The full 1,700-page regulation, a summary of its long-awaited renewables regulation, was sent to regulator CNMC for a 20-day consultation period. It has not yet been made public.
The summary alone, nonetheless, discloses an act of institutional "retroactive looting", Spanish wind association AEE told Windpower Monthly.
Investors behind all of Spain's 22.6GW of online wind capacity were drawn by the state's promise of maintaining feed-in tariffs for 20 years.
Just over 8.4GW was online by end-2004. Under the new regulation, all that capacity will now only receive the wholesale power market price.
The proposed regulation, to take immediate effect, establishes 1,600 parameters for calculating renewables remuneration. It fleshes out a June 2013 law replacing all renewables feed-in tariffs with a remuneration based, instead, on a "reasonable profit" of 7.5% across plant lifecycle.
"It is the most harmful policy dictated against wind in any country," said the AEE, which is calling for EU intervention.