Advances in steam turbines for solar thermal and integrated solar combined cycle power plants

This paper presents an overview of developments in steam turbines in general with particular application to match concentrating solar thermal (CST) sources.

The design of solar steam generator which has a parabolic output profile is first presented. Technologies for maintaining steady steam inflow into the steam turbine, viz., hybridization of sources like integrated solar combined cycle (ISCC) and thermal energy storage (TES), cogeneration, trigeneration, etc., are explored.

The developments in the steam turbine consist mainly of upgraded materials to operate at higher steam inlet temperature and pressure, ungraded energy efficiency through 3-dimensional computation fluid dynamics (CFD) design, increased fatigue life to withstand large number of cyclic operations, increased dynamic response and automation in manufacture. It is concluded that while 3-d designed steam turbines for elevated temperatures fulfill most requirements of CST power systems, fatigue life improvement and better energy efficiency at part load, needs to be addressed.