Temporal Correlation

In plain terms

A power purchase agreement that covers a year's consumption on paper could still let an electrolyzer run on fossil grid power at night. RFNBO temporal correlation closes that gap. It requires hydrogen to be made in the same period as the renewable electricity contracted for it.

The timetable in Art. 6 of Delegated Regulation (EU) 2023/1184:

Member States may apply hourly matching on their territory from 1 July 2027, after notifying the Commission.

Typical range

Two provisions soften the rule:

• Storage: electricity from a new storage asset behind the same network connection point as the electrolyzer counts, if the storage was charged in the same period as the contracted renewable electricity was produced.
• Low-price hours: the condition is treated as met in any hour when the bidding zone's day-ahead price is at or below €20/MWh, or below 0.36 times the price of an EU ETS allowance.

These rules apply to grid-connected plants using PPAs. A directly connected, off-grid plant draws only its own renewable power, so matching is built in.

Why it moves LCOH

Hourly matching removes the option to fill renewable gaps with grid power. The electrolyzer must follow the contracted renewable profile, which lowers its capacity factor, or the project must add batteries or hydrogen storage. Either way, LCOH rises, most on solar-only sites.

Common mistake