Is biomass worse than coal?
Bioenergy policy
The UK Bioenergy Strategy published earlier this year, aims to support sustainable bioenergy in order to reduce emissions. With this goal in mind, the UK plans to continue subsidising the use of wood for large-scale power generation. The strategy makes it clear that the use of wood, in comparison to coal, will result in emission reductions. As a result, several British power companies are actively following this directive.
Dirtier than coal?
A new report challenges the assumption that biomass is carbon neutral. ‘Dirtier than coal?‘, a combined effort between RSPB, Greenpeace and Friends of the Earth, goes so far as to say that replacing coal by burning whole trees would increase emissions by 49% over the next 40 years. The report identifies two key critiques of the assumption that wood is a carbon-neutral energy source.
1. Wood is inefficient
Stuart Housden, Director at RSPB Scotland, explains that the aim of government biomass subsidies is to shift towards lower carbon intensive inputs. Housden argues that replacing coal with wood will not have this outcome.
“When trees are burnt in power stations, CO2 comes out of the chimney, just like it does when you burn coal. The difference is that wood is less energy-dense and is wetter than coal, so it takes a lot more energy to harvest, transport, process and finally burn it…
Transport emissions are likely to rise as the UK will be forced to import wood in order to meet rising demand. On a local scale, as demand and price rises, industries using wood may be pushed into using cheaper options. This ‘product substitution’ could result in the use of higher carbon alternatives.
2. Carbon debt
Advocates of biomass argue that losses in carbon storage from harvesting of wood is compensated by regrowth. This leads to the second ‘accounting error’ of the bioenergy strategy. It fails to recognise the time lag between initialising regrowth and mature, carbon sequestering ecosystems. This issue of ‘carbon debt’ is one of the most serious criticisms of biomass for energy production. Housden goes on to point out that,
“It can take decades, if not centuries for the trees to recapture that carbon, leaving us with more emissions in the atmosphere now – when we least need it”.
Recommendations
There are three main points that can be drawn from this report
- There is the need for an accurate accounting system that is aware of carbon debt and material substitution
- Bioenergy should refocus towards truly sustainable inputs. The report advises further investigation into waste products for energy use, such as wood waste from forestry
- There must be further discussion over biomass as a renewable resource. What can and cannot be classified as carbon neutral must be clarified in a policy context
Coal is not a sustainable option for energy production. The report does not refute this fact. It does however, call into question the assumptions we have regarding biomass. Governments have a moral obligation to examine the nature of biomass before incentivising industry to shift towards it.
About the author
Acacia Smith is a New Zealander now based in London. She holds a bachelor degree and postgraduate diploma from Victoria University of Wellington. She has worked for the Council for International Development (CID) and more recently in Bolivia for CIWY, a network of private parks for the rehabilitation and conservation of Amazonian fauna. Acacia is passionate about sustainability and the role businesses can play in promoting a better, more sustainable future
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