The California Energy Commission voted unanimously May 5 to issue a ?friendly subpoena? to the California Independent System Operator to obtain critical information on aging power plants for an upcoming study. A formal subpoena was required because federal tariffs prohibit the grid operator from releasing information on plants without an order. Given the potential supply crunch the state is facing, aging plants pose a policy dilemma: they continue to play an integral role in the flow of electricity, but they are inefficient and create more pollution per megawatt-hour than new combined-cycle facilities. The CEC is developing a study assessing aging facilities? impact on the system, how they are operated, and the associated environmental impacts. The study expands on an earlier CEC study and now includes 66 gas-fired units in the state that are 20 years old or older. A May 18 workshop will be held to summarize what the CEC staff has learned about the facilities, and preliminary findings may be discussed in a follow-up workshop next month. ?It is a very important study and will provide an important market signal as to whether the plants are really valued,? said Jesus Arredondo, NRG Energy director of regulatory affairs. If plants are considered essential to reliability, he said, they can be repowered to improve efficiency. NRG and Dynegy are awaiting a certification to retool the old El Segundo plant from the CEC. ?A critical factor is getting repowers permitted on a timely basis,? Arredondo said, which will allow the generator to get a contract for the output. NRG and Dynegy sponsored a bill that would give priority to repowered projects, but it does not look like it will move forward (see <i>Circuit<\/i>, April 16, 2004). According to a new report by the Center for Energy Efficiency and Renewable Technologies (CEERT), reducing inefficient gas use could cut gas demand by one-fifth. In 2002 and 2003, an average gas-fired plant burned about 10 cubic feet of gas for every kilowatt-hour generated. Use could be cut by 20 percent—8 cubic feet\/kWh—if some power plants were upgraded or replaced, estimated Rich Ferguson, CEERT research director. According to the CEC, the savings could be even be higher. Aging power plants burn as much as 14,000 Btu\/kWh, while some of the new efficient plants burn 6,800 Btu\/kWh, said David Maul, CEC manager of natural gas. Maul added that plants? efficiency, or heat rate, should not be viewed in isolation; it should be considered along with how the facility is used and whether it supplies baseload or peaking power. Ferguson agreed, noting that is why he chose a higher average heat rate, 8,000 Btu\/kWh, for new equipment (his report is available at <a href="http:\/\/www.ceert.org"><font color="#0000FF">www.ceert.org<\/font><\/a>. ?What is tough is to see a plant [like Calpine?s Sutter facility] with potentially high efficiency if it ran full bore being used only a fraction of the time, decreasing its efficiency while the old dogs keep running,? Ferguson said. Like Sutter, many new plants are being run in a manner that reduces their efficiency. Much current demand is for peak power; thus, new baseload projects are being run as part peaker, part baseload, depending on need, said David Ashuckian, manager of the CEC?s Electricity Analysis Office.