Pollution emissions from biomass boilers of less than 20 Megawatts thermal input are regulated under the Clean Air Act 1993, unless they are burning waste material at greater than 400 kW thermal input, or covered by a permit required under the waste incineration directive (2000/76/EC) depending on the nature of the biomass being burnt.
The existing controls for the remaining appliances arise from the Clean Air Act. Local authorities have the power to approve the grit and dust arrestment equipment fitted to appliances over a certain size as set out in regulation. Within smoke control areas designated by local authorities, only boilers exempt by Parliament can be installed.
In February, the Government launched a consultation1 on the Renewable Heat Incentive (RHI) which proposes measures to encourage the uptake of renewable energy including biomass combustion.
Measures are included in the RHI requiring biomass boilers, including boilers less than 20 Megawatt, to meet high standards of emission performance for particles and nitrogen oxides (NOx), though not for nitrous oxide (N2O). The effect of these measures will be to reduce the emission of particles from biomass boilers by at least 60 per cent. for the same quantity of heat delivered, compared to the typical performance of current wood fuelled boilers.