Peculiarities of Electrical Design in Geothermal Power Plants

Abstract

Most engineers in the power industry are aware that one of the by-products in geothermal energy exploitation is hydrogen-sulfide gas (H2S). Besides smelling bad and causing rapid corrosion of iron and steel, H2S reacts with various materials commonly utilised in electrical and control systems installation including copper, silver, nickel-silver, cadmium, brass, bronze and phosphor-bronze. Therefore design of electrical systems in geothermal environments must stipulate extraordinary measures to protect electrical components from corrosion during the life of the plant. These protection measures are not confined to material selection. The presence of H2S in the atmosphere gives rise to a number of building, building services, control system and electrical reticulation system design considerations that are peculiar to geothermal power plants. This paper describes the common problems and commonlyapplied engineering solutions, and also describes one of the electrical design innovations that the team at Parsons Brinckerhoff has introduced on a recent geothermal project.