Natural Gas in Your Business | Co-generation

Co-generation involves the simultaneous generation of electrical or mechanical energy and thermal energy from a single fuel source, usually Natural Gas.

An internal combustion engine or a gas turbine burns Natural Gas to generate electricity or produce mechanical energy, for example for an air conditioning compressor. Heat from the water jacket and exhaust of an internal combustion engine, or the exhaust gases from a gas turbine, are recovered and used to generate hot water or steam.

This can be used for heating a building, for generating chilled water from an absorption chiller or for any other industrial process able to utilise heat in this form.

Electrical Generation

The process of co-generation produces electricity at an efficiency of around 30% and can be used in the following ways:

  • Total electrical supply - balance fed into the power grid
  • Peak shaving - used to reduce peak load where Peak Demand Tariff exists, can also provide emergency electrical power
  • Generate power for specific plant - also reduces peak demand, and can provide emergency electrical power.

Internal Combustion Engine

Up to about 50% of the energy from the prime fuel can be recovered from the water jacket and exhaust as thermal energy can be used for:

  • The production of low pressure steam
  • Hot water
  • Production of chilled water from an absorption chiller
  • Space heating - using either hot water or steam
  • Any industrial process able to use this grade of heat.

Gas Turbines

Gas Turbines produce dry exhaust gases at a temperature of approximately 500ºC. These gases can be used directly in drying ovens or in waste heat boilers to produce steam or hot water, which can then be used in the same sort of applications as the internal combustion engine, (see above.)

Efficiency

The production of electricity and use of heat, which would otherwise be wasted, generates efficiencies as high as 75-80%. Compare this to a centrally generated grid electrical efficiency of about 30%. An added environmental benefit is the considerable reduction of carbon dioxide emissions.

Most Economical

Where there is a balanced demand for electricity (or shaft power) and thermal energy, Natural Gas fuelled co-generation is one of the most economical methods of generating electricity currently available.