Comment by gwright

I LOVE that site. The Achilles heel of it is that it doesn’t account for transmission costs, but that’s solvable by just picking a single point (ie no geographic diversity or transmission). Overall, it’s the perfect antidote for all the commonly repeated but wrong claims on the Internet (and this goes for everyone).

This is really interesting but I am not seeing how it gets to end price. It's saying around 54eur/mwh in the UK with the 2020 technology assumption.

I can see that cost for the solar/wind itself but seems very low for the masses of hydrogen (and associated round trip losses) that it's suggesting. I have read some estimates that it could at least double the price?

I think the assumption you need to use batteries alone for seasonal storage or that you need a pure zero emissions system is missing the point.

A system that has a gas turbine backup for that non-windy week of winter that happens every 5 years is something of substantial value. Use batteries for capital maximizing daily cycles, and leave coal and gas as "storage" for seasonal emergency cycles, this would be a major, major achievement for humanity.

Well in terms of the various capabilities the article highlighted

    * dark starting
    * capacity
    * grid stabilization

it sounds like the battery plant is successful. But the article itself says that the plant does not replace the "energy" component of the old coal power plant, which is why I asked the questions I asked. And it is the energy component that is critical for really retiring base load capacity provided by fossil fuel plants at grid level. Without the ability to retire the base load capacity you aren't really solving the problem. Costs rise dramatically (you now have two energy systems) and/or you have to accept less reliability (running out of power when wind/solar/hydro/battery are inadequate).

I think you are mis-interpreting my comment and being unfair in characterizing what I'm saying as "narrow minded" or "grasping at straws".

> The old coal generator provided three key values to Oahu, Keefe explained: energy (the bulk volume of electricity), capacity (the instantaneous delivery of power on command), and grid services (stabilizing functions for the grid, wonky but vital to keeping the lights on).

> The battery directly replaces the latter two: It matches the coal plant’s maximum power output (or “nameplate capacity,” in industry parlance), and it is programmed to deliver the necessary grid services that keep the grid operating in the right parameters.

It’s about 12 weeks in Germany:

https://iopscience.iop.org/article/10.1088/1748-9326/ac4dc8

> Do you have any links to those studies? Because the ones I've seen indicate the exact opposite. You only need 2-3 days of storage or so at most.

It depends very much on where you live. Famously, California can get to 100% renewable production with 3 hours of storage, because production is very stable, load peaks match production well and there is sufficient natural hydropower resources available.

In contrast, Finland would need about 3 months worth to hit 100% renewable. Because worst load peaks happen when production from both wind and solar can be zero for a prolonged period, and natural hydro output is limited at the same time. 3 months is absolutely not actually feasible, so there will always need to be some baseload from nuclear or fossil sources.

But 2-3 days of storage is still quite a lot. The recently started OL3 power plant had a total construction cost of ~11B€, making it one of the most expensive construction projects ever. It has a nameplate capacity of 1600MWe, assuming 95% capacity factor (it goes up when it's cold and down when it's warm), if you spent it's construction cost building grid-scale batteries, assuming the lowest cost of a completed battery project anywhere in the world, you'd get something like 27 hours of storage. So even if the primary production was free, if you need more than that, you'd be better off building the world's largest and most expensive nuclear power plant instead of batteries + renewables.

> Marc Z Jacobsen has some fairly detailed studies for going 100% renewables. He doesn't generally assume any improvements in technology, so his estimates are conservative. I don't remember seeing anything about seasonal storage.

He was a coauthor on a recent review article on 100% RE energy systems. One conclusion of the review article is that e-fuels are very useful, and that with e-fuels costs are similar to those of energy systems based on fossil fuels.

E-fuels (like hydrogen) inherently provide very long term storage.

https://ieeexplore.ieee.org/document/9837910

This report, which is often quoted,

https://www.eia.gov/analysis/studies/powerplants/capitalcost...

gives a crazy low cost for a solar + battery plant that assumes storage for an hour and a half which is certainly too little. When I split out their generation and storage numbers and put in the assumption that 12 hours of storage gets you through the night the price is getting in the same range as gas turbine power plants.

