Discussions about this topic tend to get a bit hand wavy very quickly and few people seem to be able to apply any rational system thinking to the whole debate. That's true for proponents and opponents. I've been reading through, and occasionally commenting on threads on this topic on hacker news for a while now. So, I've seen all the arguments. From both sides. There are usually a few bright people commenting but a lot of others seem to lose the ability to do math or conveniently reason under some closed world assumptions. Or just dismiss the notion of math entirely. Basically, anyone focusing on a single technology as a holy grail tpye solution is probably barking up the wrong tree. The notion of system thinking is having a mix of everything that's already being done and evolving that in a direction where less of it is going to involve fossil fuels.

Let's consider a few technologies that already exist (in addition to wind and solar) and work at scale or can be made to work at scale that can be freely combined with wind and solar.

- Pumped hydro. As of yet one of the most widely used energy storage on grids in e.g. the US. There's about 22 GW and about 0.5TWH of it on the grid. A lot of it was, ironically, installed decades ago when nuclear plants started coming online and something had to be done with the massive amounts of energy that they produced. It's relatively expensive and it can't be done everywhere. But it's proven technology and its there already. There are lots of smaller scale trials with all sorts of gravity batteries. Not all of them practical of course. Though using e.g. mine shafts seems like it should work.

- Cables. We can use cables to move power around by the GW. It's an old technology. Has been around for as long as we've had electricity. This can be done over thousands of kilometers using modern technology. Examples: cables are already running between Norway, Germany, and the UK and more are being planned between e.g. Morocco and the UK, Australia and Singapore. A single cable can provide roughly the capacity of a largish nuclear reactor. I think the Moroccon cables are going to be 1.8GW each for example. The current plan is to have four of those. Cables aren't cheap. But they are probably comparable to largish nuclear plants in terms of the amount of power they can move and in cost. And they last for a very long time once you have them. Great argument if you hear people make the point that the wind doesn't blow all the time and the sun doesn't come out in the winter. True locally but cables fix the locality problem. Cloudy UK can rely on sunny Morocco. Wind starved central Europe can use off shore wind.

- Geothermal. There are lots of places where people are already exploiting geothermal energy. It seems more interesting to use for heating than for electricity but both are a thing. Digging deep for higher temperature gradients is expensive. But there also are a few newer projects involving heat pumps that don't require that.

- Grid batteries. These are currently being deployed by the gwh and probably soon twh. This is a rapidly growing market. Mostly this seems to be with relatively expensive batteries that provide hours, not weeks of storage. But interest in much cheaper but more voluminous battery chemistries that might be used for longer term storage is picking up as well. Too early to pick any winners here but there's simply too much of this stuff going on to dismiss it.

- Domestic batteries and EV batteries. Love them or hate them, these are being mass produced and installed as well. Tens of millions of EVs are going to require batteries to be produced by the twh per year and that's going to be a reality within a decade. The volume of batteries on the road is soon going to exceed the yearly energy consumption in a lot of places. That would be a problem if those vehicles would be moving 100% of the time. Which of course they don't. Domestic batteries are not far behind this but those too are starting to add up as their cost is going down. So despite there being so much battery on the road, we may not actually have much of a case for vehicle to grid technology to actually tap into that reserve. Because we'll have plenty of other batteries permanently connected to the grid. Either way, hard to dismiss any storage that is going to measured in many twh.

None of thesse things of course are free and relying on them exclusively is not a solution. Especially considering that some of these are actually quite expensive. But the reality is we are already doing those at gw scale and soon at tw scale. And it's all happening on the same interconnected grid.

Cost is not a constant and there's a trend for mass production to get cost down for a lot of these things. This is true for nuclear as well. At least hypothetically because our current nuclear production capacity is too low to show any signs of a learning effect so far (if anything it seems to have gotten more expensive over time). But hypothetically cost would come down if we did more of it.

But the simple fact is that by virtue of people installing solar and wind at break neck speed there's going to be no shortage of vast amounts of excess power peaks that can be moved around and stored. Which does raise the question what the point is of focusing on expensive nuclear projects in a lot of places.

System thinking is the notion that we can use all of these solutions, and more, to create a highly resilient and robust, interconnected grid. Nuclear can certainly play a role in that and it looks like it will. But it's probably going to be a much smaller one than some people would like us to think.