To be fair 10 hours is either a pretty old or pretty massive unit. 2 hours might be a little more reflective of modern gas turbines. Especially combined cycles. But depending on how big the peak is, you need every available unit, both old and new.

Ultimately the issue is it’s very hard to meet that peak when all of your gas units have to go from 0 to 100% output. Much easier (and more reliable) to take them from 10% to 100%. Which is what grid operators do currently.

Yea an affordable battery in every home would be a slam dunk. This is kinda already happening with vehicle2grid (v2g) electric car protocols. But not everyone has an EV yet. And operators are still working out the kinks using this in the grid.

Plus the lithium batteries in cars have their own supply/recycling issues.

Gravity energy storage doesn’t scale well. I’ve replied to other comments with more detail on this.

There are more feasible energy storage technologies out there, but these are super cutting edge and are not ready for grid-level deployment yet.

The future of grid level energy storage is almost certainly not going to be gravity based. At least not on a large scale.

You can’t have 100% of load be renewable/solar and have gas units online on top of that. That’s over generation. You have to match the supply exactly with the demand. If you mismatch, you destabilize the grid. Undersupply causes blackouts, oversupply melts power lines.

If a unit takes 10 hours to start, solar hours are from 6am to 6pm, and peak load is at 7pm with 0% solar; when do you recommend we start this unit? At the minimum, we’d have to order it on at 7am. Units have to run at a minimum load, let’s say 100MW for this unit. So now you can’t 100% solar from 7am to 6pm, you have to leave 100MW of room for this base loaded unit.

This doesn’t even factor in regulatory requirements like flex, spinning reserve, and other balancing and reliability requirements. Grids are required to have emergency units available at an instant to prevent mass destabilization if parts of the grid fail.

Piggybacking on your grid stability point, another issue I don’t see getting addressed here is ramp rate.

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?

A/Cs are still running while the sun is setting, the outside air is still hot. People are also getting home from work, and turning on their A/Cs to cool off the house, flipping on their lights, turning on the oven, etc.

Most grids have their peak power usage after solar has completely dropped off.

The issue then becomes: how can we serve that load? And you could say “just turn on some gas-fired units, at least most of the day was 100% renewable.”

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.

Grid operators have to leave their gas units online, running as low as they can, while the sun is out. So that when the peak hits, they can ramp up their grid to peak output, without any help from solar.

There are definitely some interesting solutions to this problem, energy storage, load shifting, and energy efficiency, but these are still in development.

People expect the lights to turn on when they flip the switch, and wouldn’t be very happy if that wasn’t the case. Grid operators are unable to provide that currently without dispatchable units.

I really like your response. Right behind you about energy storage.

Whoever cracks that nut is an instant billionaire in my opinion. The first cheap, effective, and practical storage technology is going to change the world. But we’re not there just yet.

I’m curious on your statement about nuclear. While I do think nuclear is a great energy source, I’m not sure I agree on the on-demand part.

Our current nuclear plants take hours or even days to start up and wouldn’t provide enough reactivity for a highly renewable grid. Are you referring to a future Small Modular Reactor technology? One with a significantly faster startup and ramp rate?

There have been proposals for technology like this. Putting a motor above an abandoned mineshaft and suspending a weight. Charged by raising the weight, discharges by lowering against a load.

The issues is the capacity ends up being pretty tiny, not really at a grid level.

You’d need a TON of motors to get to something a grid could actually use to stabilize, and by then the economics don’t work out. Let alone the actual space requirements of that many motors

Additionally, a lot of the advantages of batteries come from local storage, where you don’t need to transmit the energy long distances anymore, and these “natural” batteries tend to take up a lot of space.

A better and more accessible form of “natural” energy storage are already in most homes. Heat pump water heaters in homes could do things like make the water extra hot during solar hours, when power is cheap, so they can make it until the next morning without turning back on.

Or with better building envelopes (insulation) we could run more cooling during solar, maybe even make a ton of ice. Then later in the day, when solar drops and the grid load peaks, you can still cool the building with ice.

I spun up a MQTT/Aedes/MongoDB stack on my network recently for some ESP32 sensors.

Fantastic protocol and super easy to work with!

I like nuclear and all, but I don’t think nuclear can fill the same spot as peaker plants. Nuclear usually fills the base load needs on the grid. I don’t believe there’s nuclear with ramp rates capable of competing with a peaking gas turbine.

Energy storage does fill this gap usually. My ideal grid would be a semi-flexible nuclear baseload (+ some ancillary services), renewable “mid-load,” and energy storage peaking (+frequency response, etc.).

Yea my Adblock Home (pihole alternative) blocks the ads on my Roku home screen. Now it’s just a big blank box.

Hawaiian Electric’s modeling suggests it can reduce curtailment of renewables by an estimated 69% for the first five years thanks to Kapol Energy Storage, allowing surplus clean electricity that would otherwise waste to get onto the grid.