Britain's Biggest Community Solar Farm Shut Over Grid Fears
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- Neso ordered the Derril Water solar park in north Devon shut for the summer after deciding that surging rooftop solar in the area risked triggering a "thermal overload" on the transmission network
- Derril Water's cooperative board told its nearly 10,000 members the shutdown was "enforced with no warning" on the Friday before Europe's half-term heatwave, and is expected to cost the scheme roughly £2m in lost revenue before a planned September restart
- National Grid confirmed it curtailed local generation after Neso called for a "super grid transformer" to be turned off to keep transmission voltage within safety limits, with specialist voltage-management upgrades delayed from end-2025 to September this year
- The Derril Water board said the network problems had been flagged since 2023 and that new grid equipment originally due by end of 2025 has slipped to September 2025
- The cooperative does not expect compensation or insurance to cover the lost summer revenue; the park was funded by £20m from members and a £22m long-term bank loan
- Derril Water began generating electricity in September last year under its volunteer board after Ripple Energy — which originally launched the scheme offering members average savings of at least £200 a year — collapsed into administration in early 2025
Why it matters: Nearly 10,000 members of Britain's flagship community-owned solar scheme lose an entire summer's revenue — roughly £2m — because grid upgrades flagged since 2023 slipped past their 2025 deadline, exposing how Britain's consumer-energy transition is now bottlenecked by transmission constraints rather than generation capacity.
