Plans to massively expand wood burning lead to concerns about sustainability
Will the government’s drive for renewable power result in a vast increase in the country’s demand for wood – and if it does, what will that mean for plans to reduce greenhouse gas emissions?
Last week an unlikely alliance formed of green NGOs and the paper, timber and furniture industries came together to warn against the government’s ” reckless” plans to generate more energy from burning wood. The group says that by 2017 the country could be burning thirty million tonnes of biomass, most of which will be wood. That’s about six times the entire UK wood harvest in 2011.
This is disputed by DECC and the biomass industry, who say the figure is lower – but in a way, the exact amount doesn’t matter, because the UK is likely to be burning a lot more wood for power in the near future.
Big plans
Government proposals to generate more power from bioenergy – burning plants, trees and crops – aren’t as well known as its plans for other renewables like wind power.
But in terms of the amount of energy produced, bioenergy could soon be the most significant source of renewable fuel. The government aims to increase the amount of energy the country gets from renewables to 15 per cent by 2020. And about two thirds of that is slated to come from bioenergy.
Burning how much wood?
How much wood and agricultural products will this require? Green NGOs say the answer is ‘a lot’. They predict that by 2017 the country will be burning 30 million tonnes of biomass – equivalent to about six times the UK’s 2011 wood harvest. While not all of this will come from wood, they say most of it will.
The RSPB told us the estimate is based on a DECC review of its main subsidy for renewable power, the Renewables Obligation.
A table in the review appears to indicate that the country could be generating 5,038 megawatts (MW) of energy from biomass by 2017.
A separate government report released in 2010 suggests it takes 6,000 oven dried tonnes (odt) of wood to produce one megawatt (MW) of energy. So if all of this were to come from wood – (the green groups are clear that it won’t) – by multiplying these together the UK would be burning 30.2 million tonnes of dried wood by 2017.
Image - Screen Shot 2013-05-03 At 14.32.03 (note) Source: Renewables Obligation Impact Assessment, DECC 2012. The sum is reached by totalling total deployment in 2012/13 and new build, for biomass conversion and co-firing, dedicated biomass >50MW and dedicated biomass <50MW.
DECC’s figures don’t agree
But DECC disagrees, and the same RO review document that supplies the estimate for 2017 biomass energy production used by the NGOs suggests a lower prediction for the amount of wood the sector will be burning by 2017 – just 17 million tonnes of ‘woody biomass’.
How is this calculated? DECC estimates that there will be 17-28 million oven dried tonnes of wood available for use as bioenergy by 2017, with 9-11 of that coming from UK forests:
Image - Screen Shot 2013-05-07 At 10.47.12 (note)
The document isn’t totally clear, but DECC appears to have taken the lower end of the 17 – 28 prediction, forecasting that by 2017, two million oven dried tonnes of woody biomass will be used used as a source of heat and 15 million tonnes to make electricity.
So why do the estimates differ?
Unfortunately here there isn’t really a simple answer.
The government expects to get some bioenergy from waste products, crops, or vegetable oils as well, so wood won’t account for all of it. The higher figure offered by the green groups refers to all biomass – not just wood.
In the Guardian on Friday, RSPB’s Harry Huyton argues that ” most” of the bioenergy will come from wood. RSPB calculates that based on Ofgem’s figures 76 per cent of biomass burnt in 2011/12 was wood. So differing estimates of how much bioenergy will be produced by burning wood might make up some of the difference, but probably not the difference between 17 million and 30.2 million tonnes.
DECC has applied a constraint to its numbers based on the amount of wood that might be available – although it’s not really clear to us what this constraint is based on.
To further add to the confusion, the biomass industry gave us different figures again. Industry group Back Biomass, which is run by the Renewable Energy Association, told us it expects Drax power station to burn seven million tonnes of biomass and Eggborough around eight million, accounting for 15 million tonnes in total. It says that it expects the total figure for the UK to reach about 25 million tonnes.
But it doesn’t say by when, or how much of this expected to come from wood.
Burning trees and greenhouse gas emissions
Such confusions aside, if all goes according to plan, the UK could be burning somewhere between 15 million and 25 million tonnes of wood for energy in 2017.
Irrespective of the exact figure, this would be a lot – somewhere between two and a half to five times the UK’s 2011 wood harvest.
What effect will this have on greenhouse gas emissions? There had been an assumption that biomass was low carbon, but it comes down to what is being burnt.
Burning whole trees produces more greenhouse gas emissions than burning waste products from the forestry process. One academic for example argues that burning whole trees releases more greenhouse gas emissions than coal over a twenty year period. A review carried out for the European Commission agrees that emissions can be higher than for fossil fuels.
And so attention is turning to where this biomass will come from. The bioenergy industry argues that it will be able to rely on waste products from the forestry industry. Green groups dispute this – they say there won’t be enough wood from these sources, and biomass power stations will end up burning whole trees instead.
In turn, the bioenergy industry says that the UK doesn’t have to get all of this wood from its own forests, as the vast majority of it will be imported. It says that there is plenty of wood in North America – which harvests 500 million tonnes of wood a year already. According to the industry group Back Biomass, 120 million tonnes of wood could be “sustainably” harvested in just three regions in North America.
This has led to a big argument
These competing views have created something of a perfect storm for aficionados of nerdy and heated arguments.
First green groups recommended that the government “limit” subsidies for bioenergy to prevent damage to the environment and the economy. Then the Renewable Energy Association accused green groups of “scaremongering” and spreading “misinformation”.
To be honest, at the moment there doesn’t seem to be a great deal of clarity over the emissions associated with future scenarios of bioenergy in the UK. And what kind of biomass is going to get burnt is at the heart of the issue.
DECC is working on a calculator that will compare emissions from different forest products. It’s not released yet, but an early draft appears to agree with the green group’s position that burning whole trees will be counterproductive.
In summary, irrespective of exactly how much biomass the UK burns in the near future, there’s a serious expansion of bioenergy planned. This could be good news for carbon emissions, but not if demand for fuel means the industry ends up burning whole trees.
All of this translates into a more general question about the viability of the bioenergy industry and where exactly all this wood is going to come from. And it appears that this question is yet to be fully thought through.
In summary, irrespective of exactly how much biomass the UK burns in the near future, there’s a serious expansion of bioenergy planned. This could be good news for carbon emissions, but not if demand for fuel means the industry ends up burning whole trees.
All of this translates into a more general question about the viability of the bioenergy industry and where exactly all this wood is going to come from. And it appears that this question is yet to be fully thought through.