DEFINITION - What is Decentralised Cogeneration?

In a combined heat and power (CHP) plant, the energy from a fuel is used to generate both electricity and heat. Thermodynamically, the heat is recovered from the waste heat of the electricity generation process, resulting in a higher overall energy efficiency than can be achieved if the processes are operated separately.

Decentralised cogeneration, or CHP, systems are targeted at the residential, commercial and small industrial markets.

In the commercial and industrial markets, the cogeneration systems could use either gas turbines or internal combustion engines. In the residential market the primary technology is natural gas or fuel oil fired internal combustion engines, as gas turbines are not a good match for typical residential electricity demand levels.

Wood or biomass fired systems are also available but mostly at larger capacity levels that are better suited for centralised deployment. Other technologies such as Stirling engines are also available though less common.

CONSTRAINTS - What are the key barriers facing Decentralised Cogeneration deployment?

• Decentralised cogeneration systems need to be connected to the electricity grid to be more reliable and this can be challenging from a technical and regulatory viewpoint.

• The capital cost of cogeneration systems is significantly higher than the one of more conventional technologies.

• A significant fraction of both the electricity and heat output of a distributed CHP system must be used to make the system cost effective. It can often be challenging to simultaneously match both loads in small distributed applications.