Solar battery backed is under $100/MWh (wind even cheaper), and those costs will decline rapidly as battery manufacturing scales up.
Nuclear will never get cheaper, not to mention the rapidly increasing decommissioning costs everyone is keeping off the books. Batteries are mostly non toxic and easily recycled.
A backup battery for the 10-day wind lull from Dec 5th to Dec 15th in the Pacific Northwest would cost $90B and be a football field 100 stories high. Then it'd have to be replaced every 20 years. The footprint of something like that from a land, mining, and carbon standpoint is not trivial.
That doesn't sound quite right. Nuclear is very energy dense and has very low footprints in terms of land, fuel, mining, pollution, waste, and everything else except capital cost. I hope we can figure out how to build them cheaper.
Acres per Megawatt Produced for different energy sources [1]:
Coal 12.21
Natural Gas 12.41
Nuclear 12.71
Solar 43.50
Wind 70.64
Hydro 315.22
Maybe today, but with demand (and thus potential profit) for grid-scale storage increasing we see a lot of promisimg research in that area. Li-Ion is engineered for completely different tradeoffs, so there's massive room for improvement.
The 4 GWe wind farms have an average capacity factor of 35% so over ten days that's 336 GWh or 4.8 million Teslas, and that's just for the fraction of electric generation that's wind in the PNW. Scale that up to full electricity and then full energy and you're looking at a pretty serious challenge. Batteries are generally not what people consider for grid-scale power. The 100% renewable Stanford superstar, Jacobsen (who's suing his scientific critics), doesn't even use batteries in his scenarios (he uses pumped hydro and hydrogen instead).
The problem with battery backed is getting longer storage; The UK government has just reduced the subsidy for storage technologies that can't keep it going for a few hours; See https://www.emrdeliverybody.com/Lists/Latest%20News/Attachme... for the full assesment of how they came up with that.
Nuclear will never get cheaper, not to mention the rapidly increasing decommissioning costs everyone is keeping off the books. Batteries are mostly non toxic and easily recycled.