Solar power has begun to transform the world’s energy system

I recall that other power plants such as thermal power is still required to provide “inertia” for the whole system, as solar fluctuates a lot. The recent Spain-Portugal outage showed that there is not enough inertia in the system.

I don’t really understand inertia in power plants but I wonder if it helps to push nuclear as primary and solar as secondary?

The more likely future imo is different forms of dedicated inertia rather than inertia that you used to automatically get from old school power plants with big turbines. Both will coexist of course. Financial incentives for different support systems for electrical grids will continue to evolve in the foreseeable future.

This is mostly a matter of control systems engineering: inverters tend to be perfectly grid-following, but there's no reason why the phase angle can't be adjusted to provide "virtual inertia". Same for battery systems - an early market for these in the UK is getting paid for "fast frequency response". Every battery can be a virtual flywheel. https://www.modernpowersystems.com/analysis/batteries-for-fa...

Conversely, the Spain problem appears to have been a classic control systems problem of a slow undamped oscillation that gradually got out of hand.

(I believe the preliminary incident reports got published and discussed on HN, if someone would like to link that here?)

Nuclear may or may not have a role, but it's much slower to build than solar, so starting a plant now is going to face a very different landscape with a lot more solar in by the time it completes.

The best way of doing things changes as market prices for the various options change. At the moment we mostly have renewables, wind and solar backed up by natural gas powered plants that can increase and decrease power rapidly. As time goes on and batteries and solar get cheaper things will probably move more to those. Nuclear is good for constant power but expensive.

Thanks. One benefit about nuclear, maybe I’m overstretching a bit, is that it is a large system engineering project so hopefully it trains and retains many engineers and technicians. Maybe solar farm serves that purpose too? But somehow “nuclear” sounds more cool…

> The recent Spain-Portugal outage showed that there is not enough inertia in the system.

At the moment it showed nothing, because it's still under investigation. You might be referring to the FUD campaign that started the same day of the blackout.

But it is true that inertia is provided mainly by conventional power plants, and they are being removed from the grid. It is also true that, if finally the lack of inertia is confirmed as the cause of the blackouts, there are alternative ways to provide inertia in the system: synchronous condensers (https://en.wikipedia.org/wiki/Synchronous_condenser) like the one in Moneypoint (https://en.wikipedia.org/wiki/Moneypoint_power_station).

From my experience in construction sites as an electrician… It is a race to the bottom. Cheapest subcontractor gets the job. Nobody cares about any training. And there are no engineers at all in construction sites. Overseeing engineer is simply too expensive. Obviously it shouldn’t be that way.

a nuclear power plant is very expensive and takes a long time to build. they're also designed to deliver constant output (i don't know how fast they can de-/increase output), so if power prices get into negative territory due to overwhelming solar output, nuclear power plants might have to operate at a loss, making its product comparably expensive. there are environmental factors (need for water sources for cooling), political/nimbyism and fuel dependency from foreign powers. so nowadays you have trouble finding willing investors. also, due to low demand there are few nuclear plant building companies left.

I so much hope that we (the world) replace thermal plants (except geothermal) with nuclear ones. But yeah there is a lot of resistance and it is very expensive.

Is that a benefit or a cost? People these days have to train at their own expense, and construction trades are in something of a short supply.

I'm more thinking about the side of designing and implementing complex engineering systems instead of individual trades, but I'm just an armchair poster so don't know much.

There's a property called "learning rate", which roughly measures the extent to which doing some kind of project more makes it cheaper. Renewables have hugely benefited from this at every level, from manufacture to installation.

Nuclear, somehow, exhibits a negative learning rate: the more nuclear projects you do, the more expensive it gets. https://www.sciencedirect.com/science/article/abs/pii/S03014...

Grid inertia is the rotational kinetic energy in synchronous generators that stabilizes frequency during sudden load changes - modern solutions include grid-forming inverters, synchronous condensers, and virtual inertia systems that can provide this stability without requiring traditional thermal plants.

i too hope we soon replace all fossil fuel plants with alternatives, but i don't think it'll be nuclear, for the reasons given above.

there'll probably be an increase of solar and wind for many more years, as they're a safe bet - cheap, low maintenance and you don't need much skilled human labor to operate it.

additionally, battery storage will be become ever cheaper and more ubiquitous. together with traditional storage options, like water. we'll see how far that gets us.