Given the relatively long product life cycles in this industry, tracking the progress of a new gas turbine from its design through testing and first installation takes endurance. But in the case of General Electric's LMS100, following the maturation is worth it because the machine's many innovations reflect significant changes in the dispatching flexibility required of today's gas-fired peaking plants.
One feature of the LMS that immediately gets your attention is the ability to synchronize its entire 100-MW output from a cold start in only 10 minutes. Another is its very low heat rate of about 7,500 Btu/kWh, which makes the unit suitable for providing spinning reserve without generating excessive pollution during start-up. Need to reduce power? That's no problem, because the heat rate remains fairly constant as output is ratcheted down toward half-load—every resource planner's dream.
GE Power Systems added the LMS100 to its stable of gas turbine-generators late in 2003 to address growing demand for efficient, mid-range (80 MW to 160 MW) peaking capacity. GE answered the need by carefully mixing and matching the best parts of its aeroderivative and industrial machines.
New block on the skids
In the March 2004 issue of POWER, three months after the introduction of the LM100 (Figure 1), we described it as follows: "[Its] low-pressure (LP) compressor has exactly the same parts as the first six sections of the heavy-duty LP compressor in the MS6001FA power generation workhorse. But the technologies used in its core—the high-pressure (HP) compressor, combustor, and HP turbine—first proved themselves in GE's LM aeroderivative products descended from the CF6-class aircraft engine. But not everything in the LMS is 'something borrowed.' Its two-stage intermediate-pressure (IP) turbine and five-stage power turbine are based on the latest GE aeroderivative technology, and the latter was designed specifically for the LMS100."
1. Mr. Big. The LMS100 is GE's first aeroderivative gas turbine rated higher than 100 MW. Source: General Electric
It would be a huge oversimplification, however, to consider the LMS100 the result of checking off parts lists, Chinese menu–style. For example, the systems engineering needed to integrate disparate turbine components with off-engine intercooling technology was immense. But in this case, the end justified the means: a nimble gas turbine able to instantly respond to the needs of a dispatcher with a thermal efficiency far exceeding that of a typical steam plant. Even at 50% turndown, the LMS100 is still nearly 40% efficient—better than most gas turbines can achieve at full power (Table 1).
Table 1. The basic specs of the GE LMS100. Source: GE Power Systems
Furthermore, the LMS100's low hot-day lapse rate eliminates the need for inlet conditioning and lowers the system's operating and ancillary capital costs. Whatever your product's performance and environmental requirements, there seems to be a configuration of the LMS100 to satisfy them (Table 2).
Table 2. Performance specs of a 60-Hz LMS100-based system, measured at its generator terminals at ISO conditions (59F, 60% relative humidity, sea level). Source: GE Power Systems
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