One question I had of his idea was whether he rules out carbon sequestration - he doesn't:
The electricity system can be a mix of carbon-free baseload and distpatchable sources like solar thermal with storage, geothermal, wind, solar photovoltaics, biomass, existing nuclear and hydropower, and coal and natural gas power if they are able to capture the carbon.
I have mixed feelings about carbon sequestration. On the one hand, it might occupy the political sweet spot of requiring the least amount of change in power sources in order to eliminate carbon. Instead of needing sufficient political power to completely eliminate the entire coal industry, we just need the power to force them to pay extra to sequester carbon. On the other hand, the technology and most importantly the costs are undetermined. While many environmentalists noted the collapse of the FutureGen project as just one more failure of the Bush Administration, it's also a big setback for carbon sequestration.
So it's an open question in my mind whether carbon sequestration as an unproven technology with unknown costs, but great potential, can play a significant role within ten years. I think Gore's challenge is a reasonable one and that he is completely serious about it, but some results might not be reached by the deadline.