In commercial operations, electricity is rarely billed at a flat rate. Under industrial power contracts—such as KEPCO Industrial Service (General/Eul schedules) in South Korea or regional PPA agreements across East Asia—electricity rates are segmented into three distinct daily time bands: off-peak (night), shoulder (standard hours), and peak (mid-day summer/winter peaks).
The Three-Tier Tariff Spread
During summer peak hours (typically 14:00 to 17:00), peak industrial power rates can reach nearly 2.8 times the off-peak overnight tariff. If an operator keeps high-draw hardware running continuously without evaluating the instantaneous hash price, each terahash produced during those three peak hours generates negative net cash flow.
Calculating the Curtailment Equilibrium
The mathematical condition for profitable operation is: Gross Revenue per Machine per Hour (₩) > Total Electricity Cost per Machine per Hour (₩) + Marginal Depreciation (₩).
When electricity cost per kilowatt-hour exceeds the gross reward yield of the machine's wattage consumption, continuing to hash costs more in utility billing than the coin value earned. Our workshop models teach operators how to construct automated API-triggered relays that gracefully spin down non-critical hash boards as peak tariff hours begin, then resume full autotuning as off-peak rates commence at 23:00.
Avoiding Peak Demand Charge Traps
Beyond hourly consumption fees (kWh), industrial tariffs impose substantial 'Demand Charges' based on the single highest 15-minute rolling average power peak (kW) recorded during the billing cycle. Starting all machines simultaneously following a maintenance window can set an artificially high billing baseline for the next twelve months. We demonstrate staged ramp-up sequences that protect operational margins.