In competitive power markets based on locational marginal pricing (LMP), the facts sometimes conflict with popular belief. Most notably: 1. When there’s congestion, the books don’t balance, and ratepayers always pay more than the generators receive. The difference is sometimes called “congestion cost.” 2. Congestion in a competitive market doesn’t necessarily increase ratepayers’ costs; and 3. Reductions in LMP are incomplete and sometimes misleading measures of economic benefits of transmission upgrades. These three facts and their implications should be considered in transmission planning, market design, tariffs, and system operations.

Commission Watch

PJM/Midwest Market:

Should transmission owners get paid extra for distance and voltage?

While the Midwest now appears set on competitive bidding for the electricity commodity, taking from PJM such tried-and-true elements as locational marginal pricing (LMP), financial transmission rights (FTRs), and a day-ahead market with a security-constrained dispatch, the region remains split over the pricing of transmission.