The total energy approach: Evolution of combined heat and power for district heating and/or cooling

Combined heat and power (CHP) generation is not a new concept, but it provides an elegant solution to some of our present fuel problems, offering, as it does, 80% or greater efficiency. However, Great Britain lags behind other European countries with respect to the rate of introduction of CHP together with district heating and/or cooling (DHC) systems. Reviews of (i) the historical development of the designs of DHC pipelines, from insulated pipes in air-filled ducts to the modern preinsulated pipes buried in the ground, and (ii) sources of energy as well as developments in metering and control, for CHP-DHC systems, are presented. The cost effectiveness of each CHP-DHC system is highly sensitive to unit fuel prices, current discount rate, as well as the capital cost incurred. In the best interests of Britain, major governmental investments are now needed urgently in order to encourage the wider adoption of these systems.