On the afternoon of 12 August 2026, the UK system operator paid £875 per megawatt-hour to Uniper's Connah's Quay gas plant, about 4.1 times the prevailing market price, to secure backup generation during a solar eclipse.
Why the premium was required
The Guardian reported that the eclipse was expected to block up to 95 % of sunlight in parts of the United Kingdom, sharply curtailing solar output. NGESO, the National Grid Electricity System Operator, forecast a shortfall of roughly 1,200 MW between 4 pm and 8 pm on the day of the eclipse. To avoid a supply gap, the operator contracted the Flintshire-based plant at the elevated rate.
Scale of the expected shortfall
The estimated 1,200 MW deficit is comparable to the combined capacity of several large nuclear reactors, underscoring how a brief loss of solar generation can strain the grid.
Implications for a renewables-heavy grid
The premium paid illustrates the cost of emergency capacity when intermittent renewables dominate generation. While the market price that evening was around £212 /MWh, the operator chose to pay a multimillion-pound premium, a figure it did not disclose, to guarantee supply. The episode raises questions about whether existing capacity mechanisms adequately account for predictable, though rare, events such as solar eclipses.
What comes next
NGESO has not said whether it will adjust its capacity procurement rules in response to the eclipse. The issue is likely to be examined by the regulator as it reviews how to ensure reliability without imposing excessive costs on consumers.
| Item | Value |
|---|---|
| Price paid to Connah's Quay plant | £875 /MWh |
| Market price that evening | £212 /MWh |
| Premium multiple | ≈4.1× |