Explaining the Types of CHP Systems
CHP (Combined Heat and Power) is the single process of generating useful heat and electricity, through a process called cogeneration. Throughout this article we explore the different types of CHP systems used throughout the UK today. Below is a small list of the different systems, click the links to navigate to each individual section.
Industrial CHP is generally the largest of the CHP systems, ranging from small systems generating a few MWe to large power plants, similar to conventional power stations you see plotted around the countryside. Much like traditional power plants CHP plants generate electricity, but further capture usable heat, which is usually lost / wasted through traditional power plants. These large CHP power plants can provide heating and electricity to local communities or help large companies run their factories.
A CHP plant can reach an overall efficiency of 80 percent whereas a traditional coal powered plant would have an efficiency of around 40 percent.
Packaged CHP and mini-CHP are smaller CHP systems designed to provide the heating requirements of a small building such as office blocks, factories, leisure centres or supermarkets. These systems are usually supplied as complete units that can be easily connected to a buildings current electrical and heating system. Various sizes of packaged CHP can be installed ranging from 50 KWe to 1 MWe.
Current technologies are usually combustion engines but other technologies, such as CHP fuel cells and micro gas turbines are in development.
Sainsbury’s have used packaged CHP at some of their supermarkets.
Micro CHP systems are designed for households to generate heating/electricty and can be used to replace the household’s current boiler. Micro CHP systems are primarily used to provide space heating and water heating requirements for the average home, while also generating electricity. Micro CHP can be seen as your normal gas boiler with the added extra of generating electricity.
Micro CHP generates its energy from an energy source while a combustion engine, Stirling engine or fuel cell generates the electricity. Once a CHP system has fully warmed up it can power all the lighting and appliances in a typical home. while any electrical generated not used can be exported back to the national grid. Currently, under the Feed-In Tariff 10p per unit of electricity generated and an additional 3p per unit exported can be achieved.
Some Benefits of Micro-CHP
- Unlike other renewable energy technologies micro CHP does not rely on building orientation or weather conditions to generate electricity.
- Generates electricity at times of peak electrical demand in the home
- Maximises greener and cheaper on-site use, helping to alleviate fuel poverty
- Reduces reliance on grid electricity
- No planning permission required
- Reduces carbon emissions
CCHP uses tri-generation unlike normal CHP which uses the scheme cogeneration to generate heat and electricity. This means that the system can provide cooling and heating from the same energy source. To achieve this, absorption chillers are attached to the CHP system and cools excess heat to provide air conditioning. This can be particularly useful for large buildings that require a large amount of air conditioning in the summer and heating in the winter.
MediaCityUK is a good example of a CCHP system and further information can be found at the CHP association website.