Micro-CHP can deliver significant carbon savings if used in the right applications 

27 November 2007
Carbon Trust field trial shows greatest carbon savings for commercial applications and older, larger homes 

Findings from the most in-depth field trial to date on Micro-CHP (combined heat and power) were released today by the Carbon Trust, showing that Micro-CHP technology has significant potential to deliver CO2 savings in small commercial environments and certain types of homes.

For small businesses, the trial has demonstrated that Micro-CHP systems can cut overall site CO2 emissions by 15 to 20 per cent when installed as the lead boiler in appropriate applications, such as care homes, community housing schemes and leisure centres. These types of Micro-CHP installations can also reduce energy bills by thousands of pounds each year due to the reduced demand for grid electricity.

For domestic users, the results show that the current generation of Micro-CHP systems is best suited to larger homes with three or more bedrooms, or older houses where it is not currently cost effective to improve insulation, such as housing with solid brick walls. In such homes, Micro-CHP can potentially deliver carbon savings of between five and ten per cent – with typical reductions between 200kg and 800kg of CO2 each year. However, the currently available systems appear to offer limited benefits for smaller and newer houses.

Deploying devices in the most appropriate applications is the key to maximising benefits. The common success factor for both domestic and commercial applications is matching the thermal output of Micro-CHP devices to the buildings where they are used, to ensure that they operate for many hours at a time, rather than intermittently. The carbon saving potential of Micro-CHP has therefore been found to be best in buildings which require long and consistent heating periods.

Mark Williamson, Director of Innovations at the Carbon Trust, said:
“Our analysis of more than 30,000 days worth of data shows that Micro-CHP systems can deliver significant CO2 savings for small businesses and certain types of houses. However, if the market for this exciting technology is to develop, it needs a policy framework which provides appropriate incentives to target applications which offer worthwhile carbon savings.”

Phil Woolas, Minister for Climate Change and Environment, commented:
“Harnessing more low carbon energy is a must if we are to reduce our emissions and combat climate change successfully. I welcome the Carbon Trust's research because it underlines the emission savings and financial gains of installing Micro-CHP. This technology has the potential to make a major contribution in the deployment of microgeneration and play an integral role in moving to a low carbon energy mix.”

In light of the field trial findings, the Carbon Trust is proposing that Micro-CHP should be considered as eligible for Government policy support, alongside other micro-generation technologies. However, any such support must be linked to clear criteria which ensure that installation of Micro-CHP devices is only encouraged in applications where there is a high likelihood of carbon savings being achieved.

In order to achieve widespread uptake of Micro-CHP it will also be essential that customers have access to appropriate payments for locally generated electricity which is exported to the grid. This is particularly true in domestic environments, where the trial has shown that, on average, half of all electricity generated by a typical 1kWe Micro-CHP device is exported to the grid.

Feedback from customers involved in the trial has also highlighted some practical aspects of Micro-CHP performance which need to be enhanced. These include further improvements in device reliability and the need for an increase in installation and maintenance skills. However, these issues are typical for such an early stage of technology development and are expected to be resolved over the coming years as manufacturers continue to enhance their product and service offerings.

The trial has also showed that manufacturers should focus further on optimising the electrical performance of their Micro-CHP devices, as this is the key to achieving higher carbon savings in future. Analysis of the trial results suggests that an improvement in electrical efficiency of just three percentage points could lead to a near doubling of carbon savings for a typical house.

Dave Sowden, Chief Executive of the Micropower Council, said:
“This thorough piece of research based on real installations clearly demonstrates the potential of Micro-CHP as a key technology in helping to tackle carbon emissions from the large number of existing homes already connected to the natural gas network. This provides further evidence for the introduction of further policy measures to help deploy this promising technology as quickly as possible.”

Graham Meeks, Director of the Combined Heat & Power Association, said:
“These intermediate results from the trial are tremendously encouraging. They point to a future in which Micro-CHP can make a major contribution in our efforts to tackle carbon emissions from our homes and businesses. The Carbon Trust trials are an important step forward and continue to provide a thorough, independent and objective assessment of the performance of a number of Micro-CHP plants. This means that customers can invest in these units with the confidence that they are making a genuine impact in the fight against climate change.”


View the full report

 
 

Footnotes

Notes to editors
Sites involved in the trial – available for interview
Stanhope Street housing scheme, Newcastle
Built in 1974, the Stanhope Street housing scheme is an estate of 351 rented flats and maisonettes located in Newcastle. Rising fuel prices and a desire to reduce carbon emissions led the estate's owner, Places for People, to install a CHP unit providing district heating at a more affordable price to residents. Electricity produced by the CHP unit is directed back into the heating system to power pumps and boilers. The site has a heat demand of 71,357 kWh a year. The CHP unit has made a saving of 18% in CO2 emissions, equivalent to 8.1 tonnes of CO2 a year.

