World energy demand is expected to increase to several times its current level over the next 50 years. Much of this energy will come from fossil fuel, a finite resource, which moreover generates carbon dioxide, a cause of global warming. The incentive to develop other, renewable forms of energy is therefore strong, but how can we be sure that our expectations for the future form a rational basis for determining energy policy? The scenario planning technique does not attempt to predict the future, but offers a variety of visions against which current actions and policies can be tested. To guide the move towards a more sustainable future it is also important to be able to monitor our progress. The use of sustainability metrics, tailored to a particular purpose, and relating to resource efficiency, environmental protection, economic benefits and social development, is a way of quantifying this progress. The set of indicators illustrates the 'sustainability footprint' of an enterprise.