Understanding Net Heat Rate Dispatch
Economic dispatch decides how much power each generator should make. The goal is simple. Meet demand at the lowest practical cost. The net heat rate adds another useful view. It shows how much heat energy is needed for each net kilowatt hour.
Why Heat Rate Matters
A lower heat rate usually means better conversion efficiency. Plants with poor heat rates need more fuel for the same output. Dispatch teams compare heat rate, cost curves, unit limits, and reserve needs before choosing a loading plan. This calculator combines these checks in one place.
How The Dispatch Works
Each unit uses a quadratic cost curve. The curve has a fixed part, a linear part, and a squared output part. The tool finds a common incremental cost value, called lambda. Units with lower incremental cost receive more load, while still respecting minimum and maximum limits. If a unit reaches a limit, the remaining units carry the balance.
Net Heat Rate Review
After dispatch is solved, the calculator estimates total heat input. It also divides total heat input by net generation. The result is shown in Btu per kWh. This value helps compare operating points. It can also show when a plant is running away from its efficient range.
Operational Use
Operators can include a loss allowance and a reserve margin. These options create a more realistic target than raw load alone. The reserve entry is useful when a plant must keep spare capability online. The loss entry helps represent auxiliary losses, station service, or transmission allowances.
Cost And Planning Value
The cost table gives unit output, hourly fuel cost, heat input, incremental cost, and loading status. Engineers can export the table for reports. Analysts can test different loads, fuel prices, and unit limits. The example data offers a starting case for practice.
Best Practices
Use accurate coefficients from plant tests or approved performance models. Check that minimum and maximum limits match the current operating condition. Review warnings when demand exceeds available capacity. Treat the result as a planning aid. Final dispatch decisions should follow grid rules, plant safety limits, and operator judgment. Small load changes can shift the best mix quickly. Recheck inputs after derates or fuel changes.