Just 21MW of large-scale commercial rooftop installations were completed in Q2 2015 – the lowest quarterly deployment within the bracket in two years – prompting the Solar Trade Association to lament the “underperforming” market.

Statistics released by the Department for Energy and Climate Change (DECC) this morning show that 21MW of installations above 50kW in size were installed in the three months ended 30 June, and just 27MW between 10 and 50kW was fitted in the same period.

Not since Q2 2013 have so few large-scale rooftop installations been fitted in a quarterly period, figures which STA business analyst David Pickup said underlined the fact that commercial rooftops are “not the success story we and the government had hoped”.

The Conservative government has continually lauded rooftop solar and secretary of state Amber Rudd said she wanted to trigger a “solar revolution” in the UK, setting the target of having 1 million rooftop installations in the UK. To date rooftop solar remains one of the only solar install methods to have not been targeted by government clampdowns, but the market has yet to reach its expected potential.

Pickup said removing barriers to commercial deployment, such as amendments to the feed-in tariff and regulatory and administrative systems, could help stimulate the market. “It is vital that these are addressed by government,” he said. The STA has also published a ‘Confidence Checklist’ for commercial rooftops, designed to help businesses through the process.

As per DECC’s deployment statistics, there will be no reduction to the FIT for large-scale commercial rooftops from 1 October but 10-50kW installation will receive an automatic 3.5% reduction, taking the tariff down to 11.42p/kWh.