8. calculating the corresponding incremental fuel cost λ of the plant

16. The problem is to find the real power generation for each plant such that cost are minimized, subject to:

17. Meeting load demand - equality constraints

20. The total spinning reservefrom all the generating units must be greater than or equal to the spinning-reserve requirement of the system. This can be either a fixed requirement in MW or a specified percentage of the largest output of any generating unit.

21. Minimum up time : Once the unit is running, it should not be turned off immediately.

22. Minimum down time: Once the unit is de-committed (off), there is a minimum time before it can be recommitted.

23. The output powerof the generating units must be greater or equalto the minimum powerof the generating units.

25. Unit input-output characteristics is linear between zero output and full load.

26. Start up cost are fixed amount.

29. The lambda-iteration method is a good approach for solving the economic dispatch problem.

30. generator limits are easily handled

31. penalty factors are used to consider the impact of losses

32. Economic dispatch is not concerned with determining which units to turn on/off (this is the unit commitment problem).