Different forms of bioenergy (solid biomass, liquid biofuels and biogas) can provide renewable alternatives to electrification. Each is likely to be suitable in different situations and over different time periods.
Biomass (usually wood) can be used as a direct replacement to existing systems, a new boiler is required but as these are high temperature heat systems (like oil and gas) there is less likely to be a requirement to change the internal pipe and radiator systems and so there is less disruption. Biomass is available in the form of pellets, wood chip or logs. Pellet systems can be more automated and so require less user involvement, while log boilers require filling and more frequent ash disposal but are cheaper to run. For all biomass it is important that dry wood or pellets are used to allow the boiler to operate efficiently and to reduce particulate emissions. Given that biomass can be a direct replacement for heating systems already in use in rural areas (biomass boilers for oil boilers and solid biomass for coal or peat), it is important that biomass options are explored as part of any domestic renewable heat strategy and supported in the transition to low carbon heat in rural homes.
None of the options for moving to renewable heat are easy, biomass boilers are more expensive to install than oil boilers, and they require more on-going maintenance by user (e.g. ash disposal) and servicer. Concerns about the availability of consistent feedstock can affect consumer confidence and there may be worries about the potential for fluctuation in fuel costs. As part of any strategy to decarbonise heat with biomass the issue of emissions and clean air must be considered, with enforcement of stove and boiler standards and quality standards (such as the Wood Fuel Quality Assurance (WFQA) scheme) to ensure the traceability and quality of the fuel used.
However, a clear strategy to develop local bioenergy supply chains in rural areas, education of those supplying fuel, installing and servicing boilers and using them should mean that biomass is an important option for renewable heat in rural areas and one which will bring significant employment while keeping the money households spend on heat in the local economy.
In addition to the replacement of oil central heating with biomass heating, biomass can substitute for solid fuel in systems already in use (18 % of heating in the Western Region is from peat and coal). In general wood is the most likely replacement fuel in stoves and ranges but novel low carbon bioenergy solid fuel substitutes are being developed in Ireland. Read more about the fuels and how they are produced here and here.
In the last decade there has been an increase in the use of wood burning stoves instead of open fires. These are generally secondary heating sources but where wood or other solid biofuel is used instead of fossil fuel they lower the carbon intensity of heating. This is particularly the case if they are used to heat a single room rather than putting on the central heating throughout the house. This is a common practice in larger or less energy efficient homes where the cost of heating can be substantial.
There may be liquid biofuel options too. There has been a reduction in carbon emissions from transport with the Biofuels Obligation Scheme, where a portion of the fossil fuel in petrol and diesel is replaced with a biofuels (read more here). There may be an option to do similar in home heating oil (kerosene) as a short term measure to reduce the carbon intensity of home heating. A recent government consultation on biofuels discussed this possibility and sought feedback on how it might work, based on the level of use and availability of suitable biofuels. The consultation document and the responses are available here.
BioLPG is a potential option, providing an easy switch for those already using LPG as a home heating fuel (0.8% of homes with central heating in the Western Region). It has been developed substitute for fossil fuel LPG (read more here). There is however, limited domestic production and there may be difficulties in sourcing materials to significantly expand production of BioLPG. Additionally, there may be greater demand for use in transport where alternatives to liquid fossil fuels are more limited.
As most of the rural Western Region is not on the natural gas network, there are probably fewer opportunities for using biogas as a direct home heating fuel substitute than in areas on the natural gas network (biogas can be mixed with natural gas and in the longer term could potentially replace fossil fuel natural gas). Biogas is produced in a number of ways but Anaerobic Digestion (AD) of feedstocks such as food waste, slurry, sewage, or grass is the most important option. The production of biogas will take place in rural areas, and depending on the site of the AD plants, there are possibilities for small scale heat networks to use it. However, this is only likely to be possible in the longer term and will be dependent on a complex range of factors.
There are clearly bioenergy options which may form part of the transition to low carbon rural home heating alongside electrification. All biofuels need a sustainable long-term, domestic supply, and well developed supply chains and to be compatible with air quality standards and be sourced sustainably. Nonetheless bioenergy needs to form part of the suite of options for the low carbon transition and we need a clear policy statement on role of bioenergy in decarbonising domestic heat.