It’s still not earning you money to spend electricity because you still have to pay the transfer fee which is around 6 cents / kWh but it’s pretty damn cheap nevertheless, mostly because of the excess in wind energy.
Last winter because of a mistake it dropped down to negative 50 cents / kWh for few hours, averaging negative 20 cents for the entire day. People were literally earning money by spending electricity. Some were running electric heaters outside in the middle of the winter.
The trouble with that kind of variation is that the economics of nuclear don’t make much sense. Nuclear is a large up front investment with (relatively) low marginal cost. If it’s running at a low level for half the year, then it can’t make back that huge initial investment in its expected lifetime.
We are currently charging very low overnight rates because we need to increase night time load on nuclear. With solar and wind being cheaper, grid operators are going to want to drive consumers to daytime consumption wherever possible. Night time rates are going to naturally increase, and I would expect artificial incentives on top of that to drive as much consumption as possible to the day, especially to clear, windy days.
The alternatives to nuclear are pumped storage, (which isn’t sufficiently scalable); traditional baseload generation (which is significantly more expensive); and various forms of peaker plants (which are much more expensive).
Basically, overnight and winter rates are going to rise to wherever nuclear needs them to be to remain profitable, because every other option has either limited feasibility, or higher costs.
You left out a large number of storage options. There’s plenty out there. Not every one is going to work for everything, but there’s almost always something that’s going to work.
Storage is important, yes, but it’s mostly a pipe dream. Few grid scale storage options are sufficiently scalable, and all storage is inherently inefficient.
We have a steel mill. We currently run it on nuclear power, overnight, during off-peak hours. If we want to switch it from nuclear to solar, do we continue to operate it at night off of pumped storage and batteries? Or do we move it to daytime operations? The former is “supply shaping”: adjusting our production to meet demand. The latter is “demand shaping”: adjusting our consumption to meet available supply. That’s the kind of thing we need to focus on.
At home, the single most important thing we need is mixing valves on our hot water tanks. These add cold water as needed to maintain a constant output temperature. This allows a variable, smart thermostat on the tank, that will superheat water when power is cheap, and let it fall when power is expensive. When solar excesses push rates too low, all of our water heaters start kicking on, sucking up cheap power during the day, and holding it through our night and morning showers.
