Hydroelectric power stations run backwards to store energy (electrical->potential).
Energy usage of computers is also decreasing, as in mobile devices. There's also anticipated uptake of ARM processors in server farms, because energy usage is a major cost. The advances include advances in energy usage.
We have many options for sources of power; our current choices are mostly preferences.
You're right that energy tech has not advanced at Moore-like rates (nothing but silicon does), but it has matched the accelerating demand for it. When it fails to, we'll see serious research into other power sources. (Cheap energy is a curse.)
Energy usage of computers is also decreasing, as in mobile devices. There's also anticipated uptake of ARM processors in server farms, because energy usage is a major cost. The advances include advances in energy usage.
We have many options for sources of power; our current choices are mostly preferences. You're right that energy tech has not advanced at Moore-like rates (nothing but silicon does), but it has matched the accelerating demand for it. When it fails to, we'll see serious research into other power sources. (Cheap energy is a curse.)