4 ms·

I would say that home batteries like the Power Wall seem like a nice solution. However I am a bit worried about the lifespan of those batteries and what happen

I would say that home batteries like the Power Wall seem like a nice solution. However I am a bit worried about the lifespan of those batteries and what happen to them at their end-of-life (recycling? CO2e cost of making a new one?...)

blincoln 4y ago
For standalone houses, seems like a bank of traditional lead-acid batteries like datacenters use is a better option. Doesn't require exotic materials, EOL handling is well understood at this point, etc. If I'm doing the math right, every ten car batteries in the bank should get you about 8 kWh. The average home in the US uses about 11,000 kWh/year[1], or about 30 kWh/day, so a bank of 20-60 batteries seems like a good starting point, depending on how much reserve capacity one is comfortable with, how variable solar generation is, etc. That's an up-front cost of about $4,000-$12,000 every 5-7 years, but at least at the low end that should actually be cheaper than paying for electricity from the grid over the same period. A 20-battery bank should fit in about the same footprint as a refrigerator. That's also significantly cheaper than a PowerWall of the same capacity[2], which was $7,500/14 kWh ($535/kWh versus about $250-$275/kWh for lead-acid) before Tesla stopped selling them without a solar panel bundle. For apartments and other colocated housing, it might still make sense as long as there was some sort of central vault for the battery bank. [1] https://www.eia.gov/energyexplained/use-of-energy/electricity-use-in-homes.php https://www.eia.gov/energyexplained/use-of-energy/electricit... [2] https://solarmetric.com/learn/tesla-powerwall-review-costs-specs/ https://solarmetric.com/learn/tesla-powerwall-review-costs-s...
- henearkr 4y ago
  Thanks for the thourough estimations! However I strongly advise against buying lead batteries, which are very dangerous for the health and environment (arguably not while they have not yet reached their end-of-life, but once expended a lot of them end up being dumped into the wild, and I am not even confident in their recycling).

blincoln 4y ago

For standalone houses, seems like a bank of traditional lead-acid batteries like datacenters use is a better option. Doesn't require exotic materials, EOL handling is well understood at this point, etc. If I'm doing the math right, every ten car batteries in the bank should get you about 8 kWh. The average home in the US uses about 11,000 kWh/year[1], or about 30 kWh/day, so a bank of 20-60 batteries seems like a good starting point, depending on how much reserve capacity one is comfortable with, how variable solar generation is, etc. That's an up-front cost of about $4,000-$12,000 every 5-7 years, but at least at the low end that should actually be cheaper than paying for electricity from the grid over the same period. A 20-battery bank should fit in about the same footprint as a refrigerator. That's also significantly cheaper than a PowerWall of the same capacity[2], which was $7,500/14 kWh ($535/kWh versus about $250-$275/kWh for lead-acid) before Tesla stopped selling them without a solar panel bundle. For apartments and other colocated housing, it might still make sense as long as there was some sort of central vault for the battery bank. [1] https://www.eia.gov/energyexplained/use-of-energy/electricity-use-in-homes.php https://www.eia.gov/energyexplained/use-of-energy/electricit... [2] https://solarmetric.com/learn/tesla-powerwall-review-costs-specs/ https://solarmetric.com/learn/tesla-powerwall-review-costs-s...

henearkr 4y ago
Thanks for the thourough estimations! However I strongly advise against buying lead batteries, which are very dangerous for the health and environment (arguably not while they have not yet reached their end-of-life, but once expended a lot of them end up being dumped into the wild, and I am not even confident in their recycling).