Seasonal and time of day dependent electricity costs in Sri Lankan power system, considering water value

Abstract

Electricity generation costs fluctuate significantly due to seasonal, daily and hourly variations in electricity demand and powerplant availability. Utility providers prioritise optimising overall generation costs while ensuring continuous and high- quality electricity supply. The scheduling of power plant dispatches follows Stochastic Dual Dynamic Programming (SDDP) principles to maximise operational efficiency. Unlike thermal power plants, the