Wholesale CfD for Existing UK Solar Farms: What DESNZ Proposes

What DESNZ Is Proposing

On October 28, 2026, the day of the Budget, DESNZ published a joint consultation with the Scottish Government on a Wholesale Contract for Difference, or WCfD. It would offer existing low-carbon generators, which supply about a third of Britain's power, a voluntary fixed-price contract. Government says the aim is to cut consumers' exposure to gas-driven price spikes and give generators more certain revenue.

The contract would fix the wholesale part of a generator's income. If the market reference price is below the agreed strike price, the generator is topped up. If it is above, the generator pays the difference back, as in the standard CfD. Contracts would be awarded only where they represent value for money for consumers.

Does Solar Qualify?

Co-located solar and storage would be treated like the standard CfD if adopted. The metering would need to separate generation from storage, because payments are made only on eligible generation.

How Big Is the Pool for Solar?

Government is minded to set a minimum capacity threshold of either more than 5 MW or more than 10 MW for each asset. Its estimates for RO-accredited solar in Great Britain are upper figures:

At the 5 MW line, government says about 90% of potentially eligible capacity would stay in scope across 37% of sites. At 10 MW it says 81% of capacity across 23% of sites.

How Contracts Would Be Awarded

• Allocation: a one-off sealed-bid, pay-as-clear auction for most generators, run separately from the normal CfD rounds. Government may not publish a maximum strike price or a budget before the auction.
• Timing: the allocation framework and auction are expected towards the end of 2027. Contracts would be awarded in 2028, with payments starting a few months later, after the supplier levy can be forecast.
• Length: government is considering a choice between 5 and 10 years, or a single length for everyone.
• Start date: government assumes 2028 and is asking whether to allow a start window for generators with power purchase agreements or Capacity Market contracts.
• Early exit: only for decommissioning or repowering.
• No capacity reductions after award.
• Strike price indexation: none, partial or full CPI are all under consideration.
• Negative prices: the standard CfD withholds payments when the day-ahead price is below zero, and the consultation asks how that rule would work for existing assets.

The Metering Question

This is the part that lands on EPC and O&M teams. The consultation says it is minded to keep the standard CfD metering rules: Balancing and Settlement Code compliant metering, auditable meter technical details and Balancing Mechanism Unit registration. RO schemes generally use boundary metering with sub-metering where needed, while the CfD needs metering at the point of generation. Some sites will need extra metering equipment, telecoms and data arrangements, and DESNZ says a review of those changes is under way.

DESNZ is also exploring ways to lighten the checks for existing sites, such as relying on regulatory evidence already held, using independent verification of meters and accepting facility descriptions from accredited third parties. Question 17 asks for evidence on the scale, cost and lead times of any upgrades.

What Else Is Moving

• Electricity Generator Levy. The rate rose from 45% to 55% in April and is being extended beyond 2028. At the Budget government confirmed it will last for the longest WCfD contracts, and that a generator holding a WCfD would be exempt from it for the length of the contract.
• Renewables Obligation. The WCfD is not meant to replace or extend the RO. The consultation also asks about a hybrid option where RO generators swap both their wholesale and remaining RO revenues for fixed streams under one contract. A separate DESNZ consultation on Fixed Price Certificates for the RO opened on November 3.

What This Means for EPCs and O&M Providers

• Map client sites against the threshold. Sites above 5 MW are the likely pool, and a single site can bid only on its own metering arrangement.
• Audit metering now. Check whether the site meters at the boundary or at the point of generation, whether meters are BSC compliant and whether the Balancing Mechanism Unit arrangements would suit a CfD contract. That is scope and lead time you can quote before the rules settle.
• Consider responding. DESNZ asks for cost and lead-time evidence on metering upgrades, and EPCs and O&M firms hold that data.
• Repowering is protected. Early exit is proposed for repowering, so a WCfD should not block a replacement project.
• Watch the government response. The final design, including the threshold and the metering rules, will come after December 9.

Where Design Software Fits

If an existing site is a repowering or extension candidate, design software like Reslink produces the layout, bill of materials and single line diagram, and supports ground-mount feasibility up to 1 GW, so a replacement option can be priced early. It does not handle CfD metering, bidding or eligibility.

See the full workflow → Book a demo

Frequently Asked Questions

Q1. What is the Wholesale CfD?

A proposed voluntary contract that would fix the wholesale price existing low-carbon generators receive, topping them up when the market price is lower and taking back the difference when it is higher.

Q2. When does the consultation close?

At 11:59 pm on December 9, 2026. It was issued on October 28.

Q3. Does solar qualify?

Solar PV is one of the technologies government is minded to include, subject to the other eligibility rules.

Q4. How big does a solar farm need to be?

Government is minded to set a minimum of more than 5 MW or more than 10 MW per asset.

Q5. Does it replace the Renewables Obligation?

No. For RO sites the lead proposal covers only wholesale revenue and leaves RO support in place.

Q6. When would contracts start?

Contracts are assumed to be awarded in 2028, from an auction towards the end of 2027, with payments starting a period later.

Q7. What metering would a winning site need?

Standard CfD metering: Balancing and Settlement Code compliant meters, auditable meter details and Balancing Mechanism Unit registration. Some RO sites may need upgrades.

Final takeaway

The Wholesale CfD could put several hundred existing solar farms on fixed-price contracts from 2028, but the threshold, the start date and the metering rules are still open until December 9. For EPCs and O&M providers, the immediate work is a metering audit of client sites and, if you hold cost data, a response to the consultation.

You May Also Like

• UK CfD AR8 2026: Gate 1 vs Gate 2 Solar EPC Guide
• UK Solar and Battery Compliance Calendar 2026-27: Dates and Deadlines
• UK BESS Queue Fee (CMP470): Costs, Co-location and Dates

Sources

• DESNZ, Wholesale Contracts for Difference: consultation (issued October 28, 2026)
• DESNZ, Wholesale Contracts for Difference: consultation (HTML) (October 28, 2026)
• Herbert Smith Freehills Kramer, Breaking the gas link: UK government consults on Wholesale CfDs for existing low carbon generators (November 11, 2026), for the Fixed Price Certificate consultation date

This guide reflects the DESNZ consultation as of November 12, 2026. These are proposals, so check GOV.UK for the government response and the final rules.