Bill Gates says the government should do more R&D in the energy sector, that a Manhattan Project for sustainable energy won't work and that a carbon tax is necessary. MIT's Technology Review sits down with the co-founder of Microsoft to discuss his participation in the American Energy Innovation Council and what his charity is doing to develop new energy resources. Gates says: "I guess in a vague sense we can say that we want energy that costs, say, a quarter of what coal electricity does and emits zero CO2. We can write that down. But there are many paths to get there, each of which a realist would look at and say, 'Wow, there's a lot of difficult things along that path.' So I think it's very important, both to give poor people cheap energy and to avoid hugely negative climate change, that the U.S. and other governments fund basic research."