Policy makers around the world, in both developed and developing economies, have to make decisions today about how to avoid greenhouse gas emissions and the calamitous effects of climate change. These decisions are not only about avoiding tons of greenhouse gases. They are also about the need to avoid the cheapest tons first. Drawing on experience across the globe, this paper presents a broad range of policy choices, which can be tailored to the specific circumstances in which they are implemented. It highlights examples of best practices for technology research and development, and for policy initiatives to foster deployment of those technologies that can lead to a decarbonized electric power sector.