How should I value wind electricity that my site cannot use?

The short answer

Determine whether surplus energy may be exported, how exports are settled and whether generation must be reduced when neither use nor export is available. Value only the energy that is actually consumed, credited or sold under the applicable arrangement. Do not assume every generated kWh receives the site’s retail purchase price or that an annual surplus can be carried forward automatically.

Make the destinations explicit

For each interval, distinguish generation used immediately, energy exported, energy sent into an approved storage arrangement and output curtailed or otherwise unavailable. Storage energy is not yet final useful energy: losses and later use must be accounted for without counting the same kWh twice.

The settlement contract then determines the value of each destination. Some arrangements credit energy across a period; others pay for exports differently. Check the actual rules rather than importing a generic net-metering assumption from another market.

Use a destination-based example

Illustrative annual quantities: 15,000 kWh could be generated at the agreed AC boundary before curtailment. The site uses 9,000 kWh, exports 4,000 kWh and curtails the remaining 2,000 kWh before it is generated. Actual AC generation in this simplified case is 13,000 kWh.

Destination	Assumed value	Annual contribution
Self-use: 9,000 kWh	0.20/kWh	1,800
Export: 4,000 kWh	0.05/kWh	200
Curtailed potential: 2,000 kWh	0	0

The total is 2,000 currency units before project costs. Valuing all 15,000 kWh at 0.20 would incorrectly give 3,000.

Improve the useful share before assuming a larger turbine

Explore whether suitable loads can operate during windy periods and whether the export constraint is fixed or controllable. Any change must preserve the site’s operational requirements. More equipment is not automatically the least-cost response to surplus generation.

For the equipment review, state the permitted export, metering boundary and intended surplus-energy behavior. Confirm the proposed controls and protection for that operating case. The example is original arithmetic, not a claim that a MARSTON system includes a particular export-control function.