A letter from a group of ten companies led by Solar Energy UK has warned UK Energy Secretary, Ed Miliband, about a potential "cliff edge" in investment in cheap, clean solar energy and battery systems after 2030. 4p3e6w

According to the letter sent to the Labour Party member, a combination of policies is putting £26 billion of investment at risk and could lead to higher energy bills.

Slowing the deployment of solar parks and grid-scale energy storage at the beginning of the next decade poses a risk to the economy as a whole, the statement adds.

According to the g companies, the December Clean Energy Action Plan 2030 (AP) would stifle investment in ground-mounted photovoltaic energy and practically block the development of battery energy storage systems (BESS) after 2030.

The industry has estimated that the UK's solar generation capacity at the end of last year was 20.2 GW. An annex to the AP forecasts that the total solar capacity for Great Britain will increase to 47 GW by 2030, plus another 9-10 GW of systems under 5 MW, which are expected to be built mainly on rooftops. After that, deployment would slow down, with another 22.4 GW of systems over 5 MW expected to be installed by 2035. By that time, 27.1 GW of BESS is expected to be operational, up from the current 5 GW. But by 2035, only an additional 1.6 GW is forecast, which represents a drastic loss of pace.

The industry faces the prospect of developers working on projects with connection offers for 2031, 2032, and 2033, only to be told that their cheap and green projects exceed the requirements.

The targets risk making the same mistake as the National Grid ESO figures that backed the action plan, which would have been an even greater brake on the sector by setting lower targets.

Since the 2035 limits were not included in the initial ESO advice, there was no opportunity to provide before the plan was published. "We believe that many of these projects will be necessary to for the loss of projects, to ensure competition in the Contracts for Difference auctions and in case other technologies turn out to be slower to deliver or more expensive; we do not believe these factors were considered in the ESO's advice or in the Government's AP."

The group wants the 2035 transmission network solar limit, set at 17 GW, to be increased, as well as more subsidies for batteries. "Without this, the industry, the Government's targets, and consumers will suffer poor outcomes, as the prices for Contracts for Difference will be higher and energy bills will rise.

"We would also like to ask whether there are mechanisms in place for the Government to hold ESO able to prevent these contradictions from happening in the future," the letter states. The 2035 targets are expected to be replaced by the next Energy Spatial Strategic Plan, which will be presented by the end of next year. The next network connection offers would be issued in the third quarter of 2027.

But this leaves very little time for approval, acquisition, and construction for the period up to 2035. "Therefore, the current plan will cause a pause in investment now and a pause in connection projects in the early 2030s," the letter says. As ESO will implement the 2035 projections as strict limits for grid-scale photovoltaic energy starting in May, there is little time to resolve these issues.

The letter is signed by the CEO of Solar Energy UK, Chris Hewett, and ed by some of its most important , including Low Carbon, EDF Renewables, Boom Power, and Innova Renewables.