Electrical power generated directly from solar energy has been discussed, investigated and made practicable in a number of small-scale applications for many years. Environmental considerations now make it imperative to apply the technology to buildings. This Digest describes photovoltaic options and installations in relation to Standards and regulations, compatibility with other building elements, safety and ease of maintenance. It will help architects, designers of building components, specifiers and owners to identify the main issues and practicalities of using photovoltaic systems to supplement conventional means of electricity generation for buildings. 6 pages.