RE: Why can’t wind turbines store their power in large batteries? (Same for solar cells.)
They absolutely can. The question is cost, both monetary cost and environmental cost.
The real cost is that energy storage in batteries scales linearly with electrical storage capacity. For any particular battery technology, a battery which stores 10 kilowatt-hours (kWh) of electricity is going to use 10 times as much anode and cathode material as a battery which can hold one kWh , take 10 times the volume and it will weigh 10 times as much. A 10 kWh battery causes 10 times as much rock mining as a 1 kWh battery, and a fire in a 10 kWh battery would dump 10 times as much toxic metals into the air as a 1 kWh battery fire would.
The relationships of electrical storage capacity to material used in batteries are all linear, ie one-to-one; there is no way in physics to get around that.
The apparent drop in battery prices is — for the moment — due to larger scale manufacture, but eventually the factories can’t get any better and then the costs of materials for those batteries will dominate. Note, however, that the cost of mining is NOT linear. If you take 10 times as much ore out of the ground you are going to be forced to go to lower grade ore which will increase the cost per battery, how much depends on market forces, environmental regulations, etc.
But we are not talking a mere factor of ten here. Most people have a few pounds of batteries in their home now. If you want to use “renewable energy” to power your home then you are talking TONS of batteries needed to compensate for the grotesque unreliability of solar and wind power. So we are talking an increase of at least 3 orders of magnitude in battery material usage, ie we would have to mine at least a thousand time more battery material than we have been mining. Can we afford that cost, financial and environmental?
I think not.
I did a rough calculation of what it would take to keep an “average” home running for a day when the wind calmed and clouds blocked the sun using off-the-shelf, industrial quality, lead-acid batteries. It is here:
Jeff Barry’s answer to When/would it be possible to rely only on renewable energy for the whole earth? What makes it that we can’t?
I did a similar calculation on a national scale using lithium batteries (which are MUCH lighter than lead-acid batteries for a given kWh capacity): You will need about 50 million metric tons of battery material to provide backup power to the US for JUST ONE DAY.
Can we afford that cost, financial and environmental?