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This report sets out the results of analysis carried out by AEA for the Environment Agency as part of its work to support the development of a sustainable bioenergy industry in England and Wales.

It assesses the greenhouse gas (GHG) savings that biomass feedstocks which could be used in heat and power schemes in the UK offer compared to fossil fuels. The savings are calculated using the Biomass Environmental Assessment Tool Version 2(BEAT2), which was developed for the Environment Agency and Defra (Department for Environment, Food and Rural Affairs) by AEA and North Energy Associates. BEAT2 calculates the emissions of carbon dioxide, methane and nitrous oxide over the whole lifecycle of a biomass energy scheme (including biofuels), from cultivation of the energy crop, through processing and transport of the fuel, to combustion of the crop at a power station or boiler and disposal of ashes.

This analysis has resulted in the following conclusions, with a separate policy summary
report also available that sets out the Environment Agency’s recommendations based on this report:

Greenhouse gas emissions from energy generated using biomass are generally, but
not always, lower than those from fossil fuels.

For example, using short rotation coppice chips to generate electricity can produce 35 to 85 per cent less emissions than a combined cycle gas turbine power station per unit of energy delivered, whereas using straw can, in some cases, produce over 35 per cent more.

How a fuel is produced has a major impact on emissions.

Transporting fuels over long distances and excessive use of nitrogen fertilisers can reduce the emissions savings made by the same fuel by between 15 and 50 per cent compared to best practice.

The treatment of avoided emissions from the disposal of wastes is critical and needs to be further developed.

We consider that in cases where it is clear that a single route accounts for most of current disposal and is likely to do so into the future, then an allowance could be given for the emissions avoided from disposal. This would be the case, for example, with animal manures where the final point of disposal is almost always spreading to land.  For waste feedstocks such as waste wood, where there are a number of potential alternative uses for the wood, as well as disposal, it will be more appropriate to take an average of emissions savings over these routes, or the disposal route with the lowest GHG saving to ensure that savings are not overestimated.

 

Land use change can negate any emission savings.

Using formerly fallow land to grow bioenergy crops can reduce emission savings from a fuel by up to 10 per cent. Planting on permanent grassland is worse, with emissions savings significantly reduced and in some cases reversed.

Setting minimum standards for GHG savings could help maximise emissions savings from bioenergy production.

We consider that appropriate minimum standards for GHG savings for biomass feedstocks would be as set out below:

 

 

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