تاثیر یک محرک برای بهره وری انرژی در اقتصاد و محیط زیست: تجزیه و تحلیل منطقه ای تعادل عمومی قابل محاسبه

Sustainable development is a key objective of UK national and regional policies. Improvements in resource productivity have been suggested as both a measure of progress towards sustainable development and as a means of achieving sustainability. Making ‘more with less’ intuitively seems to be good for the environment, and this is the presumption of current UK policy. However, in a system-wide context, improvements in energy efficiency lower the cost of energy in efficiency units and may even stimulate the consumption and production of energy measured in physical units, and increase pollution. Simulations of a computable general equilibrium model of Scotland suggest that an across the board stimulus to energy efficiency there would actually stimulate energy production and consumption and lead to a deterioration in environmental indicators. The implication is that policies directed at stimulating energy efficiency are not, in themselves, sufficient to secure environmental improvements: this may require the use of complementary energy policies designed to moderate incentives to increased energy consumption.

Sustainable development is a key objective of UK government policies (Department of Environment [1]), is one of the outcome objectives of the Scottish Executive's Framework for Economic Development (Scottish Executive [2]), and is receiving increasing emphasis in a regional development context more generally. The Scottish Parliament re-affirmed its commitment to sustainable development in 2002 with the publication of a document (Scottish Executive [2]) setting out Scotland's approach to promoting sustainable development through the adoption of targets for 24 sustainability indicators (see also Scottish Executive [3]). Clearly the success of national sustainability programmes will depend upon policy delivered at the regional level. The region therefore appears to be the natural level on which to focus policy evaluation, a perspective that proves significant in our analysis. Resource productivity has been suggested as both a measure of progress towards sustainable development, and as a means of achieving sustainability (Cabinet Office [4]). The popular interpretation of resource productivity is ‘doing more with less’: that is, of reducing the material or energy requirements of economic activity. As we note below, there are many possible interpretations of resource productivity. However, the (untested) presumption appears to be that improving resource productivity will lower the burden on the environment. In this paper, we begin to explore the conditions under which this presumption would be expected to hold, and present some empirical evidence from an energy–economy–environment computable general equilibrium (CGE) model of the Scottish economy. In Section 2, we define resource productivity, summarise previous analyses and sketch our own analysis of the likely system-wide ramifications of a stimulus to energy efficiency. We outline our computable general equilibrium model of the Scottish economy in Section 3. In Section 4 we present the results of simulating an across the board stimulus to energy efficiency. We conclude in Section 5.

In this paper, we argue that predicting the environmental impacts of significant improvements in resource productivity requires a general equilibrium approach, since we would expect these to generate important system-wide output and substitution effects that tend to increase resource use, and act as countervailing influences to the direct effects of being able to ‘produce more with less’. In the case of Scotland, we find that an improvement in energy efficiency eventually increases energy consumption and pollution over time, since the positive output and substitution effects associated with lower effective energy prices outweigh the direct efficiency effect. This is almost certainly not what advocates of resource productivity would intend. In future research we plan to extend the present analysis in a number of respects. First, we shall explore the significance of our assumption that the energy efficiency stimulus is confined to a single region, through appropriate simulation of a multi-regional variant of the model we employ in this paper. Secondly, we shall examine the consequences of a more detailed modelling of energy markets in general, and renewable energy markets in particular. Thirdly, we shall specify energy efficiency policies in detail: the analysis of exogenous efficiency changes in this paper should be regarded as a prelude to assessing and evaluating policy impacts. We are confident, however, that the forces that we identify in this paper will continue to prove relevant in more complex systems. We would emphasise, though, that our analysis does not imply that policies designed to stimulate energy efficiency are misguided: rather, it implies that such policies cannot, in and of themselves, be relied upon to deliver environmental improvements. To ensure such improvements, policies promoting energy efficiency improvements may have to be combined with other energy policies that serve to inhibit any forces encouraging greater energy consumption.