Germany’s day-ahead electricity prices soared by 29% on Wednesday as a heatwave across Europe boosted cooling demand while low wind speeds reduced wind power generation. The lower wind speeds and the resulting lower power output from wind turbines are raising the need to fire up natural gas and coal-fired power production, which is more expensive than wind power generation. An early heatwave is sweeping through northwest Europe with unusually high temperatures these days, lifting demand for air conditioning. Forecasts for Thursday’s…