Spain's Data Center Rules Could Require 50 GW of Renewables

Spain's plan to tie data center growth to new renewable capacity could demand far more generation than the facilities consume. According to a study by consultancy EY, meeting the draft royal decree's requirements for the 3.5 GW of data center demand expected by 2030 would take a portfolio of 49.8 GW of solar, wind and storage.

What the decree requires

Both the draft presented in August and the softer revision released in recent days keep the same core conditions. At least 80% of a data center's electricity must come from new solar or wind capacity (renewable additionality), and 80% of consumption must be backed hour by hour (hourly correlation). Producing plenty of renewable energy over a full year is not enough: supply has to match demand in the difficult hours too.

That is hard because data centers run around the clock while renewables are intermittent. Output at 3 pm on a sunny summer day is very different from a windless night. To cover the gaps, operators can combine extra generation with storage.

The numbers in EY's simulation

Under EY's assumptions, the 49.8 GW portfolio would consist of 26.8 GW of solar photovoltaic, 8.8 GW of wind and 14.2 GW of battery storage. That is about 14 times the electrical capacity of the data centers it is meant to supply.

The study also flags side effects. The model estimates 19,742 GWh of annual surplus energy and a rise in system curtailment of at least 16%, which EY says could erode the profitability of existing renewable plants. Supply costs for data centers could reach 133.07 euros/MWh, against 55 euros/MWh on the futures market for that year, or 2.4 times higher. That could be passed on to digital services and make them less competitive.

Industry pushback

Despite the milder revision, the sector is still considering a legal challenge to the project. The findings suggest that installing 1 GW of renewables per GW of data center demand would not satisfy the rules as drafted, which puts pressure on the government to revisit how it defines coverage.