Biomass - a burning issue

[Andy Simmonds]

This is the place to give us your feedback on the Biomass paper

[Kate de S]

You can now see the paper, and the associated press release, at http://www.aecb.net/new_releases/

Please read the paper before posting responses as a number of people have admitted to responding first.

[Guy Crocker]

As with most things the availability of local supply is a major part of the consideration. Traditionally timber has been used as fuel in rural areas where gas is generally not available. A lot of it coming from natural wastage ie. fallen trees/branches, timber not of sufficient quality, and waste. Such timber and its use close to source I would consider perfectly acceptable. However,in all other respects,I would agree wholeheartedly with the authors. I do think that market forces will very soon start to curb the use of biomass for fuel (apart from waste), simply because of cost,and in the long term land will become too valuable a resource for growing food to waste it on growing fuel. If timber is used effectively in construction, and buildings are designed for deconstruction, so that at the end of their useful life they  can easily be broken down into their constituent parts and re-used (min use of adhesives,and screws and bolts instead of nails), then much of the timber can probably have a life measured in centuries,rather than decades, before it eventually becomes fit only for burning.

[fostertom]

Lively discussion kicking off here http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6241&page=1#Item_2

[Andy Simmonds]

"fallen trees/branches, timber not of sufficient quality, and waste."

I understand that timber and even bark can be used in manufacturing wood fibre insulation boards (eg pavatex/therm and the like). Not sure of the exact quality limits for the material.

I love fires - but opted not to rely on a woodstove for our nr. passivhaus refurb in hereford due to the air pollution aspects in town. Wish others would bear this in mind, as all sorts of crap is burnt locally (apart from one sweet soul, who burns properly seasoned fruit wood.mmm)

Got a nice picture (which I will post some time) of me and my wife having an outside evening fire (in Chiminea) just outside the house, with the smoke going up past the MVHR air intake and dirtying the intake filter in the unit (turned th eunit off for the evening because of this, and no the kids didnt suffocate..)

[Andy Simmonds]

This was interesting from Peter in Hungary: taken from the Green Building Forum:

 

Biomass paper quote being responded to in Peter's post: "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.

[Alan Clarke]

Indeed - similar issues of local fuel wood sources disappearing was one of the prompts to write the paper. A year ago a local firewood business here stopped trading - not despite the rise in biofuel use, but because of demand they were no longer able to buy "waste" wood at a price they thought the local market could stand.

Then a timber merchant reported that slabbings - the offcuts when planks are cut from logs, and until recently a very cheap source of firewood - were no longer available. Finally another timber merchant complained that a stand of softwood they had wanted to buy for timber had all gone to be chipped for fuel. Not just the waste and offcuts, but the whole lot.

I think Guy is right to point out that local use of waste timber in wooded rural areas is not the issue we are addressing. Instead it is the massive upscaling, thinking what works on a small scale, perhaps just using dead and damaged wood, or managing a coppiced, makes wood as a fuel per se a low carbon option, rather than the whole management cycle being sustainable and renewable. 

Thinking that biomass is automatically low-carbon, irrespective of where the fuel is coming from, the size of the resource, or the loss of alternative uses for the finite resource, is the problem we are heading for.  Large numbers of schools have been built with biomass boilers in order to access additional funding for a supposed 60% reduction in CO2 emissions (compared with 2002 regs). Any proposed code 6 housing development - supposed to be the building regs standard in 6 years time - comes with a biomass district heating system as standard. And biomass power stations currently on the drawing board for the UK would have an appetite for far more timber than the UK produces in total.

The first conclusions I drew from looking at the finite supply of biomass were that if you use wood as a fuel in a building, and say "it's OK I don't need to insulate it - biomass is zero carbon" you then need to look at what happens if you do insulate, and burn less. In the current market that means there's more biomass for someone else.  So with the finite nature of the resource, if you waste biomass because your building is inefficient there's someone else who will have to burn more fossil fuel as a result.

