Blind carbon burning

Kenneth Richter

24 July 2014

The Department of Energy and Climate Change’s (DECC) new research confirms that burning trees for electricity can be bad news for the climate, but will they amend their energy policy now?

Today, over a year after DECC presented preliminary findings (see our comments then) of its biomass carbon calculator BEAC, and after serious concerns that some people were trying hard to get it buried, the report has finally been published

It’s main conclusions are very much in line with what we, other environment groups as well as leading scientists have been arguing for years: burning trees biomass for electricity can be worse for the climate than burning dirty fossil fuels.
This is particularly true in cases where forests are being cut down specifically to be burned for electricity.  

Out of the 32 scenarios for bioenergy the report investigated six were found to result in GHG emissions worse than coal, nine were found to be dirtier than gas and 17 would breach the carbon emissions limit in DECC’s current sustainability criteria.

For example electricity from pellets produced from additional wood generated by increasing the rate of harvest of naturally regenerated hardwood forest in Southern USA from every 70 years to every 60 years results in net-GHG emissions of 3345 CO2e/MWh. Burning coal results in 1064 kg CO2e/MW.

Does that mean all bioenergy is worse than coal? Of course not. Using forestry residues that would otherwise be burned on the road side can lead to real emission savings.

The question is how much of what is currently being burned in huge biomass power stations are such residues.  (Drax estimates it alone will burn more wood per year than the entire UK produces in a year).

Drax say: “Definitely some of our supply chain includes waste residues.”
Which doesn’t sound very reassuring.

In fact evidence from the US suggests that Drax’s supplier ENVIVA is turning whole trees from SE US forests into wood pellets.  

And many UK power stations cannot burn residues for technical reasons as DECC's report points out: "...Furthermore, forest residues often have high contents of bark and non-combustible elements, such as alkali metals, which can cause problems of slagging, fouling and corrosion in boilers, therefore some electricity stations require pellets produced from biomass with low bark contents, such as roundwood."

ENVIVA (Drax's US pellet supplier) logging site
ENVIVA (Drax's US pellet supplier) logging site. Clear cutting or "residues"? by ©Dogwood Alliance

The critical point is that DECC currently has no way to distinguish between biomass that might result in actual carbon savings (such as residues) and the burning of trees which ends up being worse for the climate than burning coal. The Government’s current biomass carbon calculator accounts only for emissions from harvesting, transport, and processing of biomass while assuming that the burning of forest biomass itself is carbon-neutral. 

The report conceded that there are “bioenergy scenarios that could lead to high GHG intensities (e.g. greater than electricity from coal, when analysed over 40 or 100 years) but would be found to have GHG intensities less than 200 kg CO2e/MWh by the Renewable Energy Directive LCA methodology.“

Today's report has shown that this methodology is fundamentally flawed and that the impacts on forest carbon have to be accounted for. Otherwise you are burning blind.

Currently both biomass that is dirtier than coal and good biomass is subsidised with tax payers' money as if they were equal.

So what is needed?

We need proper mandatory carbon accounting that is based on the methodology of the new BEAC biomass calculator. As the Government’s bioenergy strategy was based on fundamentally flawed assumptions about the carbon benefits of biomass it needs to be urgently reviewed. Government plans for biomass burning need to be limited to sustainable resources that are available in the UK, without cutting down overseas forests to feed our power stations. Ministers must ensure that cutting emissions is at the heart of all our energy policies.

For more info on biomass please read our briefing "Felled for Fuel"?

Subscribe to this blog by email using Google's subscription service