UK Solar CfD Deployment at Record Levels

On December 31, 2025, the Low Carbon Contracts Company (LCCC) reported that UK solar is on track for record CfD deployment in 2026, with PV holding the largest number of contracts of any generating technology. As reported by PV Magazine, the total number of UK solar plants backed by CfDs could more than double in 2026 — a record driven by the AR4 and AR5 allocation rounds that saw solar win more capacity than offshore wind for the first time.

The largest UK PV plant to date, Cleve Hill (350 MW), was commissioned in 2025 under a CfD contract, demonstrating the maturity of utility-scale solar in the UK market. The investment landscape remains diverse: LCCC found 40% of contracted projects are owned by private companies, 38% by infrastructure and investment funds, and 22% by developers — with no state ownership in the sampled projects.

How CfD Strike Prices Affect Project IRR

A CfD provides revenue certainty by fixing a strike price for electricity generated. When the wholesale market price is below the strike price, the generator receives the difference (a "top-up" payment). When above, the generator pays back the difference. The CfD revenue formula is:

  • Total Revenue = CfD Revenue + Market Revenue
  • CfD Revenue = (Strike Price - Reference Price) x Metered Volume (when reference price < strike price)
  • CfD Payment = (Reference Price - Strike Price) x Metered Volume (when reference price > strike price, generator pays)

For the AR5 allocation round, solar strike prices fell to approximately £44-48/MWh, competitive with offshore wind's £40-45/MWh range but above the merchant floor of £20-30/MWh expected during peak solar hours in 2026-2027. The effective capture price depends critically on the hourly generation profile relative to the reference price index.

Key insight: A solar CfD at £47/MWh with 1,100 kWh/kWp specific yield in Southern England generates approximately £51.7/MWh levelized revenue — but only if the project dispatches during hours when the CfD is active. Adding battery storage can shift generation into higher-value periods, increasing effective capture price even under CfD constraints.

Co-Located BESS Under CfD Structures

The key financial question for UK solar developers adding BESS is: does battery storage improve CfD-backed project economics?

In the current UK framework, co-located storage can provide three distinct benefits:

  • Shape the generation profile — store midday solar and discharge during the evening peak (4-6 PM GMT in winter, 7-9 PM BST in summer), converting low-value merchant hours into CfD-qualifying hours
  • Reduce CfD payback risk — when reference prices spike above strike price (typically during winter gas-driven price events), the battery can charge from the grid at low prices rather than the solar array, minimizing CfD payback volumes
  • Stack ancillary revenue — Dynamic Containment (DC), Dynamic Moderation (DM), and Balancing Mechanism (BM) revenues are additive to CfD income and can improve project IRR by 1-3 percentage points

Modeling CfD Revenue in Energy Optima

Energy Optima's financial projection module supports CfD revenue modeling through configurable revenue streams:

  • CfD strike price schedules — input the contract strike price with annual indexation (RPI/CPI-linked)
  • Reference price scenarios — use historical or forecast 8,760-hour wholesale price data
  • Hourly dispatch optimization — the EMS economic optimizer schedules battery dispatch to maximize CfD-qualifying volumes while minimizing payback periods
  • Sensitivity analysis — run scenarios at strike price ± £5/MWh to see IRR impact

For a typical 50 MW solar project co-located with 20 MW/80 MWh BESS in the UK, Energy Optima's optimizer might find that adding storage increases CfD revenue capture by 8-12% while providing £15-25/kW-year in ancillary service revenue — improving project IRR by 1.5-2.5 percentage points over solar-only CfD economics.

Developer Takeaways

  • Check CfD allocation round eligibility for co-located hybrid projects — current rules allow it but metering and settlement requirements differ from standalone solar
  • Model CfD revenue with hourly resolution, not annual averages — the value of dispatch shifting is captured at hourly granularity and annualizing it hides the most critical economics
  • Stress-test P50 CfD revenue against P90 merchant scenarios to satisfy lender requirements for non-recourse project finance