wood conversion was done with an EU grant but the result of this conversion is that fire wood prices have gone up to the point that many who used to heat with wood now heat with gas as the difference is not worth the trouble. Apart from making fire wood expensive (here the poorer end of society always heat with wood, and usually with old inefficient stoves) the distances the vast quantities of wood have to be trucked is appalling. By the way the green wood is used at the area power station but any seasoned dry wood is usually trucked to Austria as they pay a premium for seasoned wood that more than covers the cost of extra transport. These events must also raise the question about the use of bio mass power stations without fully understanding / evaluating (or choosing to ignore)the real impacts of this high volume use.

"Agree - but what other criteria do you personally have in mind?"

Sustainable living? A holistic approach that seeks to live more in harmony with the Earth rather than living for short term gain. Where issues such as global warming are an important subset of a global "Sustainable" agenda rather than being the predominant focus.

Posted By: SteamyTeacan you ... define (these terms) so there is no possibility of ambiguity. I suspect not

That's either a strange and despairing belief, or else it's setting the bar too high, to make a point.

'Quantify' is unguided (but dangerously seductive) unless preceded by 'Qualify' i.e. as bot is doing, describing the qualities of what is aspired to. That qualification can proceed a very long way, into deep qualitative understanding, including scientific understanding - and the quantification can begin in support of that.

bot described, as precisely as you can in half a sentence, what 'holistic' means (to him) -

Posted By: bot de pailleto live more in harmony with the Earth rather than living for short term gain

That's a very good start, and there's much more that can be (already has been) said to expand that. Likewise 'Sustainable'.

ST, I'm wondering just what your gut-reaction is about, to what bot said?

Steamy Tea:
Holistic, Harmony, Sustainable: I know, I guess instinctively, what Bot means and I suspect most thinking people do too, given the time to think. If you have difficulty with that then maybe it's the mathematician in you, and maybe that's why everything shouldn't be reduced to a set of figures alone. It's too blunt a tool and too open to abuse, lots of examples there.

But neither is it reasonable to expect to get away with being wishy-washy and saying that "numbers are too hard" and then complain when things don't work. Numbers and engineering in particular are vital to the efficiency that we're going to need to sustain a significant population at anything like current levels of comfort, never mind providing a similar level to those who don't currently have it. You can't make a R744 CoP 5 heat-pump without cracking open a few formulae.

Rgds

Damon

Geographical location has the second largest part to play. Not much biomass growing at the poles, or the ocean surfaces (I tried burning kelp once). Reduction of energy use has the largest.

Think of biomass as solar energy - during Summer the tree grows with the sun's energy and in Winter (several Winters hence, obviously) you coppice it for fuel. And the cycle continues.

Agree that wood for building does sequester the carbon and is therefore ideal, better than use in heating. Best is insulating the socks off our houses, heading towards the Passihaus ideal.

However agree with the ACEB post commentor that wood fuel is a good home for "waste" wood - wood that is produced in areas relatively remote from timber processing plants, and including windfall from trees. There could be a significant carbon cost in getting such wood to a wood processor.

This discussion will run and run

And I have a tale of hope http://constructireland.ie/Articles/Obstacles-to-Sustainable-Building/-From-Recession-To-Renewables/Page-2.html

"Together, the two plants have made Güssing more than self-sufficient for electricity and heat. Vadacz estimates that €18 million stays in the district each year that would otherwise have leaked out. This represents a massive return on the EU and Austrian grants. Moreover, because of the availability of cheap heat, over 1,000 jobs have been created in and around the town"

Posted By: domhoughBest is insulating the socks off our houses, heading towards the Passihaus ideal

There's more beyond Passivhaus - PH is extreme heat-demand reduction plus conservation of internal gains plus a little bit of solar gain but not too much otherwise overheating results. That still requires a back-up heat source and a heat-distribution system of some sort, which may be called upon substantially if the occupants aren't themselves PH enthusiasts and do things like leaving windows open.

