oh no! think of the stock market!

The original commenter's (OC's) point has nothing to do with renewables' reliability.

It is entirely to do with generation vs demand. Grid operators could ask other generators like coal, nuclear, hydro, etc. plants to curtail so inverter-based renewables can export power, but that's not likely because those producers can't ramp generation up and down as easily.

Grid stability is a problem when you have overcrowding of generation without enough demand on given feeders. This is moreso an issue with the utilities anyways and how they plan their transmission and substation upgrades.

What options do we have to stabilize a renewable energy system and make it long term viable?

If we install enough solar where 100% of our daytime load is served by solar, that’s great. But what about when the solar starts to drop off later in the day?

Store the surprus of energy from the solar panels and use that as a buffer with batteries or gravity

But some gas units take literal hours to turn on. And if you’re 100% renewable during the day, you can’t have those gas units already online.

Why not? Just time it and start it hours before, wind energy could help in that too

One solution to what you're describing is to expand the grid. If your grid stretches half the planet, when the East starts to experience night, the West still experiences day and can ship electricity from renewables to the East to make up for their self curtailment. The same goes for wind where if one location on the planet doesn't experience wind, odds are another location does and the power can be shuffled around.

Another option is to build out more battery storage such that any clipped energy from solar or wind - that is, the energy that can be generated from your solar or wind resource but that can't be exported because it would overload your inverters or transformers or exceed your PPA agreement with your utility - is stored and can be exported for 2-4 hours as the sun goes down or wind dies out.

Not a lot of renewables sites are colocated with battery storage, but more and more are.

I’m adjacent to this problem, so I have a little context, but am not an expert at all.

To my knowledge, we don’t have granular control over panels. So we can shut off legs of a plant, but that’s a lot of power to be moving all at once.

Instead, prices are set to encourage commercial customers to intake more power incrementally. This has a smoother result on the grid, less chance of destabilizing.

A customer like a data center could wait to perform defragmentation or a backup or something until the price of power hits a cheap or negative number.

I'm in solar/BESS, and I mean more and more DER sites are making use of string inverters which break out arrays into greater chunks than with central inverters. With those, you have more granularity of control where you can drop entire blocks/strings at a time to fall to your curtailed export rate.

You might ask yourself though why DERs can't just ramp inverter outputs up or down to match curtailment automatically across a whole site. You can absolutely do that, but what happens is your solar or wind resource stays high on the DC or low frequency (LF) AC side, respectively, while power frequency AC is low on the other side of the inverters. This is referred to as DC:AC ratio in the biz, and the higher that ratio, the more losses your inverters experience and less efficient they are. This also puts a huge strain on your inverters and can lessen their operational lifetime.

But really, DERs tie into the grid at distribution level and so they don't fall under the regulations of FERC & NERC (at least in North America). This means that smaller producers don't have the same requirements for control as do utility-scale players, so the incentive to control these string inverters at that granular level isn't there. It's much easier to just trip the main breaker and wait until the utility gives you the go ahead to turn back on.

I suspect that at lot of producers may want to look into greater control capabilities in the future, but this also depends on inverter OEMs too allowing that control.

If you’re spending billions to build a solar plant that has to turn off all the time during peak hours then you’re wasting your money. That seems like a fundamental issue to me, not a non-issue.

Ok, but what do you do when you're short of power at night? Keep in mind to turn on conventional power stations it's expensive & time consuming. Once they startup they need to stay on for a long while to be efficient & cheap.

The real solution is to store excess power in batteries. Lithium ion is too expensive to scale, Sodium ion batteries are economically & capacity viable AFAIK.

You can do more with them too actually. You can ramp down the AC power production incrementally to meet curtailment requirements, in theory. When you do that though you subject your inverters to greater strain/losses and less efficiency which shortens your lifetime.

If inverter-based producers in solar, wind, and/or BESS want their sites to last for 30-40 years so that ROI is achieved via operation, then it is in their interest to protect their equipment and operate as much as possible at rated conditions or de-energized conditions.

You might think that it would make sense to have more of a slider control between ON and OFF to save everyone, from producers to grids to consumers, but my guess from being in the industry is that grids don't really supply incentives for that kind of operation. If they did, maybe you'd see more variable control at utility- and community-scale levels.