A Practical Guide to Creating a Sustainable Community Building

Subject guidesGuide 7: Renewable energy options appropriate for community buildingsApplication and practical considerations Overall a biomass system is considered ‘CO 2netural’ with net ZeroCarbon emissions (carbon used in growing = carbon released inburning). However, this relies on the fuel supply being managedsustainably. Use of the technology can support new jobs and enterprises in anarea in forestry and chip processing or short rotation coppicing. Planning issues include: storage space for fuel; fire safety regs; fluevent specifically designed for wood fuel appliance; smokeless zone.Local examples wherethe technology is in useAveron Leisure Centre,Invergordon, Easter RossGeothermal - using the temperature of the earth.Earth temperature a few metres below ground level stays constantat 11-12C throughout the year. This geothermal heat can be pumpedinto a building using a Ground Source Heat Pump (GSHP). Can meet 100% of space heating requirements; usually only able topre-heat domestic hot water – with a top- up heating sourcerequired. Installation costs are cheaper if done during new build, as installationcan be combined with other site earthworks. GSHP can be cheaper to run space heating than oil, LPG and electricstorage heaters, but is more expensive than mains gas. Planning considerations: is under floor heating possible? (radiatorscan also be used); is there space and suitable ground material for thetrench which will bury the ground loop?; what auxiliary heating willyou use? Environmental disadvantages are:– the use of mains electric isrequired to operate the pump (every unit used in pump produces 3-4units ground heat) however this still produces less carbon emissionsthan a conventional boiler; also, refrigerants are used in the system.Glenelg Community Hall,Skye & Lochalsh, hasinstalled a GSHP in the newbuilding to provideunderfloor heating for allrooms in the hallNew community centre atGlendale, Isle of Skye, Skye& LochalshGreen Electricity TariffsBuying Green Tariff electricity from the mains means your electricitysupplier is obliged to source an amount equal to the power youconsume from existing renewable energy sources, through the mainsgrid. Electricity is supplied to your building in exactly the same way – butis purchased by your supplier from a green electricity source such ashydro or wind farm. You pay a premium for a Green Tariff, as generation from renewablesis more costly, so your power is more expensive per unit to purchase(a few pounds per month – cost varies with supplier). The benefit to the community is not highly visible, but thiscommunicates to energy companies that there is a consumerpreference for renewables. When you buy ‘regular’ electricity, a small part will be fromrenewables, set by government targets and legislation which requireenergy suppliers to source a minimum percentage of the electricitythey sell from defined renewables sources.Glenelg Community Hall,Skye & Lochalsh, ispurchasing Green tariffelectricity to power thepump which drives theGSHP system43