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Renewable energy and combined heat and power (CHP)

Find out about renewable energy technologies and download guidance on renewable energy generation, combined heat and power (CHP), and ground- and air-source heat pumps.

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Renewable energy sources guide

Published January 2018

Renewable energy refers to energy that occurs naturally and repeatedly in the environment. Therefore, it does not release any net greenhouse gases into the atmosphere. Using renewable energy sources can offer a wide range of benefits to your business:

  • lower energy bills
  • energy price stability
  • security of energy
  • 'green' credentials
  • possibility of selling electricity back to the grid at a premium

This 21-page Renewable energy sources guide introduces the main sources of renewable energy and helps readers to assess whether using renewable technologies are a viable option for their business.

Guide contents:

  • Renewable energy overview
  • Renewable energy opportunities
    • How to select a renewable energy technology
    • Wind power
    • Solar electricity (photovoltaics)
    • Solar water heating
    • Biomass
    • Anaerobic digestion
    • Ground-source heat pumps
    • Air-source heat pumps
    • Small-scale hydro-electric power
  • Renewable energy funding and grants
  • Useful websites
  • Next steps to take when assessing the renewable energy options
  • Glossary

Publication date January 2018; Publication code CTV010v3

Information in this report was correct at the time of publication

Download the guide:

Renewable electricity generation

  1. Wind power (small scale wind energy)

    Wind turbines are used to produce electricity. They are attached to outside of buildings - require a structural survey and planning permission.
  2. Solar electricity (photovoltaics)

    Solar photo voltaic (solar PV) panels or cells convert sunlight into electricity.  They are attached to outside of buildings - require a structural survey and may require planning permission.
  3. Small-scale hydro-electric power

    An immersed turbine uses flowing water to produce electricity. This technology is highly site-specific. It requires a near body of water that is flowing and has a drop in level that can be exploited.


Renewable heat generation

  1. Solar water heating (solar thermal)

    Uses energy from the sun to heats water up to 55-65ºC. Systems should be roof-mounted and ideally integrated into your current immersion-heated, hot-water system.
  2. Biomass

    Generating power by burning organic material, such as wood, straw, dedicated energy crops, sewage sludge and animal litter. Lots of space is required for the boiler and storage of fuel.  Site access is also important for deliveries of fuel.
  3. Anaerobic Digestion (AD)*

    Bacteria break down organic material in the absence of oxygen, producing a combustible methane-rich biogas.  Requires access to large amounts of high-strength liquid organic wastes. Planning permissions will be required and you should consult a specialist about odour control.

    *Note: output can be for heating, combined heat and power (CHP) or fuel for transport.
  4. Ground-source heat pumps (GSHPs)**

    Using naturally-occurring underground low-level heat.  Most suitable for 'new builds' with appropriate geological features.
  5. Air-source heat pumps (ASHPs)**

    Converting low-level heat, occurring naturally in the air, into high-grade heat.  System must be attached to outside of buildings - planning permission may be required

**Note: Ground- and Air- source heat pumps are not completely 'renewable' as they require electricity to drive their pumps or compressors.

Combined heat and power (CHP)

Combined Heat and Power (CHP) is the on-site generation of electricity and the use of the heat that is produced as a by-product.

Further guidance


Publication date: 2010 - 2012
Information in these guides was correct at the time of publication


The following publications are available for free download:

For information on Feed-in Tariffs (FITs), please read our FAQ, or consult the UK government FITs page.

For the latest news and information on the Renewable Heat incentive (RHI), please consult the UK government RHI page

The National Biofuel Supplier Database can be found at:

Visit the MCS (Microgeneration Certification Scheme) website for details on how to become MCS certificated. If you are already MCS certificated then you will be able to find further useful resources on the MCS site.


Support for your organisation

If your business is looking to install renewable energy generation, see our services to find out how we can help.  This includes:


Energy efficiency support

The Carbon Trust Green Business Fund offers energy efficiency support and energy assessments for small and medium-sized businesses in England, Scotland and Wales.

If you'd like to improve energy efficiency of your organisation, see our services for small to medium enterprises to find out how we can help.

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