The only way to exclude the market from the equation is for the state to have total control over the entire energy pipeline, from pulling natural gas out of the ground to the power plants to delivery.

You can't simply mandate that energy prices will be a certain amount if the power plants still have to buy natural gas and other power sources from the free market. If you tried, the power plants would simply shut down when it wasn't profitable according to the legislated rate, making the problem even worse.

If you tried to legislate that power plants or energy producers must sell energy at a fixed cost no matter what it costs them to produce and they can't shut down, they have to price that risk into their long-term model. You're now paying more for the same service just to make it worth someone else's while to take the risk.

The energy market at least provides a feedback loop to large, energy-consuming businesses. Large consumers of electricity like manufacturing facilities will simply decide to shut down when energy prices are too to be profitable, and wait for the cost to go down. You don't see this as a homeowner, but there are industries that adjust their schedules around energy pricing.