Since the mid-seventies, electric utilities were faced with escalating construction costs, growing environmental plus siting constraints and increasing uncertainty in demand forecasting. To cope with the increasing demand for energy services, utilities can either invest in supply-side options (new generation, transmission and distribution facilities) or in demand-side options. Demand-side options include, policies, programmes, innovative pricing schemes and high-efficiency end-use equipment (equipment providing the same or better level of services but using less energy or peak power). Recent experience in both North America and Europe show that demand-side options are usually cheaper and less damaging from the environmental point of view, and also their potential can be tapped in a shorter term than other supply-side options. This workshop was directed at the discussion and analysis of cost-effective methodologies to achieve the supply of electric energy services at minimum cost and minimum environmental impact. The programme included new developments in power planning models which can integrate both supply-side and demand-side actions. Quantitative assessments of the environmental impact of different supply-demand strategies were analyzed. Planning models which deal with uncertainty and use multicriteria approaches were presented. Case studies and experiments with, innovative concepts carried out by utilities in several countries were discussed. Load modelling and evaluation of demad-side programmes was analyzed. Additionally, the potential for electricity savings in the industrial, commercial and residential sectors was presented. New research directions covering planning models, programmes and end-use technologies were identified.