Small‐Scale Combined Heat and Power Systems: The prospects for a distributed micro‐generator in the ‘net‐zero’ transition within the UK

Geoffrey Hammond, Adam A. Titley

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Small-scale combined heat and power (micro-CHP or mCHP) plants generate heat in the process of localised electricity production that can usefully be captured and employed for domestic space and water heating. Studies of the relative merits of three alternative network-connected mCHP plants are reviewed based respectively on an Internal Combustion engine (ICE), a Stirling engine (SE), and a Fuel Cell (FC). Each plant will, in most cases, result in lower carbon dioxide (CO2) emissions, relative to those from the most efficient condensing boilers. In addition, they lead to operational cost savings for the consumer, depending on house type. However, their capital costs are presently more expensive than a conventional boiler, with the FC being prohibitively so. The ICE and SE variants display the greatest economic and environmental benefit. Nevertheless, the performance and costs associated with these innovative technologies have rapidly improved over the last decade or so. Comparisons are also made with heat pumps that are seen as a major low-carbon competitor by the United Kingdom (UK) Government. Finally, the potential role of micro-CHP as part of a cluster of different micro-generators attached to contrasting dwellings is considered. The review places mCHP systems in the context of the UK transition pathway to net-zero CO2 emissions by 2050, whilst meeting residential energy demand. However, the lessons learned are applicable to many industrialised countries.
Original languageEnglish
Article number6049
Number of pages32
Issue number16
Publication statusPublished - 20 Aug 2022

Bibliographical note

Funding Information:
Adam Titley wishes to thank the Bolton Council, as well as the Higher Education Funding Council for England, for financial support of his studies. Both authors are grateful to Steve Petersen of the Stirling Technology, Inc. for his advice in respect to the performance of Stirling engine-based micro-CHP plants. However, the views expressed are those of the authors alone, and do not necessarily reflect the opinions of the collaborators or the policies of the funding bodies. Finally, the authors are grateful to the late Mrs Gill Green (Department of Mechanical Engineering, University of Bath) for her care in preparing the figures. The authors’ names are listed alphabetically.

Funding Information:
This research was funded by UK research grants awarded by the UKRI Energy Programme, originally as part of the SUPERGEN ‘Highly Distributed Power Systems ’ (HDPS) Consortium [under Grant GR/T28836/01; for which Prof. Geoffrey Hammond was a Co-Investigator]; it was renewed as the ‘Highly Distributed Energy Futures ’ (HiDEF) Consortium [under Grant EP/G031681/1; for which Prof. Hammond was again a Co-Investigator]. These consortia, which were led by Prof. Graeme Burt and Prof. David Infield of Strathclyde University (Glasgow, Scotland), involved a number of academic and industrial partners. Prof. Hammond also jointly led a large consortium of university partners (jointly with Prof. Peter Pearson—an energy economist, who holds of honorary posts at Cardiff University and Imperial College London) with strategic funding from e.on UK (the electricity generator) and the UKRI Energy Programme to evaluate the role of electricity within the context of ‘Transition Pathways to a Low Carbon Economy ’ [under Grant EP/F022832/1], and its successor project solely funded by the UKRI entitled ‘Realising Transition Pathways: Whole Systems Analysis for a UK More Electric Low Carbon Energy Future ’ [under Grant EP/K005316/1].


  • Stirling engine
  • carbon dioxide emissions
  • combined heat and power (CHP)
  • energy efficiency
  • fuel cell
  • internal combustion engine
  • micro-CHP
  • micro-generation
  • residential sector

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Building and Construction
  • Fuel Technology
  • Engineering (miscellaneous)
  • Energy Engineering and Power Technology
  • Energy (miscellaneous)
  • Control and Optimization
  • Electrical and Electronic Engineering


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