The keyword in Small Modular Reactor is Modular. 5mw is not "too small for actual usage." You can connect many of them together in one plant to produce however much power you want. Just like wind turbines, a typical design includes more than one.
Alongside a few MWt to shed into district heating, that seems pretty nice in a distributed grid context.
> Just like wind turbines, a typical design includes more than one.
Wind farms are a thing because location is an issue, and there’s a lot of nimby-ism, so if you can plop down turbines you plop down a bunch.
Though I guess nimby would also affect SMRs, location is way less of an issue, if you have space for a farm you might as well use a classical nuclear plant.
Plus the capacity factor of nukes is way higher than turbines. Assuming SMRs follow the nuclear norm you don’t need to overbuild to compensate.
Capacity factor of nukes is not so much more than of wind turbines, though if you have a bunch of nukes, it would be rare to have many of the nukes down at once other than for urgent retrofits. Steam turbines are down a lot, so nukes are always built with two or more.
But the main thing is that nukes cost far, far more than the wind farm that produces as much; or, a wind farm at the same price produces many times the power, with near zero lead time and possibly negative decommissioning cost. After their contribution to the grid gets large enough, you build out storage, which incrementally reduces the fraction of time you spend burning NG or, later, ammonia.
A farm of small nukes would cost quite a bit more to build than a big nuke of the same capacity, because all the systems are duplicated throughout. On the up side, the farm might be built incrementally with much less of the graft always attached to monster public works; you might save 75% vs a big nuke just on that basis. If you could get the first one going early, its revenue might help pay for subsequent units.
But whatever the heat source, anything with a steam turbine is just not competitive anymore. That is another reason why fusion is a dead end: it is just very hard to compete with zero opex.
It still wouldn't be economical in the short term due to construction, water, nutrients, etc. But it's something solar can't possibly provide because there's only so much sunlight per acre. Long term, we could stop trying to farm every square inch of arable land on the planet, of which we're already farming about half.
It'll still be cheaper, thus it will still be done.
Mark my words, we're giving nothing back to nature.
No, it won't. One problem with arable land (i.e., land that's really good for growing crops) is that it's also usually land where people really want to live. Non-arable land is places like deserts and tundra, and almost no one wants to live there, for obvious reasons. So farmers are in competition with developers (and eventually property buyers) for using the best land.
However, it is really good for growing certain crops, and that's why it's used for that, and also why America has historically had a huge advantage by being the "breadbasket for the world".
I assume there is a good answer to "why not" here; and it's one that's probably related to the "why" for SMR.
You also have packing issues: cylindrical cells are basically optimal, because they distribute any internal pressure equally. If you play with something like the prismatic Prius batteries, then despite being larger you have far less options to pack them because you need to counter-pressure them horizontally or they swell and then fail.
Charging 20 teslas at maximum charge rate. Or 1k houses, provided it's general use and not electric heating. 5MW is 43.8GWh/year or an average annual power consumption of 8-12k people in the west (per capita consumption - so includes industry use). Accounting for peak vs average this is likely enough for 3-5k people.
Obviously, peak load vs average load is very important so I wouldn’t expect the energy to go that far, but connected to a big battery… probably, right?
One of the major reasons for wind farms rather than isolated turbines is the economic and environmental cost of grid connections and roads needed for installation and maintenance.
The goal is for them to be autonomous for this reason: install it at some industrial site without any nuclear expertise. Have it shipped in fueled, and then shipped out to maintain or refuel.
These are absolutely the future.
Engineering With Rosie has a truly excellent video that analyzes many of the scaling laws: https://www.youtube.com/watch?v=Ze-zaW3au9Q
GE gas turbines for example are 35 to 570 MW. https://www.ge.com/gas-power. They have stopped making smaller ones. There probably are even 100 kW gas turbines made by some companies but that's not used for major power generation (maybe as an airplane APU).
You probably won't have these small reactors in towns of 5000 people run by some local operators, because nuclear technology requires so much special training and is so risky because of the potential radiation hazard.
You might have 20 in one powerplant in a city, to provide 100 MW, as part of the energy mix (it's always good to have multiple sources).
There is a certain threshold for nuclear technology. It's not the same as a diesel generator that anyone can put in their back yard. The risks are too high.
Yet, the current reactors like the Olkiluoto 3 EPR in Finland at 1600 MW electrical power are too big and unwieldy and risky. When it turns on or off, it causes some problems to the rest of the grid. One reason for such a huge plant was there was a legal process to provide permission for one reactor. So if you can only build one, of course you try to make it as big as possible. This doesn't make sense from engineering sense - it probably would make more sense to build something like power plants of 4x400 MW reactors (the seventies plants are 2x400 MW reactors).
So all in all, probably more optimal size for "small" reactors would be 20 to 200 MW. They're big enough that the radiation protection doesn't eat all the budget, yet they're small enough that you get to build many and can build a production line.