Biofuels are a less common, and less promising, technology; Brazil met 17% of its transport fuel needs from bioethanol in 2007, but the OECD has warned that the success of biofuels in Brazil is due to specific local circumstances; internationally, biofuels are forecast to have little or no impact on greenhouse emissions, at significantly higher cost than energy efficiency measures.
生物燃料是一项不太常见，没有太大前途的技术；2007年，乙醇在巴西满足了17％的燃料需求，但经合组织警告说，生物燃料在巴西的成功是由于当地的特殊环境，在国际上，生物燃料几乎不会产生温室气体对环境造成影响，其成本与节能措施相比，成本要高很多。