Power prices in France turned negative for hours on Tuesday morning amid tepid demand in a struggling economy and increased renewables generation. French intraday power prices traded at as low as -$22.25 (-20 euros) per megawatt-hour (MWh) on the Epex Spot exchange, according to data compiled by Bloomberg. So far this year, France’s power demand has been undershooting projections by grid operator RTE as the French and European economies are seeing little – if any – growth. France, which derives about 70% of its electricity from…