AbstractEnergy supply plays an important role for most societies. However, depending on the development stage, local resources, system choice and several other factors, suitable energy supply solutions may differ from society to society. Optimal solutions may depend on the availability of energy technologies that take a long time to develop. For this reason, energy planning and policy formulation call for a comprehensive assessment of existing technologies, as well as unbiased evaluations of the need for new technology development considered appropriate for the future energy supply systems of individual societies.