The presentation will try to show that solar thermal energy is the only presently proven truly renewable energy source that could in the long run provide the major fraction of the U.S. energy requirements. The presentation will also show that there are important applications that have been overlooked until now, for which a properly designed solar thermal power plant already has a competitive advantage over nuclear power and clean coal technology. These applications include supply of intermediate load electricity, and especially supply of instantaneously variable controllable electricity that is essential for controlling the grid. If one includes the cost of the final CO2 sequestration, solar thermal electricity is already cheaper than electricity generated from a coal power plant. Solar thermal energy is, therefore, the best and most cost effective technology for large-scale reduction of CO2 emissions. Solar thermal energy has also advantages for co-production of electricity and desalinated water. The presentation will also discuss future research needs.