Should variable costs include non-fuel operating and maintenance costs?
Some estimation of these variable O&M costs should be included. Because of the “art” with which each company develops them, and because there is no agreement as to what they should be, we have adopted generic values. If anyone could provide better estimates, they should be used. We recommend that generic values be applied universally to all generating units, by technology and size category. 4) Q. Should NERC s PTDF and Flowgate limits be used? We have used data similar to the NERC PTDF values in the IREMM Model. It seems reasonable that the use of a revised set of PTDF could adequately represent the critical flows in a transmission system. The current format of the iIDC on the NERC web site is too cumbersome to use, but if the data were made available in other formats, they could be incorporated easily into the IREMM Model. The current complement of 1400 flowgate elements in the PTDF database is probably too large for a horizontal market power screen and should probably be reduced to 2
