[amalcon]

The problem with unrestricted spot pricing is that it's easy to end up with a surprise bill due to circumstances beyond your knowledge or control. E.g. the heating system fails in the apartment complex next door, so everyone plugs in space heaters. Your bill goes up also due to the increased demand. They can get insurance to cover this sort of eventuality -- can you?

I know two ways to fix this. First, obviously, you didn't say "unrestricted". There are various ways to restrict spot pricing to alleviate these issues, e.g. guarantee each home a particular amount at a fixed rate, and overages are at spot rates. Second, the "knowledge" angle can be attacked -- if you know that's happened, you can turn down your thermostat.

[nawitus]

In Nordpool the prices are set the day behind so there's no surprise bill. If the spot price goes up one actually should pay more, which incentives reducing electricity consumption.

I think your apartment complex example is not that realistic as it won't affect the spot price. Something more like a war will..