MWh

.. appreciate your are trying to get a sense of scale, but it’s important to note that short-duration batteries are not there as a generator to serve load, they are good for providing peak demand support to the system and the local LV distribution network, and to help regulate frequency.

I’m not familiar with the US market environment, but in Australia where we have a number of VPP operators, including Tesla, it the latter service that is the most used.

Frequency regulation services are associated with absorbing and injecting energy into the power grid over milliseconds.

Since it takes at minimum 4 hours to drain each battery (3.3KW discharge rate), a better question would be what percentage of peak demand power they can provide.

Max power: 3.3 * 50000 = 165MW. Peak demand for 2020: 47121MW (18th August 15:57). Percentage of power: 165 / 47121 = 0.35%

Using the yearly average instead (31713KW): 165 / 31713 = 0.52%

I found some numbers for total PG&E generation in 2017 and based on that 675mWh would be about 10 minutes worth of power.