Beyond PH is not-quite-so extreme heat-demand reduction (incl not-quite-so fanatical airtightness) plus conservation of internal heat gains plus maximised heating-season solar gain/capture and its active transport into longer-term useful storage than PH can provide. That can provide a small surplus of stored heat that can bridge over most heating-season sunless spells, resulting in minimal call, if any, on a supplementary heating system, even when the occupants misbehave a bit!

Sinnerboy, the efficiency of a given biomass boiler should not be just compared against the efficiency of a given gas, oil or electric one - otherwise an electric boiler (100%) would be considered green by that reckoning (which it surely isn't given the UK's current method of generating electricity).

Apparently electric heating actually emits 2.27 as much CO2 per kWh of heat as gas heating although the Building Regulations ADL1-2006’s “fuel factor” of 1.45 for electricity only accounts for part of the extra CO2 emissions for example.

The emissions in kg CO2 per kWh as well as the unit cost p/kWh have an effect on emissions and SAP Ratings

Table 12 of SAP 2009 details the various fuels and comparative emissions for those interested
http://www.bre.co.uk/sap2009/page.jsp?id=1642

Posted By: SigaldrySinnerboy, the efficiency of a given biomass boiler should not be just compared against the efficiency of a given gas, oil or electric one -

It is - and should be - in the first instance in DEAP / SAP

Posted By: SigaldryThe emissions in kg CO2 per kWh as well as the unit cost p/kWh have an effect on emissions and SAP Ratings

Exactly - these factors are then added to calculated demand energy to then calculate primary energy (and CO2 emissions) in DEAP / SAP .

Electrical use is heavily penalised . Many owners of relatively new and relatively well ( sort of ) insulated Irish apartments with Elec storage heating are discovering this the hard way with BER ( EPC ) D rated dwellings .

Since it's possible to fit a wood boiler that is clean enough for a smoke control area, the environmental health issues seem to me to be extrinsic. Having looked at the paper, it seems short on quantifiables - and long on speculation. In particular, no real evidence is offered for the claim that biomass boilers operates as a disincentive to energy-saving measures - and certainly there is no attempt to compare the disincentive created by biomass boilers with that created by other heating technologies given a similar 'green' tag (e.g. heat pumps, UFH). If you are storing your own wood from one season to the next, splitting and stacking it, and having to bring it in to burn - I would expect that operates somewhat as an incentive to minimise your use of fuel. Maybe this is also what bot was getting at with living in harmony with the earth - use of kWh is very abstract, running down your stored wood is very concrete. Automated pellet boilers in an outbuilding are a different thing - moving energy use a bit more towards the abstract again.

The CEO Andy Simmonds requested the posting of this comment. (He is unable to access at present for some reason)


This is a great debate going on here. I am not going to say much at this point except to emphasise that this is NOT a 'position' that the AECB has 'taken'. It clearly states on the paper that this is a 'discussion' paper.

As others have said it is a debate that has become important to stimulate, because of recent moves to increase dramatically the amount of biomass being used as fuel. This means that different issues (issues of scale) arise that were not important when only a small amount of wood was being used as fuel. As said elsewhere, it arises when thinking appropriate either in a small scale or low population context is adopted by the mainstream.

We all love fire - in my personal view fire is a powerful and ancient energy that should be part of of our everyday lives, but not to be relied on to heat large numbers of our houses across diffrent sectors (rural small holding cf urban home etc). Places for open / log fires: pubs, community buildings, festivals, hospitals (!!), barbecues, campfires etc. And I won't argue with a few homes using local waste wood either as long as they are not in my town and burning treated, painted, melamine faced offcuts and other crap (as is often the case....) !

At our nr. passivhaus refurb in Hereford, we occasionally light a fire in the Chiminea and sit outside for the evening. This winter (having taken out the radiator in the living room) we will use candles in the old fireplace to satisfy our primeval needs (and add some aditional warmth to the room. MVHR keeps the air clean, I will see how dirty the filter gets !) etc etc. BTW gas and electric consumption on the house are available here for those interested to see how it is working. http://www.retrofitforthefuture.org/search.php?s=enerphit

I just know someone will now tell me how bad candles are.

i look forward to the debate starting to settle down and start to provide some indication as to nationally how we should use this complicated resource wisely.