Calculator Inputs
Example Data Table
This sample shows the type of values used by the calculator.
| Unit | Min MW | Max MW | a | b | c | Ramp MW/h | Emission t/MWh |
|---|---|---|---|---|---|---|---|
| Unit A | 20 | 120 | 0.0040 | 8.20 | 250 | 40 | 0.55 |
| Unit B | 35 | 180 | 0.0032 | 7.80 | 330 | 65 | 0.48 |
| Unit C | 10 | 80 | 0.0065 | 9.40 | 120 | 25 | 0.72 |
| Unit D | 50 | 220 | 0.0028 | 8.60 | 410 | 85 | 0.42 |
Formula Used
Target generation: Demand MW × (1 + Loss % ÷ 100)
Reserve needed: Demand MW × Reserve % ÷ 100
Generator cost: C(P) = aP² + bP + c
Emission adjusted linear cost: b adjusted = b × Fuel Multiplier + Emission Rate × Emission Price
Incremental cost: dC/dP = 2aP + b
Economic dispatch rule: Active generators are scheduled until their incremental costs are balanced, while minimum and maximum limits are respected.
Ramp capability: Sum of ramp rates × Ramp Window Minutes ÷ 60
How To Use This Calculator
- Enter the demand load in megawatts.
- Add expected transmission loss percentage.
- Set the reserve margin required for safe operation.
- Enter fuel and emission assumptions.
- Fill generator minimums, maximums, and cost curve values.
- Tick only the units that are available for dispatch.
- Press the calculate button.
- Review dispatch, costs, reserve status, ramp status, and charts.
- Export the report as CSV or PDF for records.
Why Optimal Dispatch Matters
Optimal dispatch connects demand with the cheapest safe mix of generation. It is useful for plants, microgrids, fleets, and industrial energy teams. The goal is simple. Meet the load. Respect each unit limit. Keep enough reserve. Avoid hidden fuel and emission waste. A small change in load can move production from one unit to another. That shift can change total cost quickly.
How the Method Works
Each unit has a heat cost curve. The curve uses fixed, linear, and quadratic cost terms. The calculator adjusts those terms with fuel and emission inputs. It then searches for one marginal cost value. That value is called lambda. When units are not stuck at minimum or maximum output, their incremental costs become nearly equal. This creates a balanced schedule.
Limits and Practical Checks
Real dispatch is not only math. A unit may have a minimum stable output. It may have a hard maximum. It may also have a ramp limit. This page checks those limits before showing a result. It also compares spare capacity with the requested reserve margin. If reserve is short, the result warns the operator. That makes the answer easier to review.
Using Results in Daily Planning
The result table shows megawatts, cost, share, unused capacity, and emissions. The chart helps compare units fast. The sensitivity table shows how total cost changes when load moves down or up. This is helpful for day ahead review. It also supports what if discussions with managers or customers.
Better Decisions
A dispatch answer should not replace operator judgment. It should support it. Weather, outages, maintenance, contracts, and local rules can change the final schedule. Use this calculator as a planning guide. Confirm final dispatch with approved operating procedures, real time telemetry, and market instructions.
Data Quality Tips
Good inputs make the schedule stronger. Check fuel prices before each run. Update emission rates when fuel blend changes. Review minimum and maximum output after maintenance. Remove unavailable units from the form. Keep demand forecasts realistic. Compare the exported report with meter data later. This habit improves future assumptions and reduces repeated dispatch mistakes. It also builds trust across busy operations teams.
FAQs
1. What is optimal dispatch?
Optimal dispatch is the process of assigning load to available units at the lowest practical cost. It also checks operating limits, reserve margin, ramp ability, and emissions.
2. What does the quadratic cost curve mean?
The curve estimates generator operating cost at different output levels. The a term shows rising cost, b shows linear cost, and c shows fixed cost.
3. Can I use this for a microgrid?
Yes. You can enter small generators, battery units, or backup units. Use cost values that match your local fuel, operating, and emission assumptions.
4. Why does reserve gap matter?
Reserve gap shows whether unused available capacity can cover the selected reserve requirement. A gap means the system may need more capacity or less demand.
5. What is lambda in dispatch?
Lambda is the shared marginal cost used in economic dispatch. Units not at limits should have similar incremental costs in the final schedule.
6. Why is my result limited?
A limited result appears when demand is below total minimum output or above total maximum capacity. The calculator then shows the nearest possible schedule.
7. Are emission costs included?
Yes. Emission price is added to the linear cost term using each unit emission rate. This helps compare cleaner and higher emitting units.
8. Can I export the dispatch report?
Yes. After calculation, use the CSV button for spreadsheet work or the PDF button for a formatted report with summary and unit dispatch data.