* Wind power exceeds 16,000 MW, 43 pct of demand
* Day-ahead base 22.69 euros/MWh, down
* Wind set to fall on Thursday, may weigh on pool (Adds details previous records, background)
MADRID, April 18 Spanish spot power prices sank to their lowest levels in two years on Wednesday as cheap supplies of wind power climbed high above previous records.
The Iberian Electricity Market's (Mibel) spot exchange, OMIE, set the day-ahead "pool" price at 22.69 euros ($29.82) per megawatt-hour, down 11.75 euros on the day and the lowest for a full working day since it fixed a price of 21.41 euros for April 8, 2010.
By 1520 GMT, Spanish wind parks - the world's fourth-most productive - were producing 16,513 megawatts, or enough to meet 43.3 percent of demand, according to data from national grid operator REE.
That compares with a previous record of 14,962 MW set on Nov. 9, 2010.
REE officials said they were waiting for wind power to peak before they could establish how high the new record would be.
Wind power weighs on the "pool" price because it displaces costlier coal- and gas-burning plants from the generation mix.
Spain's windy weather in recent days momentarily pushed up wind power's share of total demand to a record 60.5 percent on Monday, although that was when demand itself was low, at 3:48 a.m.
Wind power has provided 18.6 percent of electricity needs for the year so far in Spain, which accounts for 85 percent of the Iberian market.
The "pool" may rebound on Thursday because REE predicts wind power will drop to around 12,000 MW by peak hour.
Spain's eight nuclear power stations were all working normally and generating 6,458 MW between them, or 16.9 percent of demand, according to data from REE and the CSN safety watchdog. ($1 = 0.7610 euros) (Reporting By Martin Roberts; Editing by Nigel Davies)