The developer bagged 1.2GW of capacity — all to be powered with GE turbines – in the country's second renewables auction.
Spain's energy ministry received offers for triple the 3GW up for grabs, underlining renewed interest in the country's wind market.
The ministry also confirmed that all winning bids were made with "full discount", meaning operators accept zero subsidy and will receive only the wholesale price for electricity generated.
Forestalia had also won 402MW of the 500MW allocated in the country's first ever power auction in February 2016, which broke a moratorium on new capacity in place since 2012.
Following a recent agreement announced this week, GE will also supply Forestalia with the turbines for that first allocation.
Utilities and major wind market players Enel Green Power and Gas Natural have confirmed they won 540MW and 667MW respectively in the auction. Neither has announced its turbine supplier preference.
The development arm of Gamesa, now owned by Siemens, won 206MW and Norvento, a maker of small 100kW turbines, won 128MW.
Details of the remaining 238MW of wind power allocated are yet to emerge.
Trade body WindEurope welcomed the tender results. Giles Dickson, CEO WindEurope said: "The tender results show how onshore wind is today the cheapest option for new power generation. Some may think wind energy no longer needs subsidies."
"But it was the fact the auction offered a guaranteed minimum income that attracted investors and ensured there were enough bids to deliver the low price. And this is the point – it’s not subsidies but revenue stabilisation mechanisms, addressing the risk of wholesale price volatility, that will be critical to the deployment of onshore wind across Europe at competitive costs.
"By offering revenue stability, auctions play a crucial role in enabling investors to finance a project – they’re key to making projects happen."