Gates has looked at a number of power options, including Sadoway's liquid metal batteries and the TerraPower "nuclear candle" breeder reactor.
I'm not convinced that nuclear's the way to go, but we know how to create working plants based on both uranium and plutonium fuel cycles, with thorium looking pretty viable. How economically feasible and long-term safe they are remains an open question, though I'd consider them as at least bridge technologies to whatever human's next stable-stage energy mix is.
The best fusion reactor design I've seen is a third-generation design that's been in long-term field trials with wide deployment, and can be found in an operational model 8 light minutes away. The primary challenge is figuring out how to plug it into human power grids.
I'm not convinced that nuclear's the way to go, but we know how to create working plants based on both uranium and plutonium fuel cycles, with thorium looking pretty viable. How economically feasible and long-term safe they are remains an open question, though I'd consider them as at least bridge technologies to whatever human's next stable-stage energy mix is.
The best fusion reactor design I've seen is a third-generation design that's been in long-term field trials with wide deployment, and can be found in an operational model 8 light minutes away. The primary challenge is figuring out how to plug it into human power grids.