PPT Slide
Problem 1.2: Economic Dispatch of Electric Power Plants ? Variable ? Case
The purpose of this problem is to explore the principles of classical economic dispatch of thermal power plants. Suppose an electric utility’s generating resources consist of two generating units having the following operating costs and operating ranges: Unit 1: C1(P1) = 0.1 P12 - 100P1 + 85,000 ($/h), 500 MW £ P1 £ 1500 MW
Unit 2: C2(P2) = 160 P2 + 20,000 ($/h), 500 MW £ P2 £ 1000 MW
Part A: Develop the minimum production cost strategy (i.e., specify the output power of each unit in terms of the load power PL = P1+ P2) over the entire range of (feasible) load power.
Part B: Use your results from Part A to determine the most economical output power (in MW) of each unit, the total production cost (in both k$/h and ¢/kWh) and the system incremental cost (in ¢/kWh) all for a load of 1922 MW.
Part C: Suppose one of the utility’s customers adds to the 1922 MW load of Part B by switching on a 100 Watt incandescent lamp. How much does it cost the utility to serve this additional load and how much should the customer pay for it? Give your answers in ¢/kWh.
Part D: What is the production cost (in both k$/h and ¢/kWh) of each unit at minimum output power? Repeat for maximum output power. What is the average incremental cost (in ¢/kWh) of each unit. Compare and contrast all these costs for each unit. How do the energy costs compare with those of your own (residential) electric bill? Do the quadratic cost equations resemble those of real (actual) power plants?
Part E: At what power output does each unit produce energy most economically and what is the production cost (in both k$/h and ¢/kWh ) of each unit for that output?
Part F: At what power output does each unit produce energy most efficiently and what is the production cost (in both k$/h and ¢/kWh) of each unit for that output?
Part G: If the load equals the sum of the output powers calculated in Part E, what is the most economical way to operate the units and what is the total production cost (in k$/h and ¢/kWh) of the two-unit power system? How do your answers here compare with those of Part E? Repeat for Part F. How would you explain any differences to a layman?
Part H: For the load of Part B, what is the operating strategy which will maximize the total overall energy efficiency of the power system? How do your answers here compare with those of Parts B and G?