A time-of-use tariff makes the hour attached to each kilowatt-hour matter. For a mining fleet, the useful comparison is energy cost at each rate while keeping the operating load and hashrate fixed. That isolates the tariff effect from changes in mining output.
Illustrative assumptions
Work the energy before the bill
At 100 kW, the load uses 100 kW × 16 peak hours = 1,600 peak kWh per day and 100 kW × 8 off-peak hours = 800 off-peak kWh per day. Across seven identical days, that is 11,200 peak kWh and 5,600 off-peak kWh, or 16,800 kWh in total.
| Seven-day case | Peak energy | Off-peak energy | Energy cost |
|---|---|---|---|
| Flat peak-rate baseline | 16,800 kWh × $0.12 | — | $2,016 |
| Time-of-use rates | 11,200 kWh × $0.12 | 5,600 kWh × $0.06 | $1,680 |
- Flat baseline: 16,800 kWh × $0.12/kWh = $2,016.
- Window-priced case: (11,200 kWh × $0.12/kWh) + (5,600 kWh × $0.06/kWh) = $1,344 + $336 = $1,680.
- Illustrative energy-cost difference: $2,016 − $1,680 = $336 for the week.
Apply the tariff to a real site
Ferrohive records site power windows as weekday, start hour, end hour and price per kWh. The ledger applies the matching rate at each hourly slab’s midpoint in the site’s local time; hours with no matching window use the configured default rate. Check that the windows and default together represent the site’s actual tariff before comparing the ledger with a bill.
This example prices a constant 100 kW load across the two tariff periods; it does not model turning miners off, shifting hashrate, demand charges, curtailment or any other contract terms. If operating decisions change hashrate or uptime, revenue changes too and must be included in the margin comparison.
Open /fleet and choose a site’s Power windows link to enter its schedule. The fleet page supplies the concrete site-specific route, and signed-out visitors are sent through the app’s login flow.
Sources
- Ferrohive power-window form and route: src/app/(dashboard)/sites/[id]/power-windows/page.tsx.
- Power-window fields and rate validation: src/lib/contracts/power-windows.ts.
- Ledger rate lookup and energy-cost calculation: src/lib/business/rig-ledger.ts (priceAtMidpoint and aggregateLedger).
- Site-specific Power windows links: src/components/custom/fleet-sites-block.tsx, reached from /fleet.