How a Gloucestershire church became the first zero carbon church in the UK when it got a biomass boiler and solar photovoltaic array on its roof.
St Michael and All Angels’ Church, Withington in Gloucestershire had a 38kW biomass boiler and 3.23kWp solar photovoltaic (PV) array installed on a hidden roof behind a parapet in 2010.
A number of energy efficiency measures were completed to first reduce heating and electricity consumption. The operating times of external floodlights were reduced (following consultation with the local community) and the existing internal lighting was replaced with efficient compact fluorescent bulbs. This halved electricity consumption.
A 45% reduction in heat demand was estimated based on installing a new efficient pellet boiler to replace the existing old oil boiler which was being fired up every day to maintain reliability.
A manually-loaded wood pellet boiler was selected based on the low weekly heat demand (7 hours per week). Pellets are supplied in 10kg bags. The fuel hopper holds 500 kg equivalent to eight weeks worth of heat.
Installing the biomass boiler proved challenging due to the large size and weight of the pellet boiler and the narrow stairs into the existing plant room. This influenced the choice of boiler, a Froling P4 pellet boiler, which could be dismantled to enable access to the boiler room.
The biomass installation cost £23,110. The project was funded through a combination of national and regional funds, and private donations.
The installation is estimated to save the church £1,100 per year in fuel costs and over 12 tonnes of carbon emissions. The PV was funded from the churches own funds and local sources so the Feed in Tariff incentive of around £1,000 per year could be gained.
This project is a good example of how renewable energy technologies can be used in combination to supply low carbon heating and electricity to a Grade I listed building. The project was managed by a church member who had relevant skills due to his job as a sustainability consultant.