Combined Cycle Operation

Combined Cycle Operation Basics Explained

A combined cycle operation power plant is one that consists of gas turbine generator units, steam generators, a steam turbine and a generator with a feedwater system and a condenser. Combined cycle power plants are being constructed all over the world these days due to the fact that they offer a high degree of thermal efficiency. Some plants in operation today consist of as much as fifty-two percent thermal efficiency, making this type of plant increasingly popular.

The reasons these plants are so efficient is the fact that they capture the heat exhaust expended by the gas turbine to use in the Rankine cycle. Otherwise the heat from the exhaust gases would be lost in the air such as in an open cycle gas turbine.

Another main reason that a combined cycle operation power plant is so popular today is the fact that this type of facility can be built rather quickly compared to a conventional steam plant. The most common fuel used by a combined cycle gas turbine power plant is natural gas.

Some gas turbine power stations in the world have been converted into combined cycle operation power plants for costs exceeding $100 million such as what was done to a plant located south of Teheran, Iran in the mid 1990s. That particular venture took a total of just under two years to complete and was financed by the World Bank. The plant's output was boosted by a full 50% once the work was done. Today's worldwide energy market puts many demands on power generation technology which includes high thermal efficiency, low costs, quick installation and environmental compliance. Combined cycle operation power plants meet these demands and actually surpass them by taking power plant performance to new levels.

A combined cycle operation power plant's efficiency is far greater than either the gas turbine or the steam turbine efficiencies. This type of plant is essentially an electrical power facility which uses a gas and a steam turbine in combination to achieve the heightened efficiency that what is possible when working independently of one another. Rising fuel prices and growing demands for electricity are putting much more demand on power producers to generate electricity in the most efficient manner possible. The combined cycle plants can produce high outputs of power at rates of around fifty-five percent, making them all the more attractive. This is leading to more and more simple cycle plants being converted into the much more efficient combined cycle facilities.