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Gas turbine OEMs are targeting the renewable energy market with machines that can respond quickly to match the total load demand of fluctuating renewable power while maintaining grid stability. GE Energy’s LMS100, in particular, is finding broad application in areas such as
, which boast high renewable portfolio standards.
Nineteen of the first 54 LMS100s have been sold to customers in
, which has issued a goal requiring that 33% of electricity come from renewable sources by 2020. “Gas-fired generation is our only means right now, until storage and demand response have matured, to compensate for the fluctuations of wind and solar power,” says California Independent System Operator (CAISO) spokesperson Stephanie McCorkle.
The LMS100 is said to provide greater capacity than aeroderivatives but faster start times than frames. It starts with the low-pressure compressor from the Frame 6FA IGT, runs the air through an intercooler, and then into a supercore (HP compressor, high-pressure turbine and intermediate-pressure turbine) based on the LM6000. Using the intercooler to lower the temperature of the air going to the high-pressure compressor reduces the work of compression, resulting in a 42:1 pressure ratio and increasing the flow mass to 460 lb/sec.
To reduce NOx emissions, LMS100s come with either water injection (the LMS100 PA) or dry low NOx DLE) combustors (the LMS100 PB), and both models produce a 25 ppm NOx emission. The LMS100 PA has 103 MW output and the PB 99 MW (100 MW for the 50 Hz version). The PB has a lower heat rate – 7,695 Btu/kWh compared with 7,815 Btu/kWh for the PA. All LMS100 models offer a 44% efficiency rate, ten-minute start times and 50 MW per minute ramp rates, making themsuitable for peaking and load following operations. They also meet the needs for base load power generation, giving power producers greater flexibility in their system design.
Technology that lets you start, synchronize and meet full load in short time frames modifies spinning reserve requirements, says Joseph Camean, VP and Director of Power and Utility Engineering Services for Van Zelm, Heywork and Shadford. Spinning reserve markets typically require that the turbines be fired up and able to synchronize with the grid within ten minutes. With the LMS100, however, no spinning is required, since they can black start and synchronize within that time frame.
Connectiv Energy, for example, a subsidiary of Pepco Holdings, which owns 20 generating stations in five
Middle Atlantic States
, has started specifying LMS100s so it can participate in PJM Interconnection’s voltage support and reserve markets. PJM is a regional transmission organization that coordinates the movement of wholesale electricity in several states. Power markets require turbine owners to have greater flexibility, providing back start, spinning reserve, base load and voltage support when needed. One way to achieve this flexibility is with a synchronous clutch. The clutch allows the turbine to bring the generator up to speed and then disconnect so the generator stays connected to the grid, operating as a synchronous condenser to provide voltage support while the turbine can shut down until it is needed to provide peaking power.
(More in the 2013 Turbomachinery Handbook)