PhD Thesis - Energy Systems Research Unit - University of Strathclyde

ii.In the latter case the magnitude of the remaining terms in the cash flowequation are, dependent on the energy quantity they represent multiplied bythe assumed financial parameter (e.g. FIT), applicable for that specific term;both assumed constant for any given scenario.For the same financial parameters, changes in an energy quantity due to (for example)a reduction in fuel consumption as a result of improving the building fabric, will leadto a different financial result for each term making up the CF of each scenario. Forthe different scenarios proposed therefore, the individual terms making up the CF,the resulting CF and eventually the PW reflect the aggregated effect of varyingelectricity tariffs, the energy quantities and the economic parameters assumed.Considering (for example) the specific case of the current (Scenario 2 Low/Current efficiency )and high (Scenario 2 Low/High efficiency ) appliances’ electrical efficiency for the 6household building with low efficiency fabric, Figure 5.13 compares the CF and itsindividual components for the two scenarios.Recalling that for the same building fabric improving the electrical efficiency ofappliances does not affect the thermal performance of the micro-trigeneration system(fuel consumption in unaltered), but results in an increase in net electrical exportsand a decrease in net imports, it can be observed by comparing the plots obtained forScenario 2 Low/Current efficiency and Scenario 2 Low/High efficiency , that the individual termsmaking up the CF reflect these changes. Where an individual term is independent ofthe electricity tariff the change is constant throughout the electricity tariffs range.In this case the aggregated effect of the different terms on the CF and the PW plot isthat, as discussed, with improving household appliances’ electrical efficiency, thePW of the project is reduced with a significant reduction occurring with increasingelectricity tariffs.A similar reasoning can be applied to all other cases.212