Looked at this way, biomass clearly isn't a magic wand to make your building low carbon, the question we asked ourselves is "what is the carbon impact of burning biomass then?"

Alan

[Nick Grant]

Just had a PM that I will paste here:


Biomass
« Sent to: Nick Grant on: September 07, 2010, 09:18:54 PM »
« You have forwarded or responded to this message. »
     
Nick

AECB are publishing this statement: 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.

1. Lower building efficiency is not the "cause" of biomass but of poor design and consultancy/lazy clients. Im all for making every building passiv.

2. Biomass burning releases CO2. There are some unavoidable emissions (24g/kWHr DEFRA figures) - from fossil fuels in growing and transport etc (* this study assumes fertiliser is used in growing and it is trucked 50miles - in practice the distances are shorter and we havent used fertiliser on trees in 30 years in the UK) .

The rest of the CO2 would have been released anyway - the trees exist, they are reaching the end of their lives and they fall over and decay. By taking the material offsite we can use them to produce heat locally instead of fossil fuels. Thus biomass boilers are substituting real fossil fuels in the real world. The trees have to be managed sustainably (thus they are replanted and the CO2 is locked up again). To say biomass is more CO2 polluting than coal is blatantly wrong.

If you have a real problem looking at this and want an independent review  speak to David Reay - Edinburgh Uni http://www.geos.ed.ac.uk/homes/dreay

3. Look at it another way - In Scotland we have 10 million tonnes of potential sustainable yield (annual volume that can be taken without affecting overall fibre levels). We only use 8m tonnes per annum. There is 2m tonnes there that could be used for displacing fossil fuels - this material will otherwise sit in the forest and decompose producing CO2 (and probably some methane). No one is going to use construction logs to make woodfuel (price is £45-65 per tonne)- we are talking about the other useful bits that are currently left (£25-35 per tonne).

That 2m tonnes is about 10% of our current heat use in scotland (or in other words the same as 50% of our electricity being renewable).

4. Instead of promoting local energy source AECB are promoting the use of coal instead, beacuse that is how your press release reads?

Dan

[Nick Grant]

Just to be clear, the 'AECB' are saying nothing at this point. The discussion paper was commissioned as research because of various building design related concerns. The discussion paper has been peer reviewed by many experts and is the result of several months work that has changed the author's views, however it remains their views not those of the AECB.

The 'zero carbon fuel' assumption leading to less efficient buildings is as Dan says not inherent but it is a reality in the UK. The original paper had a graph from Bill Bordass taken from the Passivhaus Schools conference but we removed for the sake of brevity as it was not self explanatory. Attached here. Point we were making is that the Passivhaus school had to meet an energy rather than carbon target whilst the UK schools were designed to carbon targets, many winning sustainability awards and claiming to be low carbon. That the Reidburg school uses biomass heat confuses the story so we left it out and I'm wishing I hadn't mentioned it here!

Good to see agreement on potential biomass yield around 10% of heat demand for (Scotland) (although I'd argue this is not the same as 50% of electricity being renewable.)

It would be interesting to see if the anecdotal evidence (people working at our two local saw mills) that good timber is going for chipping is true but that isn't the crux of our argument.

As we say in the introduction, we heat our homes with wood (although our usual supplies have dried up due to demand) and would love to be proved wrong.

I'll be giving a presentation and taking part in discussion (hopefully with Alan) at the AECB conference at CAT, a site that is very much built around a biomass heat (and if they can make it work, electric) strategy. Hoping this can be a constructive discussion rather than a public lynching.

Nick

[Andy Simmonds]

I have been unable at present to login to the Green Building Forum (..now resolved), meanwhile I wanted to say this (in response to a post from Keith Hall, Editor of GBM on that forum):

"the position that the AECB is taking on this matter"(quoted Keith Hall)

This is a great debate going on here [GB forum]. 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, and that is what it is.

