Flywheels
Flywheels are a proposed solution to part of the energy storage problem.
Flywheels store energy mechanically by spinning a heavy rotor at high speeds. This has been implemented before, both inside vehicles
Viability
#Need for iron | Not too bad |
#Need for rare-earth magnets | Might be an issue[RESEARCH needed] |
#Energy in manufacturing | Unknown[RESEARCH needed] |
#Charge/discharge losses | Tradeoff with the other issues[RESEARCH needed] |
#Suitable for vehicles? | Probably not suitable enough[RESEARCH needed] |
Need for iron
If flywheels are made mostly of steel (which is mostly iron), we would have enough metal to build enough of them:
Note: This is roughly the amount of on-grid energy consumption that we might need energy storage for. It consists of - for example - lighting, heating, appliances, and other energy used in homes and other buildings. We don't count industrial here, because we can assume (in principle) that most factories could operate during peak sunlight/wind, needing negligable energy storage.
The source doesn't specify whether this is steel from newly-mined iron or steel from recycling scrap. Probably it's both combined.
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How much energy would it take to refine all that steel?
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Energy in manufacturing
However, the energy needed to manufacture the flywheels from the steel, might be vastly more. This page needs more research.
Need for rare-earth magnets
It is unknown how much of other metals might be needed to make the flywheel systems - for example the rare earth magnets involved in the motor/generator components. This page needs more research.
Charge/discharge losses
Solutions might need a lot of rare-earth magnets or energy in manufacturing.[RESEARCH needed]
Suitable for vehicles?
Flywheel-based vehicles have existed for over a century, but they don't store enough energy to last more than a kilometer. Perhaps vacuum-sealed electrical type of flywheel could store more energy