The renewed interest in solar energy as a partial solution to the problem of supplying the future energy needs of the United States and the world has been sparked, in part, by advances in optical coating technology. In particular, thermal and direct conversion approaches are strongly dependent on coatings for optimum operational characteristics. Owing to the dilute nature of solar energy available on the earth's surface, the required collecting area is likely to be very large. The variety of solar energy conversion methods and applications currently being considered is reviewed. The role and rationale for coatings in the systems lead to coating requirements. A hypothetical model of solar energy implementation is presented, leading to a forecast of future requirements for the solar coating industry. Comparisons are made between 1973 production and future requirements.