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 current thinking, appropriate either in a small scale  or low population context, is adopted without 'upscaling' that thinking by the mainstream to be applied at a much larger scale.

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 different sectors (rural small holding cf urban home etc) or to be used up for power generation, thus limiting availability for more 'worthy' users!.

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, I have resisted so far tubs of ethanol gel that mimics a real fire, and with emissions that the MVHR can deal with! I just know someone will now tell me how bad candles are.

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 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.

BTW again: as far as I can see, Hereford City is not covered by the Clean Air Act? Is your area? I am worried medium to longer term about air quality issues in Hereford as a result of energy costs and the Biomass as fuel issues. If it really helped things I might accept poor air quality...

[Nick Grant]

Clearly lots of possible discussions but as one of the author's I'm keen to focus on the actual discussion paper which is not about a few people in the country with wood stoves Although the same logic also applies to us, if that was all the problem was we would not have felt the need to write this.

[Kate de S]

I think that, as the authors say in their paper, the problem lies with believing the burning of biomass to be "green" when it is, of course, the growing of it.

Going on to sequester the biomass is then clearly a better choice than burning it, when you've only got the one bit of wood. Which in a manner of speaking, we have.

But what happens instead is that people start to assume that if you are burning biomass, it doesn't really matter how much you burn because "its all renewable, isn't it?". This is how some of the incentives are set out at the moment, and also, how some people think. (I have heard this argument used to justify bonfires, by the way - "Its OK to burn this pile of tree prunings because its zero carbon, isn't it, its all renewable"!).

The point I'd like to make is that its also renewable when you DON'T burn it, but in that instance, it is also a lot lower carbon. Negative in fact. So each bit of wood burnt has a "carbon reduction opportunity cost". (Yes OK you'd need to come up with a slicker way to express that.) And burning gas for the same heat, because of the chemistry of methane, actually has a LOWER "carbon reduction opportunity cost".  Better illustrated in the graphic with the log pile in the paper, perhaps!

So: if as I believe, its growing, not burning, wood that is such a good thing, how about lobbying for  incentives (eg tax relief) for carbon-negative materials?

Kate

[Andy Simmonds]

I agree, Nick, however it is also useful - whilst ensuring we regularly return to the specific issues raised in the paper - to acknowledge that there are  also emotional and historical aspects to the use of trees that influence our thinking and provide the context for the more focused debate. Kate - I like what you have written in your post below. Similar conceptual issues arise when trying to talk about the energy NOT consumed as opposed to energy generated 'renewably' - except that that debate is more advanced.

[Andy Hamilton]

Kate, Nick, you seem to assume that the wooded area in the UK is fixed. Hence your choice of burning or growing wood.

With the price of wood going up for use in biomass burners, more woods will be planted (especially in the north in redundant sheep farms). Note that this will sequester CO2 in that a coppice has a high degree of captured Co2 both in growing wood and the carbon rich soil beneath the trees, incorporating decaying leaves and branches.

Andy

[Andy Simmonds]

It's all about a limited resource being 'fought over' by current users whilst wisely anticipating needs of new users in the future.

Andy - have any solid studies been done that suggest a possible maximum area available for reforestation in the UK, in the light that we would probably also need to plan for more land to be cultivated for food, and probably more for stay at home tourism etc? Be good to get an sense of scale on the reforestation possibilities?

It would also be interesting to see what current quantities of waste wood are being used say for the production of wood fibre board insulations abroad, and also re developments of biomass in production of next generation plastics.

i still feel that there is an unanswered case for a massive investment in demand reduction (for buildings, serious energy conservation via extensive fabric measures) before investment in promoting wood as a fuel. If there is serious money available to spend on any (cost effective for uk citizens) carbon reduction measures then (effective) demand reduction + low carbon heat supply via DH should get one of the first calls on it...and this may means more than the £10k / house being discussed at the moment for refurbishment measures.

Another question, Andy - do you support the RHI as proposed by the government? AECB consultation response refers!