Derek Watters, Sustainable Development Manager at Places for People said:
"With fuel costs rising, we wanted to provide our customers at Stanhope Street with more affordable warmth. We are also committed to reducing the estate's carbon footprint. The Micro-CHP unit has been an ideal solution providing both cheaper heating for Stanhope residents and a significant reduction in carbon emissions."

Royal Court nursing home, Cheltenham
Royal Court is a residential home located in Cheltenham which provides accommodation and care for between 45 and 50 vulnerable customers. The customers’ vulnerability makes them particularly dependent on the constant heating of the rooms and communal areas. Bromford Housing Group has been impressed with the reliability and efficiency of the CHP unit. The home has an annual heat demand of 79,231 kWh. The CHP unit has provided carbon savings of 17%, equivalent to 8.5 tonnes of CO2 a year.

Roger Howells, Head of Specialist Services at Bromford said: "As an organisation we are constantly looking for innovative solutions to improve our efficiency and reduce our carbon emissions. Bromford was one of the first to install a Micro-CHP unit in a residential scheme and at Royal Court we are very pleased to confirm that the investment has really paid off. We are working towards identifying more of our schemes that could benefit from the installation of this type of heat and power system."

East End Farmhouse, near Cheltenham
East End Farmhouse was built around 100 years ago in Charlton Kings, near Cheltenham. The property has 4 bedrooms and an annual heat demand of 25,410 kWh. The owners, Peter and Elaine Boait, decided to install a micro CHP unit just over three years ago which has provided carbon savings of 10%, equivalent to 0.6 tonnes of CO2 a year. They export excess electricity, not used in his house, back to the grid and receive payment for it.

Peter Boait, owner of East End Farmhouse, explains:
“I wanted to install a micro CHP unit because I think we all have a moral obligation to reduce our carbon footprint. Micro CHP is a very effective way of reducing the emissions and energy costs of an older house - ours replaced an old gas boiler so both our gas and electricity bills have been substantially reduced. It is also rather nice to be selling a useful product in the form of export electricity and get a quarterly cheque for it. So we hope and expect ours will have a long life in our house.”

About Micro-CHP:

  • Micro-CHP (combined heat and power) systems generate both heat and electricity locally and reduce costs and carbon emissions by offsetting the need for centrally-generated electricity from the grid
  • Various Micro-CHP products are commercially available and others are nearing market but to date there has been limited data available regarding the real-world performance of Micro-CHP systems.
  • For small commercial applications most Micro-CHP devices are based on internal combustion (IC) engine technology, originally adapted from the automotive sector. For domestic applications, most currently available and near market Micro-CHP units in Europe are based on Stirling engine technology. A number of fuel cell-based Micro-CHP systems are also under development but they are still a few years away from market-ready products.

The Carbon Trust Micro-CHP Accelerator:

  • The Micro-CHP Accelerator involves one of the largest and most comprehensive assessments of Micro-CHP ever undertaken. It includes a wide range of activities to better understand the potential benefits of different Micro-CHP technologies and the barriers to their adoption.
  • The project aims to identify applications where Micro-CHP has the greatest chance of offering carbon savings and to investigate the factors which have the most significant impact on performance. It also aims to inform future policy decisions and assist device manufacturers in their product development.
  • The project includes a field trial of 87 Micro-CHP units in a range of domestic and small commercial environments and covers 10 different models from 7 different manufacturers. It also includes a corresponding field trial of condensing boilers to provide a relevant baseline against which to compare Micro-CHP performance.
  • The project uses a rigorous methodology to ensure high quality data is captured and to allow robust, independent assessments to be made. At each site, 20 data parameters are measured at 5-minute intervals throughout each day and around 33,000 days of system operation have been analysed so far.
  • The project is ongoing and this report is an interim update which presents a range of indicative findings based on the considerable volume of data collected to date. Further work is in progress and a final report is due to be published in 2008.

The Carbon Trust

  • The Carbon Trust is a private company set up by government in response to the threat of climate change, to accelerate the move to a low carbon economy by developing commercial low carbon technologies and helping organisations reduce their carbon emissions. The Carbon Trust works with UK business and the public sector through its work in five complementary areas: insights, solutions, innovations, enterprises and investments. Together these help to explain, deliver, develop, create and finance low carbon enterprise.
  • The Carbon Trust is funded by the Department for Environment, Food and Rural Affairs (Defra), the Department for Business, Enterprise and Regulatory Reform (BERR), the Scottish Government, the Welsh Assembly Government and Invest Northern Ireland.

 
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