Energy efficiency - Cogeneration
What is 'cogeneration'?
Cogeneration is the production of two useful forms of energy, such as high-temperature heat and electricity, from the same process. For example, while boiling water to generate electricity, the low-pressure unused steam can be sold for industrial processes or space heating.
Cogeneration is a high-efficiency energy system that produces either electricity (or mechanical power) and valuable heat from a single fuel source. For example, a hospital cogeneration plant could produce some of the power and all the hot water needed for its laundry and hot water system from the waste heat it generates. Similarly, office buildings can produce power for electricity and air conditioning from the waste heat generated by its air conditioning engines.
Cogeneration is sometimes known as 'combined heat and power', or CHP. It offers major economic and environmental benefits because it turns otherwise wasted heat into a useful energy source. This greater efficiency means carbon dioxide emissions are cut by up to two-thirds when compared with conventional coal-fired power stations.
Businesses, government agencies and facilities most likely to benefit from cogeneration are those that use large quantities of hot water, heat, steam or chilling such as hospitals, large maintenance facilities, aquatic centres and laundries. Others that could benefit from cogeneration include hotels; office buildings; food and beverage processors; chemicals and plastics producers; pulp, paper and fibreboard manufacturers; metals processors; textile producers; shopping centres; universities and TAFEs.
Cogeneration is a proven and reliable technology currently operating at over 100 sites across Australia.
What are the benefits of cogeneration?
Cogeneration can significantly reduce energy costs and greenhouse gas emissions, typically by up to two-thirds. Local air quality benefits can also be achieved through the replacement of older coal-fired boilers. In addition to reducing operating costs, cogeneration also increases resource utilisation.
What is the potential for cogeneration in NSW?
There are a number of opportunities for small-scale, gas-fired cogeneration in NSW. There is also significant potential for cogeneration plants fired by other fuels, including biomass (for example plant waste from sugar or cotton harvesting) or biogas (for example methane produced by sewage works or piggeries); 200 MW of gas-fired cogeneration alone could reduce the state's greenhouse gas emissions by 800,000 tonnes per year.
Here is a collection of sites for organisations interested in cogeneration:
- The Clean Energy Council (CEC)
Includes over 400 businesses covering a quarter of Australia's total electricity production including gas, wind, hydro and bioenergy. Also includes a range of businesses in the low-emission energy and energy efficiency sectors, including solar PV, solar hot water, biomass, geothermal and cogeneration.
- COGEN Europe
A large and comprehensive organisation promoting cogeneration in Europe.
- UK Combined Heat and Power Association (CHPA)
The association supporting the rapidly increasing use of combined heat and power in the UK.
- US Combined Heat and Power Association (USCHPA)
An association that aims to create an environment in which combined heat and power is fostered as a major energy source in the United States.
- University of Rochester District Energy Library
A great source of information on many kinds of energy, but particularly cogeneration.
- World Alliance for Decentralized Energy
An industry federation working to promote sustainable economic development and energy modernisation through the use of cogeneration.
Cogeneration case studies and project summaries
Two 760 kilowatt gas-fired generators have been installed to provide electricity for general use at Macquarie University. The waste heat powers an absorption chiller for air conditioning, with chilled water storage to level out peak air conditioning loads, and supplies heat for university use. This is the first system in Australia to use combined power, heat and cooling with chilled water storage. The $6.7 million project is saving 5400 tonnes of carbon dioxide per year and will save the university an incredible $20 million in energy costs over 23 years. Download the case study (PDF 3.5MB). This is a SEDA case study.
Broadwater and Condong Sugar Mill
Australia's largest renewable baseload energy project, the construction of two 30 MW cogeneration facilities at the sugar mills in Condong and in Broadwater is reaching completion. This has been a joint venture between Delta Electricity and the NSW Sugar Milling Co-operative, known as Sunshine Electricity.
Newcastle University microturbine
The University of Newcastle has successfully implemented Australia's first commercial application of a gas-powered microturbine to help realise both financial and environmental benefits. The 30 kW natural gas-powered microturbine is at the heart of the university's Medical Sciences building cogeneration unit. The plant provides some of the power for the Medical Sciences building air-conditioning system, while the wasted heat is captured and used to heat water to feed the domestic hot water system, as well as to provide heating for the air-conditioning system. Download the case study (PDF 318KB). This is a SEDA case study.