The Cabinet Office has yet to complete a single rooftop solar installation despite outlining plans to fit 1GW on the government estate 18 months ago, Solar Power Portal has learned.

In April last year DECC published part two of its Solar Strategy document, included within which was an aim to install 1GW of solar PV generating capacity on the government estate through what was titled a “major programme” to be led by both DECC and the Cabinet Office.

SPP launched a Freedom of Information request last month as part of research into the government’s solar strategy progress and the Cabinet Office’s reply revealed that no prospective installations have progressed to the final stages.

“In regards to the number of rooftop solar PV installations the Cabinet Office has committed to date, as per the Solar Strategy document unveiled in April 2014, if it is Final Investment Decision, then the answer is none,” the Cabinet Office stated.

The department does however qualify that admission by stating that it is continuing to work with various other governmental departments and public sector bodies on solar PV projects, “several of which do include rooftop installations in their design”.

SPP also understands while there have yet to be contracts offered, there are individual projects that could be realised in the coming months.

Any projects that are still to get off the ground by 1 January will stand to be subject to dramatically decreased feed-in tariff rates as per the FiT consultation, which closed last Friday. The rates proposed have been derided as uneconomic for most installations, which pour considerable question onto whether or not such projects would go ahead given the government’s need to “balance the books”.

Also included in the FiT consultation were proposed deployment caps, effectively prohibiting more than 569MW of rooftop solar from claiming the generation tariff in order to cap spending at a maximum of £100 million. Installations made outside of this cap would only be eligible for the export tariff, placing even more strain on rooftop solar feasibility.

A Cabinet Office spokesman had yet to respond on this line of questioning at the time of publication but James Owen, whose company Public Power Solutions has been collaborating with the Cabinet Office and supplying it with procurement systems, said the types of projects envisioned by the Cabinet Office could go ahead without the need for subsidy.

“We have been speaking to the Cabinet Office for a considerable period of time, a number of projects have been put forward in the wider government estate which will work in a post-subsidy world because they have the potential to be private wire connections. Those conversations are still ongoing and will be procured in a compliant manner using our dynamic purchasing system,” Owen said.

The admission places into serious doubt the government’s commitment to renewables deployment. While the Conservative Party has led a majority government since May, it was in coalition with the Liberal Democrats in the previous government and the Cabinet Office was very much a Conservative-led department.

It also flies in the face of energy secretary Amber Rudd’s much-vaunted desire to trigger a “solar revolution” on the UK’s rooftops, outlined days after her appointment at DECC but continually undermined since.

Then-energy secretary Greg Barker, launching the Solar Strategy document, said: “There is massive potential to turn our large buildings into power stations and we must seize the opportunity this offers to boost our economy as part of our long term economic plan.

“Solar not only benefits the environment, it will see British job creation and deliver the clean and reliable energy supplies that the country needs at the lowest possible cost to consumers.”

While no rooftop installations have been made, at least one major ground-mount development is understood to contribute towards the intended target of 1GW; the 70MW solar farm constructed at DTTC Lyneham. But even that project was marred in controversy as the government rushed through its development prior to a looming Renewables Obligation deadline.

Speaking to Solar Power Portal on the subject, Green Party MP Caroline Lucas said: “It stands to reason that a Government which slashed support for renewables is also failing to fulfil its commitments when it comes to installing solar on their own buildings.

“If ministers hadn’t backtracked on this commitment, they’d see that installing solar panels is a great way of reducing energy bills. And it might help them realise that their current plans to slash support for solar power need to be radically rethought to keep people in jobs and ensure businesses and households all around the country do not miss out on the benefits of generating their own energy,” she added.