At the powers involved you might melt quite a bit of the ground :). But some heating plants for centralized house heating do have electric water heaters, which are used, as soon as the electricity spot price goes below a certain number - the rest of the time they heat with gas.<p>These spikes would go mostly away, if more coal plants get replaced by gas plants which can be switched off very quickly. I guess, as soon as there are more of those days, this shift is getting financially attractive.