Two groups of municipal utilities in Texas, long critical of electric power deregulation in Texas and ERCOT in particular, have joined forces to issue a report, “The story of ERCOT: The grid operator, power market & prices under Texas electric deregulation.” The municipals describe the report as examining “governance issues related to ERCOT as an organization as well as deregulation issues related to ERCOT as a region.” In general, they assert that ERCOT has been costly, has suffered some significant episodes of mismanagement, the market hasn’t been as competitive as needed, and that power prices have been too high in the ERCOT region as a result.
Overall “The story of ERCOT” looks like a pretty good effort. ERCOT is a complicated entity, but worth understanding. The report contributes to a better understanding of ERCOT. But in the one section I chose to examine carefully, I was less satisfied.
Among the questions they ask is the one I pulled for the title, “Is the deregulated market in the ERCOT region sufficiently competitive?”, addressed specifically on pages 70-71. Here the report authors have a handful of complaints:
- “Questionable trading practices … very similar to those that helped undermine the California market … known as ‘hockey stick’ bidding.”
- The largest generator, TXU (now Luminant), was frequently a pivotal supplier in the market – able to set market price regardless of the actions of competitors.
- TXU was charged with market power abuse by the PUC in 2005. (A recommended fine of $210 was later reduced to $15 million.)
- Another company acknowledged in engaging in practices very much like hockey-stick bidding in 2007, “which has been found to violate market rules elsewhere in the nation.”
Hockey stick bidding, in which a generator offers the last few megawatts of power at a price substantially above the marginal cost of supplying that power, is a problem. If the power market were always competitive, consumers could be agnostic about individual generator’s offers; occasionally conditions will give generators temporary-but-substantial amounts of market power. These brief moments of market power are not always predictable, but hockey stick bidding means that generators don’t have to guess when they have market power, they just use a bidding strategy in which most of their power is offered at competitive levels and the last tiny bit at monopoly prices. The market in effect reveals that the generator has market power by dispatching all of the unit’s power, and having revealed the market power the market then does the generator the favor of automatically exercising it on the generator’s behalf.
There are arguments for and against allowing generators full flexibility in their offers, including allowing hockey stick bids, but on net consumers are right to oppose the practice. (I’m not at all sure what they mean by “very similar to those that helped undermine the California market”; California’s market fell mostly due to a host of other kinds of bad market design choices which exposed the market to manipulation and kept the consumer-side of the market mostly unable to protect itself.)
Luminant remains a large player in the market, with a market share that should continue warranting special attention from the PUC and ERCOT’s independent market monitor. The report doesn’t mention that Luminant has entered into a “Voluntary Mitigation Plan” (VMP) in 2008 as part of the settlement producing the $15 million fine. The point of the VMP was to deprive Luminant of the ability to exercise any market power. If the municipals have continuing concerns with Luminant then it would be useful to know what is wrong with the VMP.
I tried tracking down the reference to “another company … engaging in practices very much like hockey-stick bidding in 2007.” A footnote points to page 11 in Jay Zarnikau and Parviz Adib, “Will the Texas market succeed, where so many others have now failed?” (Available from Frontier Economics), but I didn’t find an explanation there. Generally speaking, the Zarnikau and Adib paper takes a more optimistic tone than the municipals’ report does.
Overall, in this brief section of the paper, I would have liked a little more analysis and not just a list of complaints. It is one thing to see apparent problems, but much more useful to diagnose the sources of the problem and suggest improvements.