By email from Robert Palgrave of Biomass Watch:
good insights, I wanted to post the following on the AECB forum, but don't have access. I hope my thoughts on biomass power generation are of interest.
The question posed here is essentially this: is biomass heating being used as a convenient, indeed lazy way of reducing a building’s operational carbon footprint? I think Nick and Alan have put forward a good case that it is.
But as they hint in the final footnote, - ‘We have focussed on buildings as they are our daily concern, but the most significant emissions will be from biomass fuelled power stations and co-generation in existing ones’ - the problems caused by the belief that biomass can be a large scale climate fix extend beyond its use for heating.
At the heart of the issue is policymakers’ mistaken view that ‘biogenic’ emissions can be assumed to be zero. Essentially the theory is that the biomass carbon you burn will be sequestered from the atmosphere by someone else growing sufficient plant material, at another place and at another time. This is highly dubious carbon accounting.
Where this gets very worrying is in power generation, because of the scale. UK Government sees biomass electricity as a key part of our low carbon transition, encouraging its expansion meanwhile acknowledging that indigenous supplies are inadequate. It openly encourages large scale imports of wood pellets and wood chips as fuel. Since April 2009, the UK has had a financial support scheme for renewable electricity that rewards operators of solid biomass power stations with about £65 per MWh. That’s an uplift of about 150% on top of the wholesale price of electricity.
As a consequence there are now proposals and schemes in the planning system for around 35 medium to large size biomass power stations – not CHP – with a total generating capacity of nearly 5GW, and an annual consumption of around 39 million tonnes of fuel, mostly imported wood chip. The demand swamps the UK's current and potential production of timber. Were all these power stations to come on line, the annual ‘subsidy’ - paid for by all UK electricity consumers to the operators - would be around £2.5bn per year. Over 25 years, we're getting to the level of Trident.
Nearly all the proposals are for locations close to ports or even in ports to facilitate imports. Most of these power stations have very poor overall efficiencies. The guideline figure used by DECC is a mere 25%. The best coal-fired power stations can achieve 45%, Combined Cycle Gas Turbines even higher.
In order to qualify for financial support, biomass power stations have to meet a few tests dealing with ‘Carbon and Sustainability’. On carbon, the intention from 2011 is that they will have to show a carbon saving of at least 60% relative to a benchmark comparator of EU-wide fossil electricity. On the face of it that sounds impressive. However, the benchmark EU carbon intensity is misleadingly high. At 713 kgCO2/MWh, it is 23% higher than the existing carbon intensity of the UK grid. The absolute carbon intensity required of biomass electricity is therefore going to be 285 kgCO2/MWh – this is really only a 50% saving on existing UK grid electricity and far exceeds the suggested target for overall UK grid electricity in 2030 of just 80 kgCO2/MWh.
But the crunch is that the official methodology for calculating carbon intensity for biomass electricity assumes that all smokestack emissions are sequestered and can therefore be written down to zero. If it were so. Even if the required replacement trees were planted and brought to maturity, every year we will be creating a carbon debt by burning more of the standing trees while the new trees grow. As biomass consumption expands year on year, the carbon debt gets bigger and the rate of replanting needs to increase to have any chance of eventually paying it back. Like a loan shark operation.
The biomass carbon debt is explored in detail in a recent paper “The upfront carbon debt of bioenergy” from Joanneum Research, May 2010. Available at www.birdlife.org/eu/pdfs/Bioenergy_Joanneum_Research.pdf
The current UK and EU policy on biomass electricity is damaging our slim chances of reducing current carbon emissions fast enough. Consumers are also being conned into paying more for ‘green electricity’ which in reality is as damaging for the climate as burning coal. At least new coal-fired power stations are likely to be required to have carbon capture systems fitted. And the Committee on Climate Change is now recommending to Govt that new gas-fired power stations should only be built with carbon capture.
Biofuelwatch started out opposing the use of bioliquids on an industrial scale for transport. Those biofuels are now entering the power generation market in addition to solid biomass. At the scale proposed they are very damaging, and like solid biomass for power, are a very worrying false climate change solution.