Combined heat and power project checklist

Here is information about whether you need planning permission for a CHP project and a project checklist that reviews all of the practical considerations.

Planning and regulatory requirements

Micro and Mini CHP

There are no planning requirements for micro and mini CHP as there are no external changes to buildings.

Packaged CHP

Many CHP packages are installed within existing buildings, and in these cases there is often no need for planning consent to be obtained. However, where the unit requires the installation of an external housing, the construction of a new building or a communal heating network then a planning application will have to be made, depending on the size and type of installation envisaged.

In situations where the installation will feed into an existing heat network, permission to connect needs to be obtained from the owner/operator of the scheme.

If a packaged CHP plant is connected to an industrial installation that is regulated under the new IPPC Directive (concerning integrated pollution prevention and control) procedures, then the CHP plant will probably need to be included in the scope of the IPPC authorisation from the regulator. Advice on the required information and procedure should be obtained from the appropriate regulator, usually the Environment Agency.

Large industrial and district heating CHP

Planning consent is required for large scale CHP. Applications for plants with capacities less than 50MWe need to be made to the local planning authority.

Applications for dedicated biomass plants with capacities greater than 50MWe are not determined by the local planning process. They need to obtain development consent from the Secretary of State. The application needs to be submitted to the Infrastructure Planning Commission (at a future date this will be replaced by the Major Infrastructure Planning Unit).

The Pollution Prevention and Control Regulations (part of the Environmental Permitting (EP) Regulations) apply to fuel-burning installations that have a fuel input rating of more than 20 MW.

All scales

Space requirements Space requirements depend on fuel source. Bulky fuels such as biomass would require more space for storage.
There must be sufficient access for maintenance purposes and to house any auxiliary equipment.
The location should allow space for storing additional fuel (e.g. additional boiler backup fuel), lubricants and other items necessary for effective plant operation.
Siting of building level or large scale CHP within a community needs to allow for the appropriate installation of a flue. This needs to be above the height of the tallest building in the development.
For large scale CHP the actual footprint of the plant depends on the generating capacity and technology selected (e.g. a 40MW plant would require approximately 4,000m2).
Noise Although most CHP engines and gas turbines are supplied with acoustic enclosures, noise is produced by the plant and its auxiliary equipment. Since the plant may operate almost continuously, where possible its location should minimise the impact of the noise.
Electrical grid connection For micro/mini and packaged CHP, the "Fit and Inform" electricity grid connection regulations apply. These require that the distribution network operator (DNO) is informed of the connection, but it is not necessary to request permission. There are standards that the system needs to meet before it is connected. Qualified installers will be aware of these requirements.
For large scale CHP, an application needs to be made to the DNO for grid connection. The site needs to be located close to the grid connection point to keep cabling costs down. Overhead line costs around £20,000 - £35,000 per kilometre and buried cabling can cost over ten times this.
Heat demand Heat demand in homes and commercial properties tends to be "spikey" with peak demand occurring at certain times of the day and the year.
For packaged or large scale CHP, heat demand can be "smoothed" by ensuring that a mix of building types are connected to the community heating network. For example, ensuring that there are anchor loads connected to the network such as hospitals, hotels, and prisons. These anchor loads have a large and steady demand for energy over 24 hours.
As a general rule of thumb for large scale CHP (particularly in a communal heating setting), heat densities of 3,000kW per square kilometre per annum are required to make CHP viable.
For more information about heat demand see:
Opportunities for combined heat and power
Future proofing Future changes in heat demand and technological developments need to be accommodated. For example, for existing housing, are there plans for fitting insulation and double glazing to improve home energy efficiency and reduce heat demand?
Practical ways in which systems can be future proofed include ensuring:
  • there is space for additional plant to cover future expansion of the network
  • that the plant is housed in a way that will allow plant replacement and possibly the installation of new technologies, such as fuel cells or biomass CHP
  • that the pipework is sized to enable future expansion of the network.
Energy efficiency The energy efficiency requirements of the Building Regulations have become more stringent over time. As this continues, new buildings will have relatively low heat. This presents a challenge for the installation of CHP because new buildings may not present enough heat demand to make CHP systems viable.
This may be resolved by connecting to the network a mix of uses and adjacent existing buildings that have poorer insulation, and therefore greater energy demand. However, it is important to make sure that insulating existing buildings where feasible is not avoided just to make a better base for CHP.
Fuel supply It is important to make sure that the CHP scheme has access to a steady, secure supply of the chosen fuel, particularly if this fuel is not currently supplied to the site.
For example, if switching from oil to natural gas, check that there's a natural gas network available. Or, if planning to use biomass, check that there is a sustainable and secure supplier who will deliver to the site for a reasonable price.

Micro and mini CHP

Space requirements Micro/mini CHP units will normally fit in the space occupied by an existing boiler.
Heat demand To overcome changes in heat demand systems at this scale are installed along with thermal storage (e.g. hot water tanks). To address heat demand, this scale is usually pre-sized on the basis of average heat consumption in homes.
Boiler replacement If boilers are scheduled for replacement in the short term, this is an ideal time to consider conversion to micro/mini CHP. This would help to offset some of the capital cost of the CHP.
If the existing boiler has been recently installed (within the last 3 to 5 years), it may be less economically viable to install CHP for the following reasons:
  • Modern condensing boilers are more efficient than the micro-CHP units currently available (although they do not have the advantage of electricity production). Therefore, the user will not see significant energy bill savings when switching.
  • Payback periods for replacing existing boilers with new condensing boilers are between 8 to 10 years. By replacing a recently installed boiler, some of the investment made on the boiler is lost.

Building level and Large scale CHP including district heating

Space requirements Packaged CHP will fit into the existing boiler room in the case of retrofitting. However, it is necessary to ensure that there is room for additional equipment and pipework. In the case of new build projects, site layout needs to incorporate approximately 40m2 for the boiler house (based on a 60kW system). Packaged CHP can also come in a shipping container.
Heat demand To overcome changes in heat demand systems at this scale are "smoothed" (see heat demand at all scales). To address heat demand, systems are usually pre-sized on the basis of average heat consumption in commercial and public buildings.
Existing energy contracts If there are energy contracts with an energy supplier (particularly those that require commitment for the long-term) these may affect the financial viability of a CHP system. It would be difficult to recoup the capital investment (in terms of energy savings) made in installing CHP. It would be more beneficial to wait until the end of the contract term.
Infrastructure The CHP plant needs to be located in a position from which the recovered heat can be supplied to the end user. To maximise the benefits, you need to consider the potential for connecting buildings located outside the site boundary (particularly in the case of packaged CHP). Technically, heat can be transferred over very long distances, although consideration need to be given to the point highlighted under "proximity to end user" below.
Installing a CHP plant to serve a number of existing buildings is likely to be challenging due to the need for a distribution network. Some issues to consider include obtaining wayleaves as well as the cost and disruption for road and building users.
See the district heating technical issues section for more information:
link to be added when live
Proximity to end user Proximity to the end user has two main implications - cost and heat loss:
  • Installation of pipework costs around £700 to £1,000 per meter. It is therefore necessary to minimise the length of pipework required by locating district heating CHP close to the end user.
  • Heat losses occur as the heated water moves along the pipework. Reducing distance from heat source to end user also helps reduce these losses which can be as high as 10 per cent, but much lower if well designed.



1 May 2012

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