Do people use much energy during the day in winter though?
At higher latitudes, the sun doesn't shine nearly as long, and the days are often overcast for weeks on end. Your storage needs to smooth over weeks, not hours!
The cost of that storage, and the solar array, would be much higher than the nuclear plant.
You'd be surprised at how low grid-scale solar/wind plus storage costs have dropped, especially once taking into account full lifetime operating costs.
Optimally, you build an energy mix for the worst day of the year, not storing *electrical energy for the long term (other types like heat/pimped hydro may make sense at those timescales)
> Do people use much energy during the day in winter though?
Saskatchewanian here! Your use of the word "energy" here is critical. We use a ton of _energy_ non-stop through the winter. Looking through the last year worth of statements, my wife and I used 1,794 m^2 of natural gas in Feb 2022, and 59 m^2 of natural gas in June 2022. Conversely, we seem to average about 700-800 kWh of electricity every month, but last August we used 1,456 kWh and the most recent bill had 1,159 kWh (electric air conditioning).
We use a crap load of natural gas to heat our homes throughout the winter, and that basically drops to nil during the summer (only the hot water heater). Electricity varies less, but there are huge summer spikes.
What nuclear does, from my PoV, is give us not only a road out of burning coal (ick) for our base load electricity, but also makes electric-heat-conversion a more viable proposal. While the temperatures do get cold enough sometimes that a heat pump/HRV loses its effectiveness, getting to a point where we have a COP of 3-4 using the heat pump and backing it up with resistive heating is a huge win if the electricity powering those devices isn't coming from a coal-fired plant.
Typically the coldest days are near peak darkness with clear skies and no wind.
At higher latitudes, the sun doesn't shine nearly as long, and the days are often overcast for weeks on end. Your storage needs to smooth over weeks, not hours!
The cost of that storage, and the solar array, would be much higher than the nuclear plant.