The replay that reproduced every event and changed the bill
Larkspur Energy is a fictional retail electricity supplier. It sells Larkspur Flex, a plan that prices consumption by time-of-use band and adds a demand charge derived from the largest half-hour a site draws inside a peak band. Its customers are homes and small businesses. It does not own meters: a fictional metering agent, Gridpost Metering, reads them and publishes the data. It does not own the market either — it submits a daily settlement position to a regional market operator and lives with what the operator settles.
Sanne Vermeer (streaming platform engineer) owns the two stream jobs that turn meter reads into money, and the tooling that replays them. Dov Aharoni (settlement analyst) owns the daily market submission and authorises backfills when metering data goes missing. Marta Oyelaran (billing operations lead) owns customer notices, corrections, and the policy that decides which plan a site is eligible for. Marta owns the consequence of this incident and was not part of the repair that caused it.
How a half-hour of electricity becomes a bill
Larkspur Flex is defined by five rules. All five are Larkspur's own, or its market's; none describes a real market.
| Rule | Value |
|---|---|
| Rate classes | OFF_PEAK, SHOULDER, PEAK, CRITICAL_PEAK |
| Band adjustment applied to each rated interval when computing the demand metric | 1.01 / 1.02 / 1.06 / 1.09 respectively |
| Coincident peak | Per half-hour, sum the site's adjusted kWh across its meter points; take the maximum over half-hours classed PEAK or CRITICAL_PEAK; double it to express kW |
| Plan eligibility | A rolling twelve-month coincident peak above 25 kW moves the site off Flex onto a demand tariff, with 14 days notice |
| Market submission | Trading day T is submitted on T+1, and the revision window closes on the 15th of the following month |
A site can have several meter points — a main supply, a dedicated circuit, a charger — and the coincident peak is a property of the site, computed across all of them. That detail is the whole story, and it looks like nothing.