PG&E's non-residential rates aren't that much cheaper than their residential rates. The rate schedules are comically complex so I can't give you insight into what the differences are, but they're showing average rates of $0.42/kWh (A-1, Commercial), $0.19–$0.32/kWh (E-20, Industrial), $0.20–$0.32/kWh (B-20, Industrial), $0.51/kWh (AG-1A, Agricultural), etc., etc.

As was pointed out by another commenter California and Hawaii are outliers, but then again so is Texas (where the uncapped market rate plans socked people with $9,000/month residential bills). Thing is both Texas and California are huge markets, so while parts of the US are much cheaper, parts of the US that are each larger than the UK are quite a bit more expensive.

Honestly I had no idea how pricey the non-residential plans are and I feel like there are almost certainly incentives that would cut the net cost significantly.