Small wind / Buyer questions
Energy and economics
Will a small wind turbine reduce my electricity demand charge?
The short answer
It might, but annual wind kWh cannot establish demand-charge savings. The result depends on output during the intervals that set the bill, the utility’s measurement rules and any demand minimums or ratchets. Wind can reduce energy purchases while leaving the billing peak unchanged. Model the actual tariff against aligned load and generation records before including a demand-charge benefit.
Inspect the demand-setting intervals
Identify how the tariff measures demand, which periods are eligible and whether earlier peaks affect later bills. Then align generation and load using the same timestamps and interval lengths. A monthly average or annual self-consumption percentage cannot show the maximum imported power.
Keep the distinction between a measured instantaneous peak and a billing-demand interval. The applicable tariff defines what is charged. Include applicable minimum-demand terms in every modeled billing period. These details vary, so do not apply a generic demand-charge saving to every commercial wind project.
Compare three illustrative intervals
Assume three 15-minute intervals, no storage and no other loads:
| Interval | Site load | Wind | Grid import |
|---|---|---|---|
| 1 | 30 kW | 0 kW | 30 kW |
| 2 | 28 kW | 6 kW | 22 kW |
| 3 | 25 kW | 7 kW | 18 kW |
Wind offsets 3.25 kWh over these intervals, but the maximum import remains 30 kW. Even this simple record therefore shows energy reduction without peak reduction. It is not a full monthly billing calculation.
Keep the forecast conservative and reproducible
Run the full billing period, including calm periods and outages, and apply the real rate schedule. If a spreadsheet credits a lower demand peak, identify the exact interval responsible and test sensitivity to different weather years.
A storage system or load-control strategy may change the result, but it adds its own equipment, control and cost requirements. MARSTON does not supply its own battery product; any third-party storage and its interfaces require a separate project assessment.
Sources
Examples are illustrative. Confirm product-specific performance, compatibility and supply scope in the applicable documents.