A reasonable system capacity allocation scheme is basis for the utilization of renewable energy. Firstly, based on environment of desert areas, a capacity optimization model of WPTP hybrid system is established. Then, to study the substitution of pumped storage units to certain thermal power units in the system, a comparative example of WPT power generation hybrid system is set. Finally, the capacity configuration results and indexes are analyzed to verify the advantages of pumped storage as an alternative to thermal power.