Firsty, surface science plays a major role and makes major contributions to various areas of energy development and technology. Surface science related problems are listed in such fields or fossil, nuclear, fusion, and solar energy technologies Sècondly, the use of thermionic energy conversion (TEC) as a topping cycle for central station powerplants is a viable option for achieving greater efficiency and, therefore, substantial fuel savings. Higher efficiency can be achieved by lower collector work functions. Oxygen at a pressure of the order of 10^-6 Torr in the interelectrode space lowers the work function of the collector, improving the effidiency.