About 30 states have begun (em

either through the legislature, the utility commission, informal working groups, or some combination of these (em to consider issues such as retail wheeling,...

of actual losses to the losses that would be recovered if the marginal loss rates were applied to all generators.

2 $18,232 = $20 x 500 + $21 x 392. $122 = $18,232 - $18,110.

3 The figures for the scaled marginal cost approach are derived as follows. Without losses, the 892-MW system load is met by 744I MW and 147G MW from the western and eastern generators, respectively. The marginal loss rates for these generators are 0.02197 (=0.05 x 392/892) and -0.02803 (=-0.05 x 500/892), respectively, where 0.05 is the marginal line loss for this case in which line flows average 250 MW. Total marginal losses are 16.33 MW (=0.02197 x 744I) and -4.13 MW (=-0.02803 x 147G), respectively. Scaled losses are 8.36 MW (=6.25 x 16.33/(16.33-4.13)) and -2.11 MW (=6.25 x -4.13/(16.33-4.13)), respectively. Break-even prices are $20.22 = $20 x (753J)/ 744I and $20.70 = $21 x (145J)/147G, respectively.

4 Two-thirds of any load increment at bus 1 flows to bus 3 over line 1-3. One-third of any load increment at bus 2 flows to bus 3 over line 1-3. Decreasing bus 1 output by 1 MW therefore decreases flow on line 1-3 by two-thirds of a megawatt, while increasing bus 2 output by 2 MW increases flow on line 1-3 by that same two-thirds of a megawatt. In simultaneously decreasing bus 1 output by 1 MW and increasing bus 2 output by 2 MW, flow on line 1-3 is left unchanged, while supply increases by the 1 MW needed to serve a 1-MW load increment at bus 3.

5 In the context of the efficient dispatch of Figure 4, a 1-MW increase in the capacity of line 1-3 would allow generator A2 to reduce output by 3 MW while generator B1 increased output by 3 MW. The cost change attributable to a 1-MW relaxation of the line 1-3 constraint thus is -3 x $25 + 3 x $15 = -$30.

**Articles found on this page are available to Internet subscribers only. For more information about obtaining a username and password, please call our Customer Service Department at 1-800-368-5001. **