America’s energy sector is going through its biggest crisis–as well as its biggest seismic shift–in modern history. Fossil fuel companies have always dominated the U.S. energy space, and no company has been more dominant than Exxon Mobil (NYSE:XOM) thanks mainly to its powerful John Rockefeller pedigree. Exxon has always been the United States’ most valuable energy company since it began as Standard Oil more than a century ago. But something very strange happened over the last week: Suddenly, a company that has become the face of renewable energy took the mantle of America’s most valuable energy company from mighty Exxon. Florida-based NextEra Energy Inc. (NYSE:NEE) has leapfrogged Exxon and Chevron Corp. (NYSE:CVX) to become America’s most valuable energy company thanks to its growing green energy credentials. NEE boasted a market cap of $147.61B compared to $144.69B and $141.32B by Exxon and Chevron, respectively, by close of business on Wednesday. […]