MADRID, July 1 (Reuters) - Iberian prompt power declined for the second day in a row on Wednesday amidst renewed forecasts that supplies of cheap wind power would recover from very low levels, while a retreat by oil weakened futures contracts.

Spanish wind parks -- the world's third-largest -- were expected to generate up to 3,000 megawatts on Thursday, rising from 290 MW at midday on Wednesday, which was the equivalent of just 0.7 percent of demand.

Wind power has provided 43 percent of Spain's electricity and it sways the power market.

Brent crude was trading slightly lower than at around midday on Tuesday, at about $70.50 a barrel and this lowered prospective costs for oil and gas needed to drive half of Spain's generators.

Baseload calendar-year 2010 was reported changing hands at at 46.45 euros/MWh in early over-the-counter market deals, down some 0.55 from the latest price in the sporadic trade in the prior session.

Six of Spain's eight nuclear power stations were working normally and providing 5,242 MW between them, or 12.2 percent of demand, according to data from the CSN nuclear regulator and national grid operator REE.

The Asco I and Vandellos II plants were both refuelling. Each generates 1,000 MW when running normally.

(Reporting by Martin Roberts, editing by Anthony Barker) -- For more prices click on -- For up to date demand and wind energy generation data, see Red Electrica's web page http://www.ree.es/index_de.html -- For more details of nuclear power stations, visit the regulator's web site http://www.csn.es -- For more details of the pool, see market operator OMEL's web page http://www.omel.es/frames/es/index.jsp -- For the futures market, see Portuguese operator OMIP's web page http://www.omip.pt/precos_volumes.php?id=10 ($1=.7107 Euro) Keywords: MARKETS IBERIA/POWER

(martin.roberts@thomsonreuters.com; +34 91 585 2130; Reuters Messaging: martin.roberts1.reuters.com@reuters.net)

COPYRIGHT

Copyright Thomson Reuters 2009. All rights reserved.

The copying, republication or redistribution of Reuters News Content, including by framing or similar means, is expressly prohibited without the prior written consent of Thomson Reuters.