First and Second Law Analisys of a Hydro Storage with Respect to the Environmental Impact of an Energy System

Abstract

When a regional electrical energy demand is far from stationary and features daily peaks, convenient ways to operate the energy system are by peak turbogas plants or by energy recovery from storage systems. The present tendency is to provide for large storage capacities, since peak plants are rather expensive; the only feasible store proven so far is the hydro storage, which plays the role of an important water resource for energy uses. In this paper the thermodynamic and environmental benefits of operating hydro stores versus peak plants as turbogas will be demonstrated under certain circumstances, adding extra convenience to the choice of large storage capacities, for which lower first and operating costs are already ascertained. The method that is followed is a purely thermodynamic one, consisting in a first and second law analysis of dissipations.