This article was taken from the March 2012 issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.
The General Electric (GE)
FlexAero LM6000-PH is a lightweight, natural-gas turbine. It can run without water, so one FlexAero can save up to 98 million litres a year compared to a water-cooled equivalent. Essentially a jet engine -- its technology is derived from GE's turbofan designs -- the FlexAero can power up or down in less than ten minutes. Its flexiblility enables it to operate from less reliable power supplies such as wind and solar. Start the engines...
How it works
Highly pressurised gases are used to spin a turbine. After air is compressed and combined with fuel, the mixture is ignited to force an expanding mass of air through turbine blades at high speed. The blades spin around the drive shaft, driving a generator to create electricity.
1. Low-pressure compressor
A number of rotating compressor blades alternate with stationary vanes to push air through 14 stages of compression. Air in the low-pressure compressor is squeezed to 32 times that of Earth's atmospheric pressure.
2. Island
mode Most industrial gas turbines -- which are larger and heavier than this one -- require power from the grid to get started. The FlexAero can use batteries to initiate a hydraulic starter system, making it well suited for power generation in remote areas that may lack grid access.
3. High-pressure compressor
The heart of the turbine: pressures and temperatures are at their highest here -- around 1,300 degrees centigrade. The turbine blades spin at 10,000rpm, turning the generator drive shaft.
GE-proprietary alloys have been developed to withstand the extreme heat.
4. Dry low-emissions system
Conventional turbines use large amounts of water (as steam) to control flame temperature, and so reduce heat and nitrogen oxide (NOx) emissions. The FlexAero does away with water by mixing air and fuel before ignition. Multiple fuel nozzles also aid temperature control.
5. Combustion chamber
Compressed air is funnelled through the combustion chamber, where it mixes with natural gas fuel and ignites. The mixture expands under even higher temperatures before entering the high-pressure turbine.
6. Exhaust-air
diffuser Exhaust air is funnelled to a heat-recovery system, generating steam to drive a turbine. Combining steam and gas turbines in a "combined cycle" configuration generates electricity more efficiently than either would alone: typically 54 per cent efficiency, against 42 per cent independently.
Get a closer look at the turbine in our high-res gallery.
This article was originally published by WIRED UK
