One of the misconceptions that clean energy advocates have is that wind and solar power can simply replace coal and nuclear as our sources of electrical power. The problem is that the current systems can be throttled up or down depending on how much energy is needed by consumers. This is much harder to do on a distributed basis. Worse, some of the best places to harness wind and solar energy are far away from population centers, and our current power transmission grid is woefully inadequate to this task and will require many billions of dollars to fix.
However, some recent innovations may help. An MIT research team is breaking ground on energy storage on a household level. Currently when you generate surplus electricity, it goes back onto the grid. In turn, the energy companies throttle down their production levels--because the grid cannot store energy for significant periods of time. Worse, the throttling process is complicated and expensive. If energy could be stored at the household level it would be more efficient, less expensive, and ultimately cleaner--and free the consumer from the power grid altogether.