Renewable energy: sustainable solutions

What factors should be considered prior to installing renewable energy systems?

• Check that all viable energy conservation measures have been installed. (See Energy Use Chapter)
• Examine what renewable resources are available and whether they can be used for electricity and/or heat generation; then estimate the need in terms of output and check the table below for options.
• Take professional advice over placement and sizing of the chosen technology and have early discussions with the local planning authority, especially if there is a likely visual or traffic impact.
• Be aware that small-scale renewable energy systems can be the lowest cost option in remote locations where there is not an existing grid connection.
• Assess the potential for using more than one type of renewable energy resource or a hybrid supply system (e.g. small wind/diesel engine generating unit), or of gaining a direct supply from an established local renewables or a combined heat and power (CHP) plant.

What other action can indirectly support renewable energy use?

• Purchase 'green' tariff electricity, from an appropriate supplier. Best deals can be worked out from specialist websites / checklists.
• Plant trees to compensate for carbon dioxide emissions likely to be generated by the development (known as ‘carbon offset’). Forestry can be managed so that local woodheat schemes can flourish.
• Ensure building design utilises solar ‘gain’ effectively, employing passive solar heat traps such as conservatories and atria.

What are the main options for renewable energy generation?

(No ranking is implied. Site location will normally dictate the choice of technology.)

• Solar hot water systems use collectors, such as solar panels, to capture heat from the sun. Fluid is circulated via a pump (usually water) to a heat transfer store for later use. This is most commonly used to provide domestic hot water.
• Bio-fuels (derived from energy crops, agricultural and forestry residues) can be used in simple combustion processes to supply heat. They can also fuel more complex CHP schemes to generate electricity and distribute heat.
• Modern wood fired boilers (domestic & large-scale) are automated, very efficient, and some are eligible for grant funding.
• Photovoltaics cells (PVs) use solar power to generate electricity and can be free-standing in arrays, or incorporated into roofing materials, glazing or wall cladding
• Wind turbines – small wind generators, both on-grid and off-grid, are usually more cost effective than photovoltaics where there is a reasonable wind resource. They can be incorporated into larger buildings or sited in their grounds. Check wind speed maps and avoid major obstructions within 60 metres.
• Ground source heat pumps can provide a viable alternative form of heating and cooling, especially if the electricity required to run them is obtained from renewable sources.
• Hydro - there is potential for small-scale hydro schemes where there is a reasonable flow and ‘head’ of river water. If successful it can be considerably more cost-effective than wind generation or photovoltaics.