Comment by nawitus

The reasoning is that it incentives electricity producers to offer max amount of electricity at low prices without speculating how to maximize profit (as their sell offer will practically speaking have zero effect on the spot price). Nuclear plants, wind power, solar can just offer to sell at everything at around 0c/kWh.

It's claimed that another type of market would cause companies to speculate with their sell offers and thus generate less electricity. It would be interesting to see how this kind of market would work in reality, though.