A report shows that solar energy was the fastest-growing source of power last year, accounting for almost two-thirds of net new capacity globally. The International Energy Agency said Wednesday that the rise was due to a boom in photovoltaic panel installations, particularly in China, thanks to a drop in costs and greater support from governments. It is the first time that solar energy growth surpasses any other fuel as a source of power. Coal in particular had continued to grow in recent years despite global targets to reduce carbon emissions. The IEA said solar panels capacity grew 50 percent last year, with China accounting for almost half the expansion. The country has become a leader in renewable energy production, with the United States the second-largest market.