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I've read that 6 hour battery storage in a locale with wind+sun covers close to 100% of non-corner-case demand. If WS is 2¢ a kWh and battery is 10¢ a kWh** the weighted wholesale price is 4¢ a kWh.
Since that scenario is available today and will only improve in the future, I don't think battery storage should be pigeon holed as a curtailment solution. Not that I really understand what 'avoiding curtailment' means in this context, since one would plan for clean energy production in excess of immediate demand to use later. But maybe I'm just tilting at a semantic proposition without a practical difference. One thing for sure though, the notion that that we should overbuild cheap WS to partly cover the generation lows has never made sense to me as an isolated idea.
** 0.9 cycles a day for 12 years, $400 a kWh installed
If the batteries are being used 'appropriately' the marginal cost of energy should be 0 or < 0. If the RE you're using to charge the battery could have displaced ~11kWh of NG at the time it was used to charge the battery and all you're doing with the battery is displacing 10kWh of NG later.... what was the point? You just spent ~$200/kWh on a battery to reduce 10kWh of NG at one time instead of 11kWh at another time.
The energy you use to charge the battery NEEDS to be wind or solar that would have been wasted because supply exceeded demand. You need to take 10kWh of RE that would have displaced ~0kWh of NG because as much demand as RE would meet was already being met.
This is similar to the oversized array question. Do you invest in more panels or a bigger inverter? The answer changes as panels get cheaper in relation to the inverter. Does it make more sense to invest in batteries or more solar and wind. As renewables keep getting cheaper even faster than the cost of batteries generally the answer is more solar and wind... even if ~10% of your new solar and wind is 'thrown out' because there just isn't enough demand when it's produced.
The energy you use to charge the battery NEEDS to be wind or solar that would have been wasted because supply exceeded demand.
There has to be some amount of batteries with solar/wind, otherwise, you'll be more reliant on NG.
My point is that if done poorly it's very easy to INCREASE reliance on NG by adding batteries. Maybe not in terms of capacity but energy. Sure... maybe a large battery bank might allow the retirement of 1GW of gas capacity. But that's a meaningless victory if the capital invested in that battery could have been used to reduce overall NG used more with an investment in renewables. From an emissions perspective if the choice is between investing $1B in storage so you can retire a 1GW gas plant OR.... KEEP the gas plant, skip the battery and produce another ~4TWh/yr of wind. I vote keep the gas plant and use less gas with more wind. What's the point of displacing 10kWh of NG later with a battery if you can just displace ~11kWh now?
I couldn't care less how many GW of gas turbines we have... so long as we keep dropping the GWh/yr.
This is spot on and touches on an interesting topic - the concept of "throwing away" solar/wind when they are overproducing is often worded like that's a bad thing.As renewables keep getting cheaper even faster than the cost of batteries generally the answer is more solar and wind... even if ~10% of your new solar and wind is 'thrown out' because there just isn't enough demand when it's produced.
Solar farm operators don't care about how much NG is displaced, they care about how much they earn displacing it.If the batteries are being used 'appropriately' the marginal cost of energy should be 0 or < 0. If the RE you're using to charge the battery could have displaced ~11kWh of NG at the time it was used to charge the battery and all you're doing with the battery is displacing 10kWh of NG later.... what was the point? You just spent ~$200/kWh on a battery to reduce 10kWh of NG at one time instead of 11kWh at another time.
The energy you use to charge the battery NEEDS to be wind or solar that would have been wasted because supply exceeded demand. You need to take 10kWh of RE that would have displaced ~0kWh of NG because as much demand as RE would meet was already being met.
This is similar to the oversized array question. Do you invest in more panels or a bigger inverter? The answer changes as panels get cheaper in relation to the inverter. Does it make more sense to invest in batteries or more solar and wind. As renewables keep getting cheaper even faster than the cost of batteries generally the answer is more solar and wind... even if ~10% of your new solar and wind is 'thrown out' because there just isn't enough demand when it's produced.
My point is that if done poorly it's very easy to INCREASE reliance on NG by adding batteries.
"rational" ^I don't see that happening, except during transitions where tariff rules lag the market where WS is cheaper than NG. Delivered NG to the utility would have to cost under 1¢ a kWh (30¢ a therm) for that scenario to have any chance of existing in a rational market
I don't see that happening, except during transitions where tariff rules lag the market where WS is cheaper than NG.
It would have to because of physics. The round trip efficiency of a battery isn't 100%. It's ~90%. So if you're not using curtailed RE you can either displace 10kWh of NG now or use a battery to displace 9kWh later.
Energy storage is considered a green technology. But it actually increases carbon emissions.
Only for coal vs Ng.It would have to because of physics. The round trip efficiency of a battery isn't 100%. It's ~90%. So if you're not using curtailed RE you can either displace 10kWh of NG now or use a battery to displace 9kWh later.
Energy storage is considered a green technology. But it actually increases carbon emissions.
....
Mid-day energy will get very cheap in the spring and fall thanks to abundant and cheap solar PV energy. This is a good thing. With the proper retail pricing signals, consumers will shift demand to take advantage of it to some degree.
We should be encouraging people to charge their EVs from 9-4 PM - in California when the grid is the cleanest and solar/wind is most likely to be curtailed. But instead most utilities incentivize charging from 12 - 6 AM - when emissions are fairly high.
I thought this was interesting, from South Australia (formerly known as the land of expensive electricity):
TOU plans offered to consumers. 1 AUD = 0.78 USD
Notice how off-peak is a fair description of most of the PV curve ? That is not by accident. Wholesale off-peak futures price is 3.8 AU ¢ per kWh.
- Off-Peak = 10am – 3pm
- Shoulder = 1am – 6am
- Peak = 6am – 10am and 3pm – 1am
SA today is the near future of California where TOU hours are concerned.
That article, written in 2018, may still be true today somewhat, but given the scale of grid-scale storage and renewables then, it's not surprising.It would have to because of physics. The round trip efficiency of a battery isn't 100%. It's ~90%. So if you're not using curtailed RE you can either displace 10kWh of NG now or use a battery to displace 9kWh later.
Energy storage is considered a green technology. But it actually increases carbon emissions.