Q1. The cost of heat from our local DE network is greater than the current deal we have with our regular energy provider. Why should we change?
Q2. There are several properties with the potential to connect to an existing or proposed DE network, but which cannot make the up-front capital costs stand up, particularly where any gain from lower bills for heating will be of benefit the tenant rather than the landlord. What alternative sources of funding are there?
Q3. What is the furthest distance over which heat can be exchanged?
A1. The cost of heat includes a number of items which all need to be considered when comparing the costs of heat from a network and producing that heat in a boiler.
Costs and other factors which should be taken into account in determining the current cost of heat are fuel, plant seasonal operating efficiency, boiler maintenance and periodic replacement of the boiler). In theory all of the costs are avoided under the district heating scenario and therefore should be included in the assessment. Overall, taking these factors into account heat from a local DE network should not be greater than your current costs.
It may also be appropriate to consider the value of the CO2 savings to the authority.
A2. With the LDA's support it is expected an additional £64 million will be made available through the JESSICA (Joint European Support for Sustainable Investment in City Areas) fund to unlock the development of decentralised energy in London.
Additional capital contributions might be available when considering the avoided costs of replacing plant either immediately or in the future. Note, this cost is noted above in relation to the heat price and will need to be considered as either a capital or operating cost, not both. The cost of replacing plant may need to take into account the requirements of the revised Building Regulations in relation to CO2 emissions.
A3. Technically there is no limit to how far heat can be distributed. The district heating system operating in Copenhagen is over 54km long. Well insulated pipe can yield heat losses of only 1°C per km which has a minimal impact on the system efficiency.
However, district heating pipe work can cost in excess of £1,000 per metre in the UK depending on the size of the pipe, the obstacles along the route, the ground conditions, etc. As such the extent of a distribution network will depend on whether it is financially viable to extend a route to connect a consumer – the building’s demand will need to be enough to generate sufficient revenue to pay back the capital cost of extending the scheme.
Heat losses from pre-insulated pipes are relatively constant, irrespective of the load, therefore the higher the heat density, i.e. the more useful heat that is sold, compared to the heat that is lost, the lower the overall percentage heat loss.