Martin's job is immeasurably more difficult because he is running his pipework under existing streets and pavements and reinstatement costs mean that the actual cost of connecting a house to the scheme is between £2000 and £3000, though this cost is being met entirely by the Islands Council. The residents are offered free connection and hot water costing 1.75p/kWh, roughly equivalent to mainland gas prices, though the additional annual standing charge of £100 is higher. The Islands Council is paying for the connection and is offering some additional grants to convert from electric heating to warm water radiators but beyond that the scheme is self financing.
UK community heating schemes have been installed in the social housing sector. Shetland is the first substantial scheme to be taken up in the private sector and the initial indications are that they take up rate is exceeding expectations. "I have forty homes already connected" says Martin "and around another 150 earmarked for connection during 1999. That's getting on for 7% of the 3000 homes in Lerwick. We estimate that eventually we'll have nearly half the population connected although this will take a number of years as people get around to replacing their existing heating systems."
Back in fashion
Can the rest of the UK learn anything from Lerwick's scheme? After decades of neglect, community heating is coming back into fashion, helped by new techniques for generating electricity as well as hot water, so called Combined Heat and Power plants or CHP. The driver behind this is the capability offered by these CHP plants to generate green electricity at around 1.5p/kWh, about a quarter of the amount charged by the RECs on their peak time tariffs.
Around 70 residential CHP schemes have been installed around the UK, some as refurbishments of older district heating schemes, others new builds, to date all in the social housing sector. One such scheme just being completed is a development of 63 sheltered flats and some offices on a site at Scott Street in Perth being built by two housing associations, Perthshire and Servite. The CHP unit is by Nedario UK and it is anticipated to run for 16 hours a day and to provide just over 50% of the entire electricity needed to power the development, at a cost of 1.5p/unit instead of the going rate of over 6p/unit. Waste heat is also taken from the system and contributes about 5% of the energy needed to supply hot water around the development, the remainder being provided by a more conventional district heating system. "The beauty of the system" says Servite's Development Director Andrew Kilpatrick " is that we are able to sell deeply discounted electricity on to our tenants and yet still make some money on the generation side."
Keith Stocker, sales manager of Nedario UK says that the amount of CHP units in housing is still small but interest is growing. "Our main market is commercial. I would say that of 350 units we have installed in the UK, just five are in housing but we have a lot of enquiries coming in, especially from councils and housing associations who are in the process of refurbishing old district heating systems." To get the most from a CHP system Stocker reckons you need to design it carefully so that you are meeting just the baseload. "A gas fired CHP unit outputs around 30% electricity and 70% hot water and when correctly specified they can run at efficiencies of 70% or even 80%. But if you try to supply all the heating needs from a CHP system, you will find that you end up wasting an awful lot of fuel." The smallest CHP engine that Nedario produce is 90 kw which makes it impractical on units of less than 100 people. Ideally, you need a mixed use development so that shops or offices can spread out the overall load.
Quietly dropped
But what of private sector housing? The nearest they have come so far is a scheme devised by architect Terry Farrell & Partners in 1995 for the new settlement at Cambourne near Cambridge. This involved a CHP plant supplying hot water and electricity to the entire community of 3300 homes: the plant was to be fired by a mixture of straw burning and coppicing grown on local set aside land. The intention was to replace the gas infrastructure but the plans were quietly dropped when, after undertaking market research, the developers decided that potential buyers would be put off by not being able to cook with gas.
The Greenwich Millennium Village which will be largely unsubsidised private housing is committed to using CHP, though at present the details are unavailable. Similarly it is likely that the second Millennium scheme at Allerton Bywater near Leeds will also incorporate CHP. Yet these are flagship green housebuilding projects: we have yet to see CHP featuring in less high profile private developments.
Cultural roots
It has long been supposed that part of the reason for this is cultural: we British wish to privately own as much as we can and are therefore suspicious of schemes which serve to take our heat generation away from us. It may be okay in large social housing schemes but British housebuyers are always presumed to be even more conservative than British housebuilders. For CHP to prosper in the private sector, this myth needs to be exploded which is why the Lerwick experience is so important. A community CHP and district heating scheme supplying power to private households is little different to buying your gas or electricity from remote utility companies yet potentially it has several advantages including reduced fuel costs and reduced C02 emissions. By far the greatest installation cost is in running the infrastructure around the site which makes it ideal for greenfield and newbuild sites.
Source
Building Homes
