Submetering Saves Thousands on EV Charging.

I Vibe Coded a Simulator to Show Exactly How Much.

I'm old enough to have programmed on optical scan cards and young enough to have vibe coded this over a couple of weekend days while watching the Olympics.

Built a submetered EV charging cost simulator — 2,000 lines of React with full California tariff modeling, TOU optimization, and side-by-side bill comparison across PG&E and SCE rate schedules.

My contribution? Domain expertise. Knowing which rates actually matter, how demand charges stack, where the eligibility gotchas are, and what questions a site team needs answered before installing submeters.

The AI wrote the code. I wrote the spec. [The AI also wrote this post].

Most important, as I stress test a variety of scenarios, it becomes clear that any facility operator in CA who layers EV charging on their commercial rate and doesn't submeter is wasting thousands and thousands of dollars.