US President Barack Obama on Wednesday stepped up his commitment to renewable energy to help tackle climate change, including alternatives such as clean coal technology and maize-based ethanol as part of the solution. Obama announced that the US had finalized plans to more than double renewable fuel production in the US to 36 billion gallons (172 billion litres) by 2022. For the first time, any fuel included in the mix must meet a threshold of reducing greenhouse gas emissions blamed for global warming by 20%. “The bottom line is this: I am convinced that America can win the race to build a clean energy economy,” Obama was quoted as saying by the press at a meeting with state governors in Washington. But Obama said he was confident that coal could remain part of the country’s energy mix.