PARIS, Dec 29 (Reuters) - European electricity contracts for January delivery posted gains on Friday as weather forecasts raised expectations for a cold spell that could spur demand.
* The German contract for January delivery rose 1.25 percent to 40.40 euros ($48.41) a megawatt-hour (MWh). The equivalent French price rose 0.09 percent to 57.75 euros/MWh.
* "Latest forecasts show it would be colder than expected and prices have picked up. That is why the German contract is trading above 40 euros," a trader said.
* Prompt electricity contracts for early next week delivery diverged as demand is Germany was expected to rise sharply after the New Year bank holiday.
* The German baseload electricity contract for Tuesday delivery , the first business day after New Year, gained 9.60 euros to 33.10 euros/MWh, compared with the price paid for Friday delivery.
* The French spot contract for Tuesday traded at 40.50 euros/MWh, down 4 euros compared with the Friday delivery.
* German average power consumption is expected at 67.6 gigawatts (GW) on Tuesday, according to Thomson Reuters data, compared with 66.7 GW on Friday. In France, average demand is seen at 60.9 GW compared with 66.5 GW on Friday.
* Peak electricity demand is expected at over 71.6 GW in France on Tuesday, according to a separate forecast by French power grid operator RTE, which expects peak demand to remain above 71 GW throughout the week as the weather gets colder.
* On the supply side, German solar and nuclear output is expected to be lower on Tuesday.
* French nuclear power availability is steady at 88.78 percent of capacity on Friday following delays in the restart of EDF's Tricastin 1 and 2 nuclear reactors by four days to Jan. 2.
* Further along the curve, the German year-ahead Cal'18 contract , the European benchmark, gained 0.40 percent to 37.90 euros/MWh.
* The less liquid French year-ahead contract was flat at 44 euros/MWh.
* Carbon emissions rights for December 2017 expiry fell 1.49 percent to 8.09 euros a tonne. ($1 = 0.8345 euros) (Reporting by Bate Felix; Editing by Kevin Liffey)