Terrajoule can use any of the available third-party concentrator technologies: Parabolic trough; heliostat/tower; linear fresnel (CLFR).
Terrajoule exploits an old-fashioned technology: “Universal Unaflow” reciprocating steam piston engine technology that reached its historical pinnacle in the 1930s.
Since it is impractical to store gaseous steam for later use, the steam is condensed into the mass of water where its energy is stored. When needed, the stored energy flashes the water back to steam.
http://www.terrajoulecorp.com/unexpe.../how-it-works/