Iberian power prices dip on weather, nuclear plant

MADRID, March 25 (Reuters) - Iberian power prices declined on Tuesday as temperatures rose after an unseasonable cold snap and a nuclear power plant came back on stream, traders said.

The 1,000-megawatt Trillo plant near Madrid was automatically disconnected from the national grid on Monday afternoon due to a sudden drop in power while water tanks were being cleaned.

Owned by Iberdrola (IBE.MC: Quote, Profile, Research), Union Fenosa (UNF.MC: Quote, Profile, Research) and Portugal's EDP (EDP.LS: Quote, Profile, Research), Trillo was reconnected on Monday evening and was back to 95 percent capacity by Tuesday morning, a plant spokesman said.

"It (the halt) was a bit of a shock which added to a lot of uncertainty yesterday, which is why the pool was a little high. There were many fundamental and technical factors," one dealer said.

The next day wholesale pool price for Spain, which acts as a reference for swaps traded in the over-the-counter market, was set at 56.80 euros per megawatt-hour, down from 60.19 previously.

The drop shrugged off upside pressure from flagging wind power and a rise in demand as holidaymakers drifted back to work after the long Easter weekend.

Wind turbines were supplying 4,590 megawatts by late afternoon, down from an average of 7,000 on Monday, according to figures from the national grid REE (REE.MC: Quote, Profile, Research).

Spain has relied more on wind power in recent months as one of the driest winters in memory has left reservoirs for hydroelectric plants barely half-full.

REE predicted demand for Tuesday would be 759 gigawatt-hours, up from 677 GWh on Tuesday.