The early closure and grandfathering of Renewable Obligation support for sub-5MW projects will apply to commercial rooftop installations as well as ground-mounts, the Department for Energy and Climate Change (DECC) has confirmed.

Last week DECC revealed controversial proposals to close RO support for sub-5MW solar projects a year earlier than planned on 1 April 2016. The department also confirmed that it intended to remove grandfathering from such projects to “avoid potential overcompensation of further solar PV deployment” prior to the closure.

The removal of grandfathering would mean that projects that had not been accredited under the RO before 22 July 2015 and did not qualify for the grace period could see the RO level change over the lifetime of the project.

The documentation was released by DECC last Wednesday but there had been confusion over whether the changes would apply to commercial rooftop installations given how the RO is split between ground-mount and rooftop projects.

Speaking to Solar Power Portal, a DECC spokeswoman confirmed that the changes would apply to rooftop projects as well as ground-mount but added that it was “important to note that it is not retrospective”.

Confirmation that grandfathering will apply to rooftop solar projects under the RO is likely to have significant repercussions on the market’s prospects due to the need for legal and business agreements to cover the life expectancy of the installation. Companies deploying rooftop solar projects without grandfathering could find it difficult to source investment due to the subsidy uncertainty.

Last week the Solar Trade Association lamented the lack of progress the UK’s rooftop market has made, sentiments which were echoed earlier today by Green Party London Assembly member Jenny Jones who said the “chaotic and unpredictable” policy decisions made by the government were creating instability in the market.