This module will relate to the materials issues related to sustainable environmental technologies. The module will be based on the concept of a Hydrogen Economy and the production of the hydrogen will be from clean energy sources such as wind or solar. The materials issues relating to these will be described and discussed. The hydrogen will be produced largely by electrolysis and materials issues relating to this technology will be considered. Hydrogen from biomass will also be examined. Materials for hydrogen storage and transmission will be discussed. Fuel cells will be considered in depth and more general issues such as energy efficiency will be discussed, focusing on soft and hard magnets. The energy content of materials will also form a part of this module.