Britain's two-way power contract rewards low-carbon energy only when it is cheap

Low-carbon plants are capital-hungry and face volatile wholesale prices, so investors demanded a high return premium and consumers picked up the cost.

The UK's Electricity Market Reform introduced Contracts for Difference: contracts between generators and a government-owned company at a strike price set by competitive auction.

The generator still sells into the market as usual. When the reference price is below the strike, the state pays the gap; when it is above, the generator pays the surplus back. That stabilizes revenue for investors and caps the cost to consumers in both directions.

National Grid ran the first allocation round as delivery body, with transparent published results in February 2015 and separate budgets for established and less-established technologies, so support went to the projects that bid lowest relative to their cap.

Guarantee the gap, not the price — and claw back the surplus

A two-way contract gives cheap capital, the largest lever on the cost of clean power.

The clawback protects consumers when wholesale electricity prices spike.

Competitive auction rather than a fixed tariff reveals the true cost and keeps support minimal.

Making a supply-chain plan a precondition pushes innovation and lowers costs over time.

Stabilize the risky part — the gap — and let the market set the rest.

CfD auction rounds drove offshore-wind prices to record lows and became the UK's main support mechanism for low-carbon power; the two-way contract design has been widely copied by other countries.