There continues to be a rapid growth in the use of biomass appliances in new developments, driven by climate change and sustainability factors. 

However, concerns over cumulative air quality impacts at a local level have led to a number of biomass schemes being shelved.  Assessment of local air quality at an early stage of planning can identify likely detrimental effects, allowing the proposal of mitigation measures that may allow the development to go ahead.

What is biomass?

Biomass is the term used to describe biological material used to provide renewable energy. Although there are a number of technologies for obtaining energy from biomass, such as gasification, fermentation or pyrolysis, most planning applications tend to be for conventional direct combustion of wood fuel in boilers.  The main non-industrial applications of biomass combustion are:

• Boilers fuelled by wood chips or pellets supplying hot water to commercial offices or public sector premises such as schools, leisure centres and council offices;
• District heating schemes connecting multiple buildings in high density urban areas to a central biomass boiler; and
• Combined heat and power (CHP), usually combining a biomass steam boiler with a steam turbine to generate electricity, most commonly reserved for buildings with high electrical demand or district heating schemes.

The rapid growth in biomass in new developments

There is continuing growth in the use of biomass energy, which is supported by government policy and a number of initiatives, such as The UK Biomass Strategy. The overarching drivers for this growth are climate change and sustainability, with biomass seen as a key renewable energy technology that will make a significant contribution to reducing greenhouse gas emissions and achieving EU renewable energy usage targets.

Other drivers include the Code on Sustainable Homes, making all homes zero carbon by 2016, the new requirement to install biomass boilers wherever appropriate in new school buildings and refurbishments, and local policies to promote and encourage the development of renewable energy resources through the planning system. For London, the uptake of biomass heat and power is further encouraged by the Mayor’s Energy Strategy and The London Plan.

Concerns about air quality

Although the climate change benefits of biomass are well recognised, there are concerns that a significant displacement of natural gas-fired appliances by wood-fuelled biomass units could have a detrimental effect on local air quality, particularly in locations where air quality is already poor such as declared Air Quality Management Areas (AQMAs). 

As well as the potential local impact of emissions from individual biomass boilers, there is concern that the cumulative effects of widespread biomass uptake could lead to localised hotspots and exceedences of Air Quality Strategy (AQS) objectives for particulates or nitrogen dioxide.  Local authorities have a duty to manage local air quality; the local planning authority will want to know the potential impact on local air quality of proposed developments involving biomass, in particular whether pollutant concentrations will exceed the AQS objectives or will compromise the effectiveness of measures set out in Air Quality Action Plans to improve areas of poor air quality. 

Finally, the Clean Air Act 1993 requires operators of biomass boilers burning solid fuel at a rate greater than 45.4 kg/hr (and not otherwise permitted under the PPC regime) to seek approval from the local authority for the chimney height and the dust arrestment plant to be used.

Air Quality Assessments for biomass planning applications

RPS is able to provide planners with a fast, streamlined assessment of air quality impact for developments using biomass energy: 

• Assessment will clearly demonstrate the significance on local air quality of the proposed scheme. 
• Where it is deemed necessary, RPS will suggest mitigation and control measures that may allow the development to go ahead. 
• Chimney height determinations can be performed as stand-alone studies or as part of the integrated assessment.
• For those cases where the detailed rates of emissions from the biomass units are not yet available, RPS can estimate releases from the thermal capacity of the appliance, speeding the application.

RPS is also able to provide planners and developers with a Climate Change Assessment, increasingly required to accompany planning applications: this assesses the net reductions in carbon emissions from the biomass installation and the climate effects of changes in traffic flows, as well as considering the BREEAM assessment, energy statement and sustainability assessment.

Contact:
Jon Pullen, Technical Director, Brighton – P & D
T: +44 (0)1273 546800