Public support for biofuels is costly and has little impact in cutting greenhouse gas emissions so governments would do better promoting lower energy consumption to fight climate change, the OECD said on Wednesday. Governments should also boost the so-called second generation biofuels that do not use food crops, the Organization for Economic Co-operation and Development said in a report. The study comes as the latest blow to biofuels, made from grains, oilseeds and sugar, which were once hailed for providing a clean alternative to fossil fuels but are now blamed for a surge in food prices.