Preserving low cost electricity while improving the riverine environment: A case study of Ghana’s Akosombo hydro complex

This paper presents the strategy for development of a stochastic programming model of the operation and capacity additions to a large hydro/thermal electricity generation complex. The proposed model minimizes the incremental costs of operating the complex so as to return river flows to pre-dam patterns. The paper focuses on a representative year made up of wet and dry seasons far enough into the future to allow adjustment of thermal and hydro generating capacities and the initial level of the reservoir, but not the capacity of the reservoir itself. The model was run first to find the operating and investment strategies which minimize electricity costs, and then run so as to minimize cost subject to equating seasonal reservoir inflows to seasonal outflows - so called ldquorun of river, RORrdquo operation. Using data from Ghanapsilas Akosombo/Kpong complex, likely outcomes of the model are presented and compared, based on existing capacities of the system.