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HOMER Pro 3.10

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Capacity Shortage

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A capacity shortage is a shortfall that occurs between the required operating capacity and the actual amount of operating capacity the system can provide. HOMER keeps track of such shortages and calculates the total amount that occurs over the year.

For example, in a simple system consisting of a 50 kW AC generator serving an AC load:

If the load is 30 kW and the required operating reserve is 15 kW, the required operating capacity is 45 kW and the actual operating capacity is 50 kW, so there is no capacity shortage. The generator operates at 30 kW to meet the load, and the 20 kW of operating reserve it provides satisfies the requirement.

If the load is 40 kW and the required operating reserve is 12 kW, the required operating capacity is 52 kW and the actual operating capacity is 50 kW, so the capacity shortage is 2 kW. The generator provides only 10 kW of operating reserve in this situation, not enough to satisfy the requirement.

If the load is 55 kW and the required operating reserve is 0 kW, the required operating capacity is 55 kW and the actual operating capacity is 50 kW, so the capacity shortage is 5 kW (and the unmet load is also 5 kW).

If the load is 55 kW and the required operating reserve is 20 kW, the required operating capacity is 75 kW and the actual operating capacity is 50 kW, so the capacity shortage is 25 kW (and the unmet load is 5 kW).

Note: It is possible to have a capacity shortage on one bus and excess electricity on the other in the same time step if there is an undersized converter or a converter without the "Parallel with AC generator?" option selected.

See also

Required Operating Reserve

Maximum Annual Capacity Shortage

Total Capacity Shortage

Capacity Shortage Fraction