Residential solar deployment in the UK slumped to its worst Q4 on record in 2016, swelling the carried-over <10kW capacity to nearly three-times its originally allocated capacity.

Statistics released by industry regulator Ofgem late on Friday revealed that total deployment for Q4 under the domestic (<10kW) band amounted to just 20.85MW, spread across a total of 8,298 systems.

With 2,546 systems installed across the band in October and a further 2,756 installed in November, December deployment will have reached 2,701 separate systems across the country.

Deployment of that scale – just 16.3% of the total cap limit of 127.7MW – has meant that the <10kW deployment cap for Q1 2017 now stands at roughly 159.7MW, roughly three times what the cap would have otherwise amounted to.

It also represents the worst Q4 for residential solar PV deployment on record in the UK, according to Department of Business, Energy and Industrial Strategy statistics.

Around 190MW of <10kW solar was connected in Q4 2015, with a significant 175MW in the standard <4kW band as consumers rushed to take advantage of more lucrative tariff rates prior to the scheme’s reforms. Year on year, deployment has therefore fallen by nearly 90%.

Deployment remains substantially down from that in Q4 2014 when 119MW was installed, and in Q4 2013 when 85MW was deployed under the same band.

BEIS statistics show that 66MW of solar was installed in Q4 2012 under the corresponding band. Q4 2011 deployment is slightly skewed owing to the dramatic halving of the feed-in tariff outlined on 31 October 2011 to come into effect from 12 December 2011, creating a surge in installs. Roughly 375MW of solar was installed in that band in Q4 2011, the majority of which was installed throughout November.

But even in 2010, in UK solar’s relative infancy, the industry still installed more small-scale rooftop solar. According to BEIS circa 25MW of <10kW solar was deployed in Q4 2010, some 20% more than in Q4 2016. 

The figures stand to defy the government’s repeated rhetoric that solar PV deployment in the UK has remained strong despite the government’s cuts to feed-in tariff support. Energy secretary Greg Clark has insisted that confidence in the industry remains high, but has also acknowledged that his department would continue to monitor deployment levels under the feed-in tariff to ensure the scheme remains viable.