(Bloomberg) -- Power prices across Europe soared as a slump in wind generation forces nations to fire up plants running on more expensive fossil fuels.Most Read from BloombergParis Restricts Through Traffic in City CenterFrom Housing to Immigration, Key Ballot Initiatives and Local Races to FollowThe Polish grid PSE triggered a so-called state of emergency for its power market on Wednesday. Much of northwest Europe is experiencing warmer-than-average temperatures, but a high-pressure system has