Some eye opening facts and calculations. People do understand that batteries do not actually generate electricity.
The Home-Based Battery Storage Fantasy
In the U.S., a typical residential household consumes around 10,800 kWh annually, or about 30 kWh per day. Of course, the amount varies depending on the size of home, the region of the country, and the season of the year. With electrified space and water heat, some regions of the country where electricity demand now peaks in summer will see demand peak in winter, while existing winter-peaking regions will see winter demand spike even further.
According to a U.S. Department of Energy model, a heat pump in a typical home will consume about 5,500 kWh annually. That alone represents a 50% increase in electricity use. Charging a typical EV adds another 4,300 kWh annually. In total, those will add almost 10,000 kWh of consumption annually, roughly doubling current consumption to about 60 kWh per day, although the increase will be greatest in winter when heating loads peak.
Supplying the additional electricity while ensuring the same level of service reliability (i.e., no extended outages or limiting consumers’ access to electricity because of insufficient supplies) will require enough battery storage to provide electricity at night and over multi-day periods when there is little wind and sun available to recharge those batteries. Although the article recommends using consumers’ EVs to supply electricity, few consumers will likely wish to wake up to an uncharged EV and an inability to travel, especially if there is no stored electricity available to recharge their EVs.
Using the U.S. consumption averages, if existing local distribution systems can serve today’s average load of 30 kWh/day, then enough battery storage must be built to supply the remaining 30 kWh. and, more importantly, the peak power demand of electric heat pumps and EV chargers. A typical Level 2 home EV charger, for example, can draw 20 kilowatts (kW). A heat pump can draw 7 kW.
The largest Tesla Powerwall, which is designed for home use, provides a maximum of 11.5 kW of power and 13.5 kWh of storage under ideal conditions. (When temperatures fall, so does battery capacity and efficiency.) Hence, at least three Powerwall units would be required to provide a typical home with sufficient electricity to supplement existing grid capacity. For one million homes, that means three million Powerwall units providing a maximum of 40.5 million kWh (40,500 megawatt-hours) of battery storage.
https://www.realclearenergy.org/articles/2024/11/21/the_home-based_battery_storage_fantasy_1073913.html