The majority of domestic renewable heat incentive (d-RHI) funds are being used to subsidise the installation of biomass boilers in larger-than-average properties across the UK.

Figures published by the Department of Energy and Climate Change (DECC) show that biomass boilers account for more than half of all measures installed under the (d-RHI); more than three times the number of solar thermal installs supported under the scheme.

Writing exclusively for Solar Power Portal’s sister site, Next Energy News, Stuart Elmes revealed that the average size biomass boiler installed under the domestic renewable heat incentive is 27kW. Elmes points out that the Institute of Domestic Heating & Environmental Engineers recommends that an 8kW boiler would serve a typical detached house in the UK

Elmes questioned the suitability of subsidising large biomass boilers, asking: “So where are these renewable heating installations? They’re in the mansions of the landed gentry, burning free fuel from woodlands on their estates to heat the family pile and they’re being sent cheques from the taxpayer to do it.

“I’m not interested in the politics of envy. All of this would be fine with me, if it were a stepping stone to some desirable future where all homes are heated by low-carbon technologies, but it’s not. It’s a dead end, and quick and cheap way of box-ticking our EU commitment. Once we’ve run out of Country Life boot rooms to heat, we’ve got nowhere to go. We’ve learnt nothing and developed nothing useful. The supply chain that is being developed is of no relevance to the millions of normal-sized homes we must deal with.”

The latest statistics published by DECC show that there were only 9,078 new d-RHI installation registered from 9 April 2014 to 31 March 2015. Of those installs, 53% were biomass boilers, 28% air-source heat pumps, 13% solar thermal and 6% ground-source heat pumps.

The statistics reveal that there were 4,801 new biomass boilers registered under the d-RHI. Including legacy installs, biomass boilers generated 75,013MWh of energy from 6,173 installs. Almost one third of all biomass boilers registered under the d-RHI were for detached houses, with 22% registered in semi-detached properties. According to the English Housing Survey of 2008 only 17.8% of the UK’s housing stock is detached.

DECC estimates that payments for biomass boilers under the d-RHI will account for an estimated £17.76 million of expenditure between 31 January 2015 to 30 January 2016. The high level of biomass deployment resulted in the technology hitting its deployment trigger which meant that the available tariff for biomass boilers dropped by a fifth on 1 April to 8.93p/kWh.

DECC failed to respond to a request for comment at the time of publication.