The national government said this week that the big surge in electricity prices in the last few days was "temporary" and that prices would drop again.
Ministers ruled out intervening, creating an uncomfortable political situation for the left-wing ruling coalition of PSOE and Unidas Podemos. Both political groups had been extremely critical of the previous conservative government when they were in opposition and when prices last rose in the same way.
On Wednesday this week the price per megawatt hour for consumers on variable tariffs had risen over a third since last Sunday.
More radical Unidas Podemos wants to intervene on prices but its PSOE partner is staying cautious, partly blaming EU rules.