Sometimes Small Things Are A Big Deal

Gas-fired combined cycle powerplants have been around for decades.  In fact, they were almost ubiquitous in the 1990s, sprouting up across America like weeds. 

The only reason they lost favor in the early 2000s is that, because so many were built, natural gas prices spiked from about $2/mmBtu to over $10/mmBtu, making the variable cost of these powerplants too high to economically run as anticipated — and ruining the finances of many independent power producers such as Dynegy (NYSE: DYN) and Calpine (NYSE: CPN).

Of course, with the recent boom in shale gas, coupled with the likely pressures to retire old coal-fired powerplants due to tightening mercury emissions limits, great expectations are once again being heaped on combined cycles to increasingly power the U.S. utility grid.

Now comes word from Technology Review that GE (NYSE: GE) is refining its standard combined cycle design to start-up and spin-up to full power much more quickly, while achieving considerably higher combustion efficiency (61%!).  These improvements are being enabled by advanced materials (nickel-based super alloys) and more sophisticated controls systems.

The benefits of these seemingly incremental and innocuous changes are very important.  The faster “ramp-rate” is especially critical to enable grid operators to better cope with the variability in output from solar and wind energy sources — which, of course, naturally goes up and down in fairly rapid and often unpredictable patterns.  The title of the article sums it up nicely:  “A Gas Power Plant to Make Renewables More Practical”.

As Jim Watson of the University of Sussex says succinctly in the article, “it’s not a low-carbon technology, but it could be part of a low-carbon system.”  Put another way, every little bit helps, and we don’t have to wait for near-free solar energy and energy storage to have a big impact. 

It’s a pity that North America will not be the initial market for roll-out when introduced later this decade.  Another instance in which the U.S. will be a late beneficiary of cleantech innovation.

1 reply
  1. Bilsko
    Bilsko says:

    Be careful with the terminology – its definitely not 61% combustion efficiency. It's 61% overall efficiency – you have to include the "combined" part of 'combined cycle'

    Combustion efficinecy for any aero-derivative gas turbine won't do much better than mid-thirties. Take the exhaust gases, generate steam, and run that through a steam turbine and you can eak out another 30% efficiency. Total, 61%

    The efficiency figures in and of themselves aren't that impressive – its the combination of efficinecy and ramp-up times (only a couple of minutes IIRC) that makes these GE models notable.

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