There's the seasonal problem too, the answer to that is some combination of building more solar capacity or adding huge amounts of storage. I'd estimate that the daily insolation varies by a factor of 2 or so in NY

https://www.solarenergylocal.com/states/new-york/new-york/

so you could build maybe twice the solar capacity and have enough generation in the winter. Judged that way the system cost is creeping in the direction of what nuclear energy costs, though you've got a lot of "free" electricity in the summer although that could be "free as in puppy". Hypothetically you could do something like desalinate seawater and pump it uphill into reservoirs but operating any kind of industrial factory intermittently is going to be murder for capital and operating costs. There is this idea

https://www.moderndescartes.com/essays/factobattery/

where you could smooth out diurnal variation in a "hydrogen economy" factory by overbuilding electrolyzers, but to take advantage of "free" summer electricity you might have to lay off all your workers half the year not to mention building surplus transmission infrastructure.

Of course it takes detailed modeling of supply and demand to get good cost estimates for renewable plus storage systems and one thing I find irksome about that EIA report is that it quotes one number for a solar energy plant which is just wrong because the exact same solar plant will product a lot more power in Nevada and it will in Wisconsin. Many people are quoting these numbers and not really aware that they are discrediting themselves and the renewable energy cause because quoting a number that doesn't depend on time and place just violates common sense.

Here is a study for two areas, Germany and California:

http://euanmearns.com/the-cost-of-wind-solar-power-batteries...

> so you'd need to have something like 10x solar if you wanted the overcapacity strategy to work, which also make things prohibitively expensive.

In the short-term, gas backup for such scenarios (which are relatively rare, and during which renewables will still operate at some non-100% fraction of the required energy) seems like it might be a reasonable option: we could probably get to (pulling numbers out of thin air) 95% renewable generation or something that way.

Longer term, we'll definitely need some kind of long-term storage though. Perhaps synthetic fuel driven by overcapacity renewables during peak generation times might be an option here?

Germany can do it with a combination of wind, solar, batteries, and hydrogen.

The green hydrogen is crucial, to deal with Dunkelflauten and to some extent seasonality. Germany has ample salt formations for cheap hydrogen storage. At the site I linked elsewhere in these comments, the solution for 24/7 power from RE is nearly doubled in Germany if green hydrogen is omitted.

Germany is suffering now from the decision to pay for the 2009-2012 solar builds using long term high rates. When that ends (2032?) the costs should come down a lot. Building out solar now should be much less expensive.

We don't know if 10x will be prohibitively expensive going forward. It can also enable new kinds of uses of electricity we don't have today, offsetting the cost of build-out.

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Seasonal is possible, but I'd imagine scaling it is tough.

https://en.wikipedia.org/wiki/Drake_Landing_Solar_Community

https://www.planete-energies.com/en/media/article/how-does-l...

There is almost always wind in Hawaii.

In late winter/early spring sometimes the trade winds get "funky" and there will be days where there is absolutely no wind at all and it is a little eerie.

What's the geothermal power potential in Hawaii? Seems like it would be a good source for it to me.

Not sure about calm (I feel like there's pretty much always some wind), but the rainy season brings lots of clouds. And even outside the rainy season there are days cloudy enough to impact solar generation.

Which is why I asked if the weather conditions changed the calculus in Hawaii. Great for Hawaii, but doesn't help in other locations.

The same is true of other types of energy production... like when France lost 50% of it's nuclear simultaneously...

https://www.france24.com/en/france/20220902-france-to-restar...

Ultimately every technology has some unplanned downtime, and there will always be a risk of too much not generating simultaneously.

The problem is that is non-tropical regions, in winter you get less sun and long periods (3 weeks is routine in European winter) with no winds so you need to be able to supply enough power for a very big amount of time.

Why do you think that can't be right?

Solar and wind generation themselves are seasonal and don't match the seasonal patterns of demand. So you need to time shift across seasons if you don't have the instantaneous (base load) capacity available all the time.

You might say, well, just build more windmills or solar farms. Doesn't help when it is dark and calm. Your "overbuild" is useless in that situation. So you need storage (or other base load generation, fossil or nuclear).

In this study, it is estimated that Germany and California both need about 25TWh of storage to time shift energy supplied by intermittent sources to other parts of the year. The study claims $5 trillion to purchase batteries to store that much energy.

http://euanmearns.com/the-cost-of-wind-solar-power-batteries...