3 ms·

It also irks me that GW is used as a "capacity" figure, meaning "production capacity" or rate of discharge, when a battery's capacity is actually its stored ene

It also irks me that GW is used as a "capacity" figure, meaning "production capacity" or rate of discharge, when a battery's capacity is actually its stored energy (measured in GWh). Here are more details: https://www.eia.gov/analysis/studies/electricity/batterystorage/ https://www.eia.gov/analysis/studies/electricity/batterystor... Looks like in 2019 they added about 400 MWh and they provide 150 MW. In the "Full report" PDF, I see they are overwhelmingly (93%) Li-ion, which would be about 3.7V, so the capacity translates to ~108MAh and the current to ~40.5MA, giving you a C-use average of 0.375. Edit: I just realized I could have skipped conversion to amps, since the voltage simplifies in the fraction. I find it strange that Li-Ion is used, given that lead-acid can be much cheaper. Perhaps lead is not so environmentally friendly?

LinuxBender 5y ago
Perhaps lead is not so environmentally friendly? Here [1] are some of the reasons li-ion is currently preferred. This will change with time. I am holding out for the 3D printed solid state batteries which are not mentioned on that page but soon to be in mass production. [1] - https://news.energysage.com/lithium-ion-vs-lead-acid-batteries/ https://news.energysage.com/lithium-ion-vs-lead-acid-batteri...
jseutter 5y ago
Li-Ion has dropped in price to the point where it is cheaper than lead-acid. To come up with a realistic lifetime cost you have to factor in: - Cycle count (lead-acid ~500, li-ion 1000-3000) - Usable capacity (lead-acid 50%, li-ion 80%) - purchase cost (lead-acid $n, li-ion > $n) I'm about to over-generalize, but to get good lifetime out of your batteries, you only discharge lead-acid to 50% of its rated capacity, whereas li-ion has good cycle life working between 10-90% state of charge. You have to buy more lead-acid than you do li-ion to get the same usable storage. Then, your lead-acid batteries will degrade significantly after 500 charge-discharge cycles. The li-ion batteries will tolerate 2-6 times more cycles before significant capacity loss. Environmental friendliness is sort of a wash. Lead-acid is more toxic, but recovery and reuse is like 99%. Lithium is less toxic, but recycling is difficult.

LinuxBender 5y ago

Perhaps lead is not so environmentally friendly? Here [1] are some of the reasons li-ion is currently preferred. This will change with time. I am holding out for the 3D printed solid state batteries which are not mentioned on that page but soon to be in mass production. [1] - https://news.energysage.com/lithium-ion-vs-lead-acid-batteries/ https://news.energysage.com/lithium-ion-vs-lead-acid-batteri...

jseutter 5y ago

Li-Ion has dropped in price to the point where it is cheaper than lead-acid. To come up with a realistic lifetime cost you have to factor in: - Cycle count (lead-acid ~500, li-ion 1000-3000) - Usable capacity (lead-acid 50%, li-ion 80%) - purchase cost (lead-acid $n, li-ion > $n) I'm about to over-generalize, but to get good lifetime out of your batteries, you only discharge lead-acid to 50% of its rated capacity, whereas li-ion has good cycle life working between 10-90% state of charge. You have to buy more lead-acid than you do li-ion to get the same usable storage. Then, your lead-acid batteries will degrade significantly after 500 charge-discharge cycles. The li-ion batteries will tolerate 2-6 times more cycles before significant capacity loss. Environmental friendliness is sort of a wash. Lead-acid is more toxic, but recovery and reuse is like 99%. Lithium is less toxic, but recycling is difficult.