Canada

Nuclear power is vital if we’re going to get rid of coal and gas. Nuclear provides adjustable (can be easily scaled up and down just by moving the control rods) base load power as well as grid forming (maintains steady 60Hz AC all the time).

Wind and solar do not supply base load power. Their power output varies with the sun or wind as well as the seasons. It’s important to note that power grids have zero storage capacity of their own. If there is excess power generation then power plants must be either dialled down or disconnected from the grid in order to prevent voltages from going too high (and damaging equipment).

On the other hand, if there’s not enough power then additional capacity must be brought online. Typically this is done with natural gas “peaker” plants (because natural gas is usually too expensive for base load power) but it can also be done (up to capacity) with nuclear plant control rods, albeit not quickly (in response to unexpected demand) so it’s generally used to vary power output throughout the day in order to match the expected supply and demand curve of the grid.

It’s been proposed that we build grid energy storage using batteries or pumped water for hydro but I don’t know of any realistic large scale proposals due to the large costs involved. Of course, grid energy storage won’t help if it’s already been charged to full capacity and there is still excess generation. It also doesn’t help if storage is depleted and there is insufficient production to meet demand.

The other issue I mentioned earlier is grid forming (maintaining steady 60Hz without any phase shifting). The advantage of big turbines (nuclear, coal, gas, hydro) is that they are large and very heavy spinning objects so they have tremendous momentum which means they don’t drift and can be maintained at a steady exact multiple of 60RPM (usually 1800RPM or 3600RPM) which makes it easy to produce stable 60Hz electrical output without undesired phase shifting.

Wind and solar cannot do this. These generators use electronics to produce DC power and then an inverter to convert DC to 60Hz AC. The challenge here is that the inverter output needs to be synchronized to the grid since out-of-phase power generation fights against the AC power already present on the grid.

But then what happens if the only generators on the grid are wind and solar with inverters? They all try to synchronize with each other and you get constant oscillating phase shifts! It creates total havoc on the grid. This aspect to power generation is very poorly understood and appreciated by the general public but it’s absolutely vital to avoid the problem.