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RestlessAmbivert t1_ivdotc8 wrote

Reply to comment by trankillity in Rooftop solar trumps all fossil fuels as renewables smash more records on main grid [Australia] by EnergyTransitionNews

Are batteries more efficient in use and in terms of sustainably than physical storage systems, i.e., those that lift pillars/weighted sleds with excess power then convert it back to electricity when the weight is released during non-daylight hours?

Just curious if you knew offhand, hadn't looked into them in detail.

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cowlinator t1_ive8pvd wrote

Pumped hydroelectricity storage is 87% efficient, but requires huge reservoirs. A brand new lithium ion battery is 88% efficient, but this goes down significantly over the battery lifespan. The efficiency of mechanical gravity storage systems varies widely but is usually under 80%

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trankillity t1_ivdu7kc wrote

I don't know offhand sorry, but I imagine there's a LOT of energy lost in those systems due to the physics of mechanical energy transfer. That being said, I've heard there's some very efficient underground flywheel systems that have been implemented in the last few years.

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Surur t1_iveo4u3 wrote

Yes, round trip is above 90% for batteries and around 80% for weights for example, and storing energy in batteries is a lot more energy dense than via gravity potential.

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