Another advantage of these power plants is that the natural gas they run on is less carbon dioxide-intense than other fossil fuels. This means that the generators in combined-cycle plants are one of the key power generating technologies in the battle against climate change.

In December 2007, Siemens first ignited a new 375-megawatt gas turbine – the most powerful yet most eco-friendly unit of its kind in the world – at the Irsching 4 power plant in Bavaria.

The Irsching turbine’s improved efficiency means it not only consumes less fuel per generated kilowatt hour, it also emits less nitrogen oxide (fewer than 15 parts per million) and carbon dioxide. When the turbine goes into combined cycle operation, it is expected to set a new world efficiency record of more than 60 percent and, compared to current combined-cycle plants with the same capacity, it will emit 45,000 tons less carbon dioxide a year.

Due to the significant advantages offered by the combined-cycle process, the technology will be adapted to fuels other than gas, including coal, biomass and refinery residue. Integrated gasification combined-cycle power plants (IGCC) in particular look to be a promising way forward.