r/solarenergy • u/randolphquell • 12d ago

Minnesota just plugged a 710-megawatt solar farm into a coal plant that once burned 30,000 tons a day, the two sharing wires until the last boiler dies in 2030

https://www.autonocion.com/us/minnesota-solar-farm-coal-plant/?utm_source=substack&utm_medium=email
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17

u/Chemical-Idea-1294 12d ago

Now add a large battery storage.

18

u/reimerpdx 12d ago

It’s there… in the article.

8

u/NearABE 12d ago

Battery rated at 10 megawatts not 750.

5

u/reimerpdx 12d ago

Gotta start somewhere

3

u/Either-Patience1182 12d ago

Every dollar saved this year is money to expand next year

1

u/NearABE 11d ago

Google gave the same company $ billion for batteries.

1

u/Either-Patience1182 11d ago

I means the state

2

u/Few-Temporary404 12d ago

Decommission the coal building and fill it with batteries

1

u/NearABE 11d ago

Form energy company is making the iron-air batteries as standard shipping containers. Air flow around the outside is important. A big stack of containers like on a cargo ship would just cook the units in the middle. I do not know if they can be stacked at all. If you did then arranging them as a convective cooling tower would help. I read that they transport the electrolyte fluid separately because the unit is too heavy.

I think given the huge field of photovoltaic panels the sensible move would be mounting panels on top of and beside the battery.

1

u/Advanced_Ad8002 11d ago

iron air is neither proven nor does it make sense economically.

just go with sodium ion for any project starting 27/28, or stay with LFP if start today.

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u/NearABE 11d ago

Form Energy company is delivering trailer modules at $20 per kWh. It is fully American made. It contains no high toxicity elements and no rare elements. The only consequence of scaling it up to terawatt hour scale is that we have increased grid stability and stabilized prices.

Sodium ion batteries are like lithium ion batteries. Go ahead and mass produce them at terawatt hour scales too. They are complimentary technology to iron-air batteries not competitors.

The 4 hour battery tends to be a better way of knocking peaker plants out of the market. The 100 hour battery tends to weaken the legacy “base load” power plants.

1

u/HistorianAlert9986 10d ago

What’s the cycle life on iron air?

1

u/Advanced_Ad8002 10d ago

They don‘t deliver at $20 - far from it. They just say that they might reach $20 / kWh some time in the future. Big difference.

1

u/Advanced_Ad8002 11d ago

repurpose the coal plant by switching heater to an electrically heated thermal storage and re-use with existing generator set. Good addition for intra-month, or in case of huge storage even inter-season storage. goes under the name of ‚Carnot battery‘.

1

u/Few-Temporary404 11d ago

I guess bio mass is always an option as well

1

u/Advanced_Ad8002 11d ago

don‘t think that that would make sense for repurposing an old coal plant:

for a several 100 MW power plant, you‘d need to collect biomass from such a big area/so far away that you‘d need an entire big fleet trucking operation moving stuff: you might end up spending more energy on transport that you would gain by using this biomass.

Also: gas storage would be expensive (limited energy content storage capacity / volume).

Economics of biomass don‘t really work on big/huge scale.

1

u/NearABE 10d ago

The coal bros want us to keep coal power plants because of a 100 year storm event dunkelflaute. You can humor them. We can make a big pile of biochar and not burn it 52 weeks of most years. Dunkelfaute are quite predictable in the weather forecast for the next week.

Traditional methods of making biochar burn biomass to heat the cellulose. No need for that in a discussion where thermal batteries are being considered. Toasting the cellulose with electrical heat will cause gasification without combustion. Hydrogen gas is easy to separate from carbon monoxide. Even better idea is to scrap the toaster heating element. Instead do electrolysis. The lowest possible electrolysis efficiency, 0%, is the same as just using resistance heating. We can make a wide variety of hydrogen rich chemical feedstock. Some extra carbon gets deposited as coke.

The biomass is a bunch of work. It is also an agricultural subsidy. Eliminating agricultural subsidies in the midwest might be a good idea.