Spain proposes 80% hourly renewable power matching for data centres

Spain is proposing a more demanding test for the renewable electricity supplied to data centres: matching consumption hour by hour, not simply buying enough green power over a year. A draft Royal Decree opened for consultation on 27 August would link new data-centre demand to additional renewable generation.

For developers and power buyers, the central issue is the shape of supply. A contract that covers annual demand may still leave substantial gaps between when renewable power is produced and when a facility needs it.

What the draft would require

The proposed regime covers data centres with electrical power above 1 MW. At least 80% of electricity consumed in each hour would need to be backed by an equivalent volume of renewable electricity generated in that hour. Self-consumption arrangements and renewable power purchase agreements are among the proposed routes to compliance.

Additionality is a separate condition. Each new MW of demand capacity would need at least 1 MW of new renewable capacity, commissioned no more than 18 months before the data centre enters operation. This is intended to make expansion support new generation rather than merely redirect existing renewable output.

As of 28 August, these are proposed rules, not binding law. The consultation closes on 4 September 2026. The text includes transitional provisions and links the regime to the electricity mix exceeding 90% renewable generation. Developers will need to assess the final rules and their application to individual projects once adopted.

An annual PPA is not the same as hourly coverage

Consider a solar farm supplying a customer that operates around the clock. Strong daytime output can help balance its annual electricity purchases, but that does not establish renewable coverage after sunset. The timing gap remains even if annual contracted generation equals annual consumption.

Under the proposed approach, a buyer would need to examine more than the PPA's headline volume and price. Delivery profiles, shortfalls and the allocation of balancing costs would become central commercial questions.

Storage has a role, but is not a shortcut

Our assessment is that hourly matching could strengthen the case for combining solar, wind, storage and flexible demand. A battery can shift energy towards hours when it is more useful to the customer. That operational benefit should not, however, be confused with automatic regulatory compliance.

The origin of the electricity, metering arrangements and the treatment of associated storage all matter. Charging from the grid does not by itself establish renewable provenance. Nor does the proposal impose a universal requirement for every data centre to install a BESS.

The draft also provides for network-charge surcharges in cases of non-compliance. Losing access and connection permits is reserved for significant, repeated breaches and involves a formal procedure; it is not the automatic consequence of an isolated hourly shortfall.

Why the Bulgarian market should pay attention

This is a Spanish proposal, not a change to Bulgarian law or a uniform European obligation. Its commercial message nevertheless travels: large electricity buyers may increasingly value the timing and reliability of renewable supply alongside installed capacity and annual yield.

For Bulgarian project owners, that is a reason to make production profiles, storage options and delivery commitments part of early buyer discussions. It is not evidence of guaranteed demand or higher returns. The opportunity lies in designing an offer around a customer's actual consumption, with clear responsibilities for the hours when renewable production falls short.