Use of levelized costs and screening curves to select the optimum generation mix for sri lankan electricity sector

Abstract

Sri Lanka is facing problems in selecting optimum electricity generation mix due to the environmental pressures and economic constraints. With limited hydro resources which have already been harnessed up to maximum level, the only options available are diverting to alternative sustainable energy sources. In this context this study assesses the available generation alternatives for Sri Lanka in terms of financial, social and environmental constraints by using levelized generation cost and screening curves mechanism. Each generation option is thereby selected on analytical hierarchical process (AHP) technique based on four attributes of levelized cost, energy security, environment damage cost and social benefits and thereby optimum generation mix is decided. The identified generation options have been analyzed for next twenty year of life span for calculation of levelized generation cost, energy security and technological constraints, environmental damage cost and social benefits with analytical hierarchical process technique. Research findings show that coal and combined cycle diesel power stations are suitable for base load and high capacity operations at 80% to 90% loading at higher energy security with maximum social benefits. However, hydro and wind power stations are suitable for running at 30% to 40% loading at lowest levelized generation by minimizing environmental damage cost but not base load operations. Presently, Hydro power stations are running for base load operations which have been proven to be re-evaluated in this study despite the proposed generation mix does not include solar power generation due to many factors. Therefore, it is recommended to run existing hydro power generators at 30% to 40% loading at base load operations while coal and combined cycle diesel generators to be run at 80% to 90% throughout the clock. The methodology employed and the policies derived can be used as guides to similar types of research in other countries as well.