An evaluation of distributed cogeneration for disaggregated consumer populations on Islands : the case of Guernsey

Abstract

There is currently no strategic energy conservation management on the island of Guernsey, nor may it be adequate to leave energy management entirely to market forces. Market mechanisms of themselves may not be adequate to balance the intrinsically conflicting objectives of obtaining the cheapest possible energy, ensure security of supply, reduce the risks associated with over-dependence on particular energy sources (such as petroleum products), whilst protecting the environment. Properly formed data sets, together with time-based capital budgeting, are necessary prerequisites for balanced political choice. The thesis deals with the central issues of strategy by use of a soft systems methodology. It develops the proposition that energy needs for communities, or 'clusters' of demand, might be better met and matched by taking local needs for energy and matching them to locally, parish based, generated supplies. This approach runs counter to much current public energy policy in relation to utilities and supply-demand relationships. Quality, Quantity and Timing (QQT) computer based models are developed for each parish on Guernsey which reflect diurnal/seasonal patterns of demand and explain how variability of demand on various time scales may influence supply technology choices. Parish energy sources are compared on a least-cost basis and a simulation model is used to take into account the variability in the supply potential of alternative renewable sources of energy, and it® relationship to variability of demand (as exposed by QQT modelling). The work described uses computer models based upon SuperCalc 5 advanced spreadsheet modelling techniques, dBASE III Plus database/programming language and compiled under Clipper. A TurboPascal simulation programme was also considered but ultimately rejected in the present context. As well as dealing with the central issues of strategy, and the tactics for achieving them, the thesis analyses the prospect that decentralisation of the power and energy base (through distributed cogeneration) could be a much better strategy to follow for an island such as Guernsey. One outcome of the soft system and simulation modelling approaches was a proposed formal 'States of Guernsey Energy Management System' to provide a mobilising strategy and an environment for market forces to operate within. This focuses on the energy service requirements of each parish and attempts to answer such questions as; "do we expand the present centralised Island supply of fuels and electricity, or do we instead use less fossil fuels to meet the energy services we want by other means, at lower cost ?". The fundamental proposition of the thesis is that much improved means exist for the efficient utilisation of important resources (energy, capital, manpower) within Guernsey and importantly, a wide range of other well populated ‘energy clusters’.