| Benefits of simple cycle natural gas | Concerns about simple cycle natural gas |
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| Benefits of combined cycle natural gas | Concerns about combined cycle natural gas |
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Simple cycle gas turbines require a smaller capital investment than coal or even combined cycle natural gas plants, and can be designed to generate small or large amounts of power. The construction process is significantly shorter compared to base load power plants.
Another main advantage is the turbine's ability to be turned on and off within minutes, supplying power during peak demand (such as mornings and supper time). A typical large simple cycle gas turbine may produce 50 to 300 MW of power.
The exhaust air from a combustion turbine is typically very hot (450-600 °C) and contains useful energy. Large-scale systems will often add a cycle that converts the heat of the combustion turbine exhaust to create steam, which can be used in a secondary steam turbine generator. The total conversion efficiency of a combined cycle (gas turbine and steam cycle) can be higher than that of either system individually. A typical large combined cycle combustion turbine facility would be 10-15 per cent more efficient than simple cycle gas turbines.
Simple Cycle Gas Turbines
Simple Cycle Gas Turbines (SCGT) generate electricity by turning the turbine using hot gas produced during the combustion process. This type of electricity generation is best for meeting peak loads, such as hotter periods in the summer or colder periods in the winter.
There are many advantages to generating electricity with SCGTs:
- SCGTs produce up to 50 per cent less CO2 per megawatt hour than conventional coal-fired generation.
- SCGTs assist with the integration of additional wind power into the electricity system.
- Unlike larger base-load units (units that are in operation at all times), these turbines can be turned on and off as needed and can be put into operation quickly during peak times when electricity demand is greatest.
- SCGTs are relatively easy to install, which reduces construction costs.
- SCGTs are flexible with respect to where they can be installed, helping to reduce the need for new transmission lines.
- Emissions of sulphur dioxide, particulates and mercury are near-zero. With modern control strategies, the nitrogen oxide emissions will also be reduced.
