تجزیه و تحلیل هزینه ها و فواید از بهره وری انرژی داخلی

There are a number of driving forces behind energy efficiency. In recent times, the Kyoto Protocol has been the most prominent in bringing energy efficiency to the fore. In some countries, the domestic sector has been highlighted as an area which has a significant potential for improvement. However, prior to the implementation of large-scale energy-efficiency programmes, it is important to evaluate whether they make economic sense. Heretofore, most economic evaluations of energy-efficiency programmes have concentrated purely on the associated costs of the programmes and the energy savings that result. At best, reductions in environmental benefits are also estimated, but rarely are other benefits calculated, such as increases in the levels of household comfort and improvements in human health. This paper endeavours to provide a template for ex ante economic evaluations of domestic energy-efficiency programmes. A comprehensive cost–benefit analysis of a programme to retrofit various energy-efficiency technologies and heating upgrades to the Irish dwelling stock is taken as a case study. The study demonstrates how energy savings, environmental benefits, and health and comfort improvements may be assessed. In so doing, it provides insights into the methodological difficulties and solutions for assessing the social efficiency of large-scale domestic energy-conservation projects.

Behind energy efficiency, there lies an array of so-called ‘driving forces’. In recent times, the Kyoto Protocol has been the most prominent in bringing energy efficiency to the fore. The Gothenburg Protocol on the reduction of acidification precursors also provides an incentive for European countries to improve energy efficiency and thereby reduce environmental emissions. In some countries, the domestic/residential sector has been highlighted as an area with considerable potential for improved energy efficiency. Improving energy efficiency in the domestic sector also has the potential to contribute to the resolution of a number of other social ills, principal of which are high rates of winter mortality which result from poor thermal standards of housing and the existence of fuel poverty, i.e. the inability to heat the home to an adequate (safe and comfortable) temperature, owing to low household income and poor household energy efficiency. However, prior to the implementation of energy-conservation measures in the domestic sector, it is important to assess whether such interventions are socially efficient. There are a number of studies which have endeavoured to evaluate monetarily the benefits of domestic energy conservation. The seminal work of Pezzey (1984), along with other notable studies by Henderson and Shorrock (1989) and van Harmelen and Uyterlinde (1999), show the clear net benefits of individual retrofitting technologies. At the macro level, Arny et al. (1998), Blasnik (1998), Brechling and Smith (1994) and Goldman et al. (1988) demonstrate the benefits of comprehensive retrofitting programmes. However, most studies tend to evaluate energy savings alone. At best, environmental emissions (usually in the form of CO2) are quantified, but the other potential benefits of domestic energy-efficiency programmes, such as improvements in health and comfort, tend to be omitted from any cost–benefit analysis. The chief difficulty, succinctly identified by Blasnik (1998), is that “although many of these benefits have been demonstrated to exist, most have never been fully quantified because of considerable methodological issues in assessing them”. The research presented in this paper attempts to advance the literature on the economic evaluation of domestic energy-efficiency programmes by carrying out a comprehensive evaluation of a range of costs and benefits using an example. It thereby develops a template for carrying out ex ante analyses of large-scale domestic energy-efficiency programmes. In so doing, it provides insights into the methodological difficulties and solutions for assessing the social efficiency of such programmes.

The research summarised in this paper has attempted to build on existing research on the economic evaluation of energy-efficiency projects by presenting a template for undertaking comprehensive cost–benefit analyses of domestic energy-conservation programmes. The case study chosen was a programme to retrofit the Irish housing stock with energy-conservation measures such that it would be brought up to the standards of the latest building regulations. The programme was subjected to cost–benefit analysis, the components of which include costs, energy savings, emissions’ reduction benefits, health benefits and comfort benefits. These costs and benefits were evaluated via an energy-assessment model of the housing stock and an associated cost–benefit model. While an attempt has been made to evaluate all the costs and benefits, there are a number of weaknesses in the analysis. Firstly, assumptions must be made about household behaviour (e.g. how will individuals react once energy-efficiency measures have been installed in their houses, i.e. it is necessary to predict the combination of comfort and savings on energy bills that will be chosen). Future energy prices cannot be predicted with certainty, nor can future developments in available technology. Health benefits are particularly difficult to calculate. Not only is it necessary to estimate the physical number of deaths and illnesses that result from inadequately heated houses, it is also necessary to choose appropriate coefficients for reduced risk of death and disease. Finally, the estimation of comfort benefits is less than ideal as it is based upon an estimate of the extent to which households will forgo savings on energy spend in exchange for comfort. A lower bound estimate is obtained which relies upon an assumption of perfect knowledge on the part of the householder. The above difficulties demonstrate that a perfect methodology for evaluating large-scale energy-efficiency programmes is not yet available. In addition, a positive evaluation is far from sufficient to ensure that such a programme is implemented for various reasons as shown by Clinch and Healy (2000d). Nevertheless, the results of this study are convincing enough to show (as have other studies) the clear net benefits to society of an effective household energy-efficiency programme. However, the extent to which research in the area of economic evaluation of energy-efficiency programmes is beneficial depends upon whether the programmes themselves can be effectively implemented.