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Alternative & Renewable Energy Generators

CHP, Condensing Boilers, Fuel Cells and Geothermal Energy (Page 2a).

CHP and Condensing Boilers both perform the function of extracting more energy from heat exchangers (normally powered by fossil fuels) hence their advantage is simply an increase in efficiency. They are not radical and by continuing to use fossil fuels they will contribute to global warming. However, the vision is that the technologies will be widely adopted. If that were to happen the saving in energy would be considerable and help the UK meet its Kyoto targets.
Fuel Cells are still in the R & D stage but hold great promise, including use for road transport. The basic fuel can either be fossil or renewable so they are not unquestionably a panacea. Geothermal energy is a renewable source and surprisingly can be used in cool climates such as the UK, although geothermal technologies are more practical and economic in hot climates.

Cretan Wild Flower Ducks on a Beach
Cretan Wild Flower Ducks on a Beach
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Alternative Energy Sources Index
Down Are you wondering what you can do and would like some help and information?
Down to Overview of energy sources An Overview Down Biomass and Biofuels Down CHP (Cogeneration)
Down Condensing Boilers Down Fuel Cells Down Geothermal and Air-source
Down Incineration Down Liquefied Petroleum Gas Down Nuclear Power
Down Solar Energy Down Water Power Down Wind Power

If your interest is green energy suppliers (eg domestic electricity), see Page 3, 'Energy Conservation'.

If your interest is motor vehicles see the dedicated section under Energy & Ecology.
You may also find some relevant information below under Fuel Cells.

Click to read our main Reference page on Renewable Energy and other 'Clean' Energy sources.

Combined Heat and Power (CHP)
  Combined Heat and Power (CHP) is a cheap, efficient, but none radical, way to generate heat and power simultaneously. In the US and Europe other names are "Cogeneration" and "Total Energy". In essence CHP generates heat together with an amount of electricity which can be used locally without transmission losses. The cogeneration technique leads to an increase in efficiency thus reducing costs and carbon emissions per unit of generated power. Practical implementations can, in principle, use a wide variety of fuels. At a domestic level, you might expect to have Micro-CHP in your home soon but the news is not very good. Wild claims abound but the only convincing one seems to be by Disenco. On a slightly larger scale mini-CHP systems, suited to small organisations or community centres etc, have an established record. A wide variety of links are shown below but you can read our popular summary (Reference page) of CHP, Micro-CHP, Mini-CHP here.
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    Ceres Power, the AIM-quoted fuel cell group, has a £2.7 million contract with Centrica (trading as British Gas), part-funded by the DTI, to develop Combined Heat and Power (CHP) units for the UK residential market. The programme will design, build and evaluate fuel cell CHP units, delivering electricity, heating and hot water, to reduce costs and CO2 emissions.
    Cogen Europe is the European Trade Association for the Promotion of cogeneration. Arguing that cogeneration is the most efficient way to deliver heating, cooling and electricity, its principal goal is to work towards the wider use of cogeneration in Europe for a sustainable energy future. They produce publications about CHP.
    The Combined Heat and Power Association (CHPA) site is designed to promote CHP and district heating in the UK.

The CHP Club is an initiative under the Carbon Trust's Delivery programme, aimed at assisting users and potential users in getting maximum benefits from CHP. All the advice and services available, including forums and advice facilities on CHP related topics, are impartial, professional and free.

    CHP Focus is a DECC initiative to support the development of combined heat and power in the UK. This useful resource covers alternative fuels (waste and renewable) the environmental benefits of CHP, micro CHP and they are adding information on a continuous basis.
    CHPQA, the CHP Quality Assurance programme, carried out on behalf of DECC in consultation with Scottish, Welsh and Northern Ireland Depts, provides the means to assess and monitor good quality CHP Capacity.
    EC Power formed in 1994 by Danish civil engineers produces mini-CHP units powered by diesel or natural gas. In Denmark, large scale CHP systems have been operating for over 50 years, today covering about 60% of households.
The US EPA's CHP Partnership is a voluntary program seeking to reduce the environmental impact of power generation by promoting use of CHP. It works with energy users, CHP industry, govts etc to support new projects and promote their energy, environmental, and economic benefits. Their Catalogue of CHP Technologies gives overviews of how CHP systems work.
Special interest for the UK
  Microgen Energy Limited is a specialist in micro combined heat and power based on unique Free-Piston Stirling generator technology. This is the first site we have found in Q1 2007 which gives clear explanations and a promise for domestic CHP units for the UK (although not until 2008). An interesting site with lots of relevant information, worth visiting.
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Combined Heat and Power (CHP)
continued ....
  TIPS (Transformation and Innovation in Power Systems): the German electricity system is undergoing a transformation. Driven by factors including market liberalisation, the necessity for power plant replacement, environmental regulation and new technologies, the TIPS project aims to guide this transformation in a more sustainable direction.
    Vital Energi specialises in providing innovative Combined Heat and Power and Community Energy solutions to public and private sector customers.
Stirling Engine
Schematic of model Stirling engine by
  The Stirling Engine is alive and well, even though you won't see many around. It can be used to provide CHP and is used for other specialist applications. If you are technically minded and don't yet know how it works, try the following links, they will give you hours of fun, or click here for our summary Reference page on Stirling Motors and Generators.
Click on the diagram (used by permission of
  How Stuff Works: there are hundreds of ways to put together a Stirling engine. Here you'll learn about the Stirling cycle and see how two different configurations of this engine work. We think: one of the best explanations.
    Koichi Hirata says if you have some machine tools and know how to use them, you can easily build model Stirling engines. There are links to other pages with plans for easily constructed Stirling engines with assembly instructions. We think: not so easy but there is one 'Blue Peter' example. explains how Stirling engines work and answers many peripheral questions for the inquisitive. It also offers demonstration models for purchase. We think: an absorbing and informative set of FAQs.
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Condensing Boilers   Condensing Boilers fit into the scheme of energy saving in a similar way to Micro CHP boilers. Both achieve a high efficiency by using heat that would otherwise be wasted. The technical difference is that condensing boilers simply increase the heat transferred to the water while CHP boilers provide electricity via an engine. In practice there is a more commanding difference because condensing boilers are currently available with a track record, whereas in 2006, Micro CHP boilers have yet to penetrate the market.
Condensing boilers are more complex than their predecessors which makes them more expensive and less reliable over their lifetime.
In England and Wales the regulations require that all new gas boilers should be 'A' or 'B' efficiency rated and, in effect, that means condensing types. Certain exceptions are allowed but customers who take advantage of these should be aware of a nasty sting in the tail.
Below are some related links but for a useful summary click here for our Reference page on Condensing Boilers.
    The Boiler Efficiency Database gives efficiency information on gas, LPG and oil boilers together with advice on how to choose a suitable boiler.
Sample of the official Gas Safe logo
Sample logo.
  Gas Safety Register: following a review by the Health and Safety Executive a new gas registration scheme was set up to provide a clearer focus on gas safety and a simpler registration procedure. All gas engineers in Great Britain and the Isle of Man must, by law, be Gas Safe registered. This replace the CORGI registration scheme in April 2009. Check that any gas engineers you employ are qualified to use one of the the official logos.
    Energy Saving Trust gives advice and information on climate change how the house and car owner can save energy.
    Heating and Hot Water Industry Council gives information on manufacturers, installers, regulations and calculators; a very accessible and useful site.
The National Energy Foundation gives information on condensing boilers, what size you need, how to get them installed and how to save energy. The site includes a CO2 calculator.
The Oil Firing Technical Association (OFTEC) specialises in oil heating and cooking for consumers, technicians and specifiers.
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Fuel Cells

Fuel Cell Bus: Click to enlarge
German Fuel-Cell bus. Courtesy: Neoplan.

  Fuel Cells were invented way back in the 19th century but have not become popular in the mass market, partly because they are very expensive and the alternatives were more appropriate for their time. In addition they can be large, difficult to operate and the technology is complex . More research and development is needed but nevertheless they are currently being used in a small way. Now that the need for clean energy, with low or zero emission, is urgently recognised it is to be expected that fuel cells will become practical alternatives soon. Below are some informative links but click here for our summary Reference page on Fuel Cells.
If your interest is electric batteries, see the topic on the Hazardous Waste page, or click here for a description of battery types on the Reference page Electric Batteries and Cells.
  Ceres Power, established in 2001 to acquire fuel cell intellectual property rights developed over the preceding ten years by Imperial College, award winning Ceres has developed and aims to exploit its fuel cell technology. Such exploitation involves producing core fuel cell components in-house and working with partners to integrate such components into finished products for end-users in the global distributed power generation market.
  Dais Analytic is a US firm who are developing new membrane fuel cell technologies for use in vehicles, homes and businesses. Their site includes a primer which will serve as an introduction to the topic.
  Fuel Cell Europe, the Internet home and communication centre for the fuel cell industry in Europe, promotes the most rapid commercialisation of this benign technology worldwide.
  E-sources is a project devised to make the Internet useful for the energy and environment community, in academia, commerce and public organisations. It offers news services, editorial opinion and information on topics including sections on fuel cells and biomass.
  Fuel Cells 2000 (US) give a brief description of what a fuel cell is and provide an interesting set of FAQs.
  MIRA have an automotive fuel-cell research and powertrain modeling unit as part of their Research and Technology Planning Group. This link gives a useful summary of some of the work particularly with respect to fuel cells.
  RWEnpower, (Regenesys Technologies Ltd) built a 12MWe electrical storage facility at Little Barford which uses Polysulfide bromide flow batteries. Although the facility was completed, due to engineering issues in scaling up the technology, it was never fully commissioned. The fuel cell plant is still owned by RWE.
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Geothermal and Air-source Energy

Geothermal energy is derived from beneath the earth's surface and is effectively an unlimited source of renewable energy. There are several different types of energy source and mechanisms for transferring it. An alternative air-source system which is less invasive, in installation terms, but of lower energy levels is based on exchanging heat with the ambient air. Well designed plants can be be cost effective and reliable as well as being clean in terms of emissions and visual impact. Suitably designed systems can operate in reverse, ie they can be used for cooling. More research, development and capital investment is required to make a major success of these resources. For more detail see our Reference page on Geothermal Energy and see links below.

  The Energy Efficiency and Renewable Energy Network (EREN), US Department of Energy provides a well informed site with answers to lots of questions although it is naturally US oriented.
    EarthEnergy is a specialist geothermal energy consultancy, designer and installer of ground source heat pump systems; these exploit renewable energy stored in the ground to provide one of the most energy efficient ways of heating and cooling buildings, with low CO2 emissions.
    The International Geothermal Association (IGA), aims to encourage research, development and utilization of geothermal resources worldwide through the publication of scientific and technical information. 
  HeatKing air source heat pump units are designed for domestic or light
commercial applications with a single outdoor unit giving a maximum power rating from 6-13kw. With a fan driven heat exchanger the systems have a Coefficient of Performance (COP = energy out/energy in) of about 2 to 4 and can function down to -15°C. Powered by electricity, they can replace small gas or oil systems with a claimed reduction in CO2 emissions of about 50%. The outdoor units must be sited carefully with regard for airflow, noise and associated condensate/ice production. With radiator CH the number of TRVs is limited; installation and maintenance requires accredited engineers.
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Page Originated: 21 July, 2001  Last amended: 3 May, 2013