* France net imports from Germany rise, exports to UK up
* Franco-German power link at max capacity half of the time
* Slow economy, energy efficiency weigh on power demand
* Growth of wind and solar energy continues to slow (Adds quotes, detail on interconnections and renewables)
By Michel Rose
PARIS, Jan 23 (Reuters) - France's net electricity exports rose by 6.8 percent in 2013, making it Europe's biggest power exporter, although it remained a net importer from Germany for the second year in a row, French power transmission grid operator RTE said on Thursday.
Germany's power export surplus with France widened to 9.8 terawatt-hour (TWh) in 2013 from 8.7 TWh in 2012, when the German surplus first appeared.
Germany's large and growing renewable power output, which has priority access to the electricity grid, spills over into France through power interconnections, which RTE said were increasingly pushed to their capacity limits.
"Our country's interconnections are more and more in demand, at some moments being near saturation," RTE chief Dominique Maillard told a news briefing, adding that interconnection capacity limits between France and Germany had been reached about half of the time in 2013, four times as much as in 2009.
He said that the average spot power price in France is lower than in all neighbouring countries except Germany, where prices are lower essentially because of renewable energy produced at a marginal cost that is close to zero.
The current interconnection capacity between the two countries is about 4.2 gigawatts per hour. One gigawatt roughly corresponds to the capacity of one nuclear plant.
In 2013, France's net exports reached 47.2 terrawatt/hour (TWh), and the country registered a power surplus with all its neighbours except Germany, RTE - a subsidiary of former power monopoly EDF - said in its annual power report.
Exports to Britain and Belgium rose on the back of high gas prices in these countries, making nuclear electricity produced by EDF's 58 French reactors more competitive, RTE said.
ECONOMIC SLOWDOWN WEIGHS
French power demand rose by 1.1 percent year-on-year to 495 TWh, due to colder temperatures on average in 2013 compared to 2012. When corrected for the weather impact, French power consumption edged 0.5 percent lower to 480.4 TWh, RTE said.
Consumption by households, professionals and SMEs edged up 0.3 percent last year, a sharp slowdown compared to the 2.4 percent increase of 2012 and the almost continuous annual power demand increases seen since 2002.
"Two factors come to play: an economic one, with households' income remaining stable, and a more structural one. When the French buy a new fridge or a washing-machine, they probably pay more attention to its power consumption," Maillard said.
Demand from industry continued to decline, though at a slower pace than previous years, falling 2.5 percent in 2013 after 4 percent drops in both 2011 and 2012.
Power demand fell most in the paper, automotive and steel industries, as the economic crisis led to plant closures and lower manufacturing production, RTE said.
RTE also said power demand had become more sensitive to temperatures changes because of the high use of electrical heating and air conditioning, with a one degree Celsius change pushing French electricity consumption by 2.4 MW up or down on average, from 2.3 GW previously.
On the production side, output rose by 1.7 percent to 550.9 TWh in 2013, rebounding slightly after a minor decline in 2012.
In 2013, French nuclear power output edged down 0.3 percent but still made up 73.3 percent of total French electricity production, while renewable power production including hydropower rose to 18.6 percent of production.
Excluding hydro, renewables accounted for only 4.8 percent of French power production, of which 2.9 percent came from wind energy, 0.8 percent from solar and 1.1 from other renewables.
Wind power capacity reached a total of 8,140 MW at the end of 2013, but growth in the sector slowed for the fourth year in a row, with just 630 MW of new capacity added, from 821 MW in 2012 and a high of 1,247 MW in 2009.
Solar saw a similar evolution, with total capacity growing just 743 MW to 4,300 MW, compared to capacity growth of 990 MW in 2012 and 1,688 MW in record year 2011.
In Germany, new solar panel installations fell by more than half last year and total capacity rose to 35.7 GW. Figures for German 2013 wind capacity are not yet available, but in 2012, the country added 2,439 MW of capacity, boosting the total to 31.3 GW.
(Editing by Geert De Clercq, editing by David Evans)