When we think of energy efficiency, we often think of making homes and businesses more efficient in their use of energy. Combined heat and power (CHP) confronts efficiency from the other end of the chain, looking at how to make use of the heat that conventional power stations produce as a waste product.
Phil Else explains how CHP works and why it is a technology that’s ideally suited to small-scale local initiatives to produce power and heat for farms and communities.
So, what is CHP?
Not something that seems to be at the fore front of domestic heating issues, CHP systems are rapidly becoming an important alternative form of energy that small scale farmers are using to generate additional income and make use of farm land that they are prevented from using due to the fallow-land subsidies to reduce the ‘food mountain’.
The basics of a CHP system are:
- Electricity is generated using a gas or diesel powered engine.
- Such an engine, just like your car engine, generates a phenomenal amount of heat that is ordinarily vented to the atmosphere, however this heat can be recycled to run domestic or commercial heating systems, generate steam or provide heat to greenhouses and similar processes.
- The engines can be set to run off bio-diesel or bio-gas, which can be created from the waste products of greenhouses, such as vegetable and fruit leaves and animal waste.
The advantages of a CHP system to the local farmers who are investing in them are:
- They can sell the electricity generated to the National Grid (on currently decreasing tariffs) and they can also use it to power their homes and farms.
- The heat produced warms their home and greenhouses
- The engines are fuelled by gas generated from vegetable waste product.
How can CHP systems help support Green Party values?
- The engines can be used to provide electricity to local homes, businesses and infrastructure (eg: street lighting).
- Being relatively small (about the size of a road transport container) they can be sited close to schools, council offices, care homes, market places, hospitals and housing estates.
- Using locally sourced vegetable and animal waste they can be powered using carbon-neutral fuel (fuel that has it’s carbon emission equal to it’s previous carbon absorption)
- Sited and used locally the systems have an intrinsic value to the community and can reduce community or residential power and fuel bills.
- A council owned system can be used to benefit local charities and social housing schemes by providing free or subsidised heat and power.
What does it cost?
A small engine (400 kW – enough to power a large clinic or small school) costs approximately £350,000 plus a maintenance contract. If used to feed the national grid the pay-back period using locally generated bio-gas is 7-8 years, or if used to provide heat and power to social housing has a much greater intrinsic value.
Find out about CHP schemes
Phil Else is a lecturer at Trafford College, Greater Manchester. Having been involved in the plumbing, heating, ventilation and air-conditioning industry for many years and has turned his hand to teaching the subjects related to the building services industry. Green ideas and technologies are firmly linked with providing sustainable buildings and protecting the environment, and Phil tries to ensure that green issues are raised and considered as part of any on-going design and at construction project inception. Phil joined the Green Party in 2014.