General Renewables

For more information try:

West Wales ECO Centre for fact sheets   http://www.ecocentre.org.uk/

Intermediate Technology Development Group.  Follow Technical Information Service for factfiles www.itdg.org

Low Carbon Building Programme  for grants, approved installers and information http://www.est.org.uk/myhome/generating/grants/ or telephone 0800 915 7722

Also for Wales Real Cymru  www.realcymru.org.uk

Renewable energy in the Thames Valley www.tvenergy.org

All equipment and installers should be checked for approval on the DTI website. This is not only a requirement for grant approval but also the only independent test of suitability for the intended use. http://www.lowcarbonbuildings.org.uk/home/

Use of Excess Energy

The 1 to 1.5 kW from a small generator may be sufficient for the average household power requirements, but for much of the time loads will be much lower than this, while for shorter periods they will be greater. At these times it will be necessary to supplement supply from a battery reserve or the mains.

Excess energy can be dissipated in several ways. Metering the exchange of electricity through the grid is currently expensive and suited to large scale producers. It may be added to the mains unmetered, stored in large (expensive) batteries or used to heat up water (which represents nearly 24% of domestic energy use and 4% of CO₂ production overall.)
For more information try:

Tyndall Centre report March 2005 on distributing energy from micro power generators.   www.tyndall.ac.uk/research/theme2/final_reports/it1_33.pdf

Wind Power

The costs are dependant on the size of the installation, costing around £18,000 for 6kW down to £90,000 for 600 kW. Smaller roof mounted installations of 1 to 1.5 kW have become available from around £1000 which can be connected directly to the household mains. For approved designs, grants of £1000 per kW (maximum £5000) are available

Newer designs produce less noise but still need windspeeds of 6m/s to 10m/s to be viable. The best sites are on exposed high or rising ground, mounted as high above the ground as possible.

For more information try:

Danish Wind Association    www.windpower.org

The British Wind Energy Association   www.bwea.com

Photo Voltaic  'Solar Panels'  / PV

Though they are becoming cheaper these are expensive as a direct replacement for grid electricity, though they may be suitable for structures with no mains connection or where it would be expensive, such as street signs, bus shelters, remote lighting. A 2 kW system could cost between £12,000 and £14,000 and occupy from 12m² to 40m² depending on the technology used and the location.

More efficient types are also more expensive, cancelling out price advantages. Some newer technologies have potential but are unproven. Panels need to be sited facing south in a situation where the sunlight is unobstructed. Grants of 50% are currently available.

For more information try:

British Photovoltaic Association    www.pv-uk.org.uk

Micro-Hydro

This refers to small schemes (under 100kW). The amount of energy available depends on the height and flow rate of the water (bearing in mind that less than half the water can usually be extracted for environmental reasons, water abstraction licences are required.) Ideally there should be a short, steep direct course from the source to the turbine. Higher speed flow rather than large volume is preferred but not necessary.

Cost from £8,000 to £10,000 for 5 kW falling to around £1,000 per kW for larger schemes. The grants available are £1,000 per kW (to a maximum of £5,000). Potential sites need to be carefully surveyed before going ahead. Payback times from 3 to 20 years depending on conditions.

For more information try:

Mini Hydro Guide, British Hydropower Association   www.british-hydro.org

Evans Engineering   www.microhydro.com

 

Solar Water Heating

Although outputs vary depending on the season, for most of the year considerable amounts of water can be heated, providing up to 70% of annual needs and savings of £100 to £200 fro a single panel. Installed panels cost around £3,000, less if self installed and cheaper still if DIY built. Grants of £400 are available.

Size required depends on the design, circulating fluid collectors are less efficient but cheaper than evacuated tube collectors. Different systems are employed to deal with freezing up in winter. Newer systems can be used to produce cooled air on summer nights.

For more information try:

Solar Trade Association www.greenenergy.org.uk/sta

Solar Energy Technologies Program (US Dept of Energy) www.eere.energy.gov/solar

Build Your Own Solar ??  www.bigginhill.co.uk/solar.htm

 

Ground Source Heat Pumps

Heat pumps work in the same way as a fridge, using compression and expansion of a gas to collect heat from a low temperature source and deliver it at a higher temperature. The heat energy produced is about 4 times as much as the electricity used to recover it. They can use air as a source but drawing heat from the ground is more efficient due to the smaller temperature variation. To maximise efficiency the output temperature is limited to 40^oC to 50^oC, suitable for space heating, especially under floor heating.

Heat collectors are coiled plastic pipes buried in 1.5m deep trenches or copper pipes in vertical bore holes. These are expected to last for at least 40 years. Costs of between £5,000 and £10,000 for a 5kW output (sufficient for a well insulated house) depend on the details of the situation. Grants of £1,200 are available and maintenance costs are low.

For more information try:

GSHP Club, National Energy Foundation     www.nef.org.uk/gshp

UK Heatpump Network www.heatpumpnet.org.uk

Kensaheatpumps, follow faq?s for fact files  www.kensaengineering.com/index.html

EarthEnergy Limited, leading installers, part of the GeoScience Group  www.earthenergy.co.uk

 

Biomass

Biomass uses organic materials as a source of energy. Although the usual combustion gases are produced they are used to regrow the crops used. There is no net carbon dioxide produced since the same amount is re-absorbed. Wood and charcoal are both forms of biomass but there are some additional alternatives.

For more information try:

General biomass information  www.defra.gov.uk/farm/acu/energy/energy.htm

 

Wood Pellets

Wood pellets, uniform, compressed and dried pieces (and to a lesser extent wood chips) are a fuel that can be automatically fed into a boiler, via a screw, giving the advantage of greater automation and control. Use depends on local availability of fuel. As many woodlands are currently unmanaged there is the potential to produce regular, sustainable supplies by techniques such as coppicing.

For more information try:

Logpile, National Energy Foundation  www.nef.org.uk/logpile/index.htm

Welsh Biofuels   www.welsh-biofuels.co.uk

 

Anaerobic Digestors (AD) /Biogas

In the absence of air organic matter breaks down, with the assistance of bacteria, into methane and carbon dioxide. This happens in the stomachs of cows and in landfill sites, where the gas must be drawn off to alleviate safety hazards and may be used to generate electricity.

Any organic matter can be used but the supply needs to be regular (and fairly large) to make the process viable. Quite a large commitment in terms of buildings and equipment is required. The gas produced can be burnt to provide heat, to generate electricity (or both).

For more information try:

BiogasWorks (US)  www.biogasworks.com

Trade Association of UK Bioenergy Indust www.britishbiogen.co.uk/links/links.htm

 

Transport

Diesel engines are capable of running on practically any combustible material, and vegetable oils contain sufficient energy to replace hydrocarbon fuels. Many diesel engines can use them in a raw (filtered) state but others need a thinner fluid, produced by adding small amounts of mineral diesel and called biodiesel. Biodiesel is becoming more readily available, meets the requirements of manufacturers warranties and can be used without engine modification.

As a raw material vegetable oil is more expensive than the hydrocarbon equivalent, though there is plenty of land set aside in the EU that could be used for crops, but attracts lower taxes making it lower priced at the pumps. Tax must be paid for any vegetable oil used in vehicles, such as used chip shop cooking oil.

For more information try:

British Association for Bio Fuels and Oils  www.biodiesel.co.uk

Links to related topics www.biofuels.fsnet.co.uk

Goat Industries for conversion kits, compatibility etc www.vegetableoildiesel.co.uk

Find nearest suppliers  www.biodieselfillingstations.co.uk