You don’t know that. There have been studies that have founder lower total system costs with renewables. See studies by Marc Z Jacobsen et. al. for instance.
I know of one study that found fairly low costs with lots of nuclear. But it also assumed continued fossil fuel extraction and a whole lot of CCS, which is not a sustainable solution.
The problem with many analysis that show favourable outcome with nuclear is that they only look at decarbonising electricity. If we look at the big picture, and what’s required to decarbonise everything, you find that we gain a huge amount of flexible load. EVs can charge when electricity is cheap, or even feed energy back into the grid. Switching industry to electricity for heat lets us make heat batteries which can store enormous amount of energy for a very long time. In fact, it may be the only economical way to do it, since they’d end up using a lot of free excess energy from renewables. If they had to use nuclear they’d have to pay the full price of electricity. There’s some proposals to use the heat from nuclear power plants but that has limited applications. You can’t collocate all industry next to nuclear power plants.
There’s a company working on an induction cooktop with integrated batteries, because it may be the only way to replace gas cooktops in some places, as induction ones require a lot of peak power. It’s expensive to upgrade capacity. But if the batteries charge when electricity comes a cheap it’s not an issue. And an induction cooktop has all the components needed for an inverter so it can double as battery backup and save power on your electricity bill.
There are a million solutions like this already in the market or in late stage development. A future where we solve carbon emissions is necessarily a future where the load balancing problem of renewables is solved. Betting that we’ll need nuclear is equivalent with betting that we can’t sustainably solve global climate change (CCS is not a real solution in my book)
