ARR

PJM’s latest crisis—the underfunding of financial transmission rights that we’ve seen over the last few years—pushes regulators right to the edge. How far do they trust wholesale power markets? Do they accept the idea, proven by a famous economist, that freely traded financial instruments can work just as well—better even—than firm, physical contract rights?

In PJM’s case, we are told, the problem occurs when too much negative congestion shows up in real-time balancing. But if congestion is bad, shouldn’t negative congestion be good?

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.