Steven M. Brown,
There’s good news and not-so-good news for the New England electric power market. A recently released ISO New England study showed that power plant availability has increased since 1995, an initial sign that the wholesale market there is working as intended. But concerns linger over poor performance from new combined cycle plants and transmission bottlenecks within the region.
The study, which examined New England generating unit availability from January 1995 to December 2000, showed that average unit availability improved slightly from 1995 to 2000. After a dip in availability between 1995 and 1997, due primarily to extended outages of several nuclear plants, it rose again between 1998 and 2000 to a point slightly higher than the 1995 level.
“The bottom line is that implementation of the wholesale markets has not impacted availability of generation throughout New England,” said Stephen Whitley, ISO New England’s senior vice president and COO, delivering the study’s results at a June 15 teleconference.
“The improvement indicates that the market is working as designed,” he said. “Plant owners are responding to economic incentives to keep their plants running when demand is highest.”
While the study showed general consistency in generator availability, it did raise concerns over the performance of certain designs of new combined cycle generating units. A decline in non-nuclear availability in 1999 through 2000 was attributed primarily to seven new combined cycle units that came online during that time period. The low reliability of these new combined cycle designs are related primarily to problematic generator control systems and boiler malfunctions as a result of high temperatures and pressures, Whitley said. He said there are basically three types of new combined cycle units coming online; only two of the three designs are experiencing significant difficulties.
If those design problems are not resolved soon, New England’s mostly positive generator availability statistics could take a hit in the future. Whitley said that nine new plants online this year and 15 more under construction are a mixture of the three new combined cycle designs.
According to Whitley, older combined cycle units in use in New England are operating with an availability rate of about 90 percent. Some of the newer combined cycle designs, however, are operating at only 30 to 60 percent availability. He said the ISO does have some concerns about relying too heavily on these new designs.
“We’re going from about 15 percent gas-fired generation to in the neighborhood of 45 to 50 percent,” he said.
Whitley said the ISO would be working with generation owners and vendors to try to resolve the difficulties as more of the new units are put into service. In the meantime, he pointed out that the region carries sufficient reserve margins to compensate for the loss of any single plant.
Whitley also expressed concerns over New England’s transmission network. As is the case across most of the nation, recent transmission upgrades in New England have been nearly non-existent. Whitley said that several bottlenecks in the region’s transmission system have become apparent making it difficult to move power from north to south. He said that a study is under way to address the transmission issue in New England. Possible solutions include the reinforcement of existing lines, transformers and circuit breakers, and the construction of major new transmission infrastructure.
The generator availability study, commissioned by ISO New England and performed by Merrill Energy of Schenectady, N.Y., was intended as a descriptive statistical analysis of New England’s generating unit availability and an analysis of the underlying trends in that data. It was not meant to be an examination of market power. A separate study to be completed later this year is intended to determine the extent, if any, of market power by comparing marginal cost of energy production and wholesale clearing prices. The report examining market power is due out in fourth quarter 2001.
Whitley said ISO New England intends to take a number of steps following the generator availability study. Going forward, the ISO intends to:
- Continue to monitor and analyze New England’s generating unit availability using the database developed in the study,
- Issue a quarterly report, to be posted on ISO New England’s Web site, documenting historical unit availability data,
- Recommend to the New England Power Pool changes to its system rules and procedures making submission of unit availability data mandatory,
- Start a dialogue with market stakeholders and the regulatory community regarding concerns about unit availability and market efficiency,
- Meet with generator owners and vendors to investigate and discuss means to improve generating unit availability.