Saudi Arabia has enormous oil resources. At the same time, the Kingdom has other resources, notably solar energy that may figure in future supplies of electricity. In the past several years, considerable operational experience has been gained throughout the world in the implementation of renewable energy systems of types that would be relevant to the Kingdom. This paper reviews the nature of this experience and applies it in a quantitative assessment of the costs, savings, and environmental benefits of renewable energy conducted as a part of an electric utility integrated resource planning (IRP) project in the Kingdom. Integrated resource planning is an approach that systematically evaluates potential electricity supply and demand-side resources with the aim of developing a plan that provides energy services to customers at the least societal cost. The analysis summarized in this paper has shown that, when some of the non-market benefits of renewable energy are also included in the assessment of their overall costs and benefits, a supply expansion plan that includes wind and solar resources can provide energy services for the Kingdom at a lower societal cost than a "Business-as-usual" plan utilizing only fossil-fueled generating resources. (c) 2005 Published by Elsevier Ltd.