CMP470 is a proposed new charge for holding a place in Great Britain's Gate 2 grid connection queue. Put forward by battery developer Field, it reached Ofgem in its Final Modification Report on 14 July 2026. The charge is called the Oversubscribed Technologies Commitment Fee, or OTCF.

The purpose of the fee is to reduce the over-supply of battery energy storage in the grid connection queue. Britain's Gate 2 battery queue sits at 90 GW against a 29 GW Clean Power 2030 target for 2035. The fee would currently only impact batteries as they are the only technology more than 50% above its target.

When CMP470 was first proposed in April, the floor was set at £10k/MW. The Final Modification Report has since lowered it to £3k/MW, rising in steps to a £25k/MW cap. In the initial proposal, one method was suggested. In the latest proposal, Ofgem will choose between seven different options or scrapping the fee.

Today, holding place in the queue costs a developer almost nothing. The OTCF sets to change that. This update looks at which projects pay first, whether their exit is enough to hold the £3k/MW floor, and what the fee costs a project that stays.

Key takeaways

• CMP470 introduces the OTCF, an extra fee a developer must pay to keep a battery project's place in the Gate 2 connection queue.
• It starts at £3k/MW of a project's capacity and can rise to £25k/MW, down from the £10k/MW floor proposed in April.
• It is meant to clear a queue that is heavily oversubscribed. GB's Gate 2 BESS queue sits at 90 GW against a 29 GW Clean Power 2030 target.
• It falls first on projects that have paid little or no security.
• At £3k/MW the floor is 10% above the peak security a typical battery already posts in its lifetime (£2.7k/MW). The £25k/MW cap is nine times that, so if the queue does not clear and the floor keeps climbing, it becomes a serious cost for anyone who cannot front the cash.
• An estimated 25 GW of the queue holds no security today. If those projects drop out after fee activation, the floor holds at £3k/MW, but the fee only switches off if the queue falls below 36 GW.
• Ofgem has eight options to choose between by mid-August 2026, with the fee starting in July 2027. Developers should price it in now.

What has changed in CMP470 since April

Two things moved when CMP470 reached Final Modification Report stage. The first is that the floor now starts at £3k/MW rather than £10k/MW. In the original proposal, the fee would then step up to a £25k/MW cap, this has remained.

However, the second change is that there is further uncertainty over how the CMP470 fee will be structured. Ofgem now has eight options to consider, rather than just the original proposal. These are listed in the table below.