Renewable sources such as solar, wind and hydropower could fulfill almost 80 percent of the world's energy demand by 2050 with the right policies, according to a U.N. report which won backing from governments on Monday. The 26-page study, by the U.N.'s Intergovernmental Panel on Climate Change (IPCC), broadly matched a draft written by scientists. It was approved by government delegates at talks in Abu Dhabi. Environmental groups hailed the report as a guide to the shift from fossil fuels to combat climate change, a process set to cost trillions of dollars. But they said some draft findings were watered down, partly due to opposition by oil exporters. "Close to 80 percent of the world energy supply could be met by renewables by mid-century if backed by the right enabling public policies," the IPCC said. The report said moves to cleaner energies including geothermal or ocean energy would help cut greenhouse gas emissions, which it blamed for global warming including floods, droughts, heat waves and rising sea levels.