The British solar sector is facing a long-term growth threat due to restrictions on large-scale solar energy deployment and battery storage capacity. Solar Energy UK, along with ten major industry players, has sent a letter to Energy Secretary Ed Miliband, warning of an investment “cliff edge” beyond 2030.

The letter highlights that the Clean Power Action Plan 2030 (CPAP), published in December, could choke investment in utility-scale solar farms and virtually halt the development of battery energy storage systems (BESS) after 2030.

Chris Hewett, Chief Executive of Solar Energy UK, leads the appeal, backed by key industry players such as Low Carbon, EDF Renewables, Boom Power, and Innova Renewables.

A Slowing Market with Multi-Billion Consequences

Industry data shows that the UK’s solar generation capacity reached 20.2 GW by the end of 2024. However, CPAP projects an increase to 47 GW by 2030, with an additional 9-10 GW from sub-5 MW solar systems, mainly installed on rooftops.

Beyond that, growth is set to stall, with only 22.4 GW of additional large-scale solar systems expected by 2035. Battery storage will also slow significantly, increasing to 27.1 GW in 2035 but only adding 1.6 GW beyond that.

“The industry faces the prospect of developers working on projects with grid connection offers for 2031, 2032, and 2033, only to be told that their green, low-cost projects exceed policy limits,” the letter warns.

A Government Miscalculation

Industry leaders argue that the 2035 capacity limits were set without prior consultation, denying stakeholders the opportunity to provide feedback before CPAP’s publication. Moreover, the letter states that current targets repeat past planning errors made by the National Energy System Operator (NESO), which could lead to higher energy costs.

The industry insists that these projects are essential for the UK’s energy security, ensuring competition in Contracts for Difference (CfD) auctions and offsetting potential delays in other renewable technologies.

“We do not believe these factors have been considered in NESO’s advice or in the Government’s CPAP,” the letter states.

A Call to Action: Lifting Limits and Expanding Subsidies

To mitigate these risks, the industry proposes two key measures:

1. Lifting the 17 GW cap on solar energy connected to the transmission grid by 2035.
2. Expanding subsidies for battery energy storage systems (BESS).

If no action is taken, Solar Energy UK warns that CfD prices will rise, directly impacting consumers’ energy bills.

“We would also like to ask whether there are mechanisms for holding NESO accountable, to ensure such contradictions do not arise again in the future,” the letter adds.

A Narrow Timeframe to Adjust Policy

The existing capacity limits could be revised in the upcoming Strategic Energy Spatial Plan, due by late 2026. However, the sector fears that this timeline is too tight to avoid a significant investment slowdown.

The next grid connection offers will be granted in Q3 2027, leaving very little time for project approvals, procurement, and construction before 2035.

“This will cause an immediate investment pause and delays in project connections in the early 2030s,” the letter warns.

Limited Opportunities to Correct Course

NESO is set to implement the 2035 capacity limits as strict constraints for utility-scale solar projects from May this year. This leaves very little time to adjust policies and prevent a severe slowdown in the industry.

Industry Remains Committed to Collaboration

Despite these challenges, the UK solar industry remains optimistic about its future. Industry stakeholders are eager to collaborate with the Government to unlock the full potential of solar energy and battery storage, ensuring a sustainable and cost-effective energy transition.

Solar Energy UK urges Miliband to take immediate action to revise capacity limits, ensure adequate subsidies, and enable the continuous growth of the solar and energy storage sector.

Without prompt government intervention, the UK risks losing £26 billion in investment and compromising its leadership in the global energy transition.