This note DES 10, originally published in February 1996, was reviewed by Deo Prasad in November 2001. This summary page includes recent updates to the topic since publication. Architects are increasingly aware of the economic and ecological benefits of 'designing in' energy conservation measures during the design phase of new domestic and commercial building projects. Renewable energy technologies and corresponding design applications are producing energy efficient and ecologically sustainable design solutions as well as creating the germ for a new architectural aesthetic. This Note outlines the renewable energy supply systems and options available to architects – with specific reference to the integration of photovoltaic technology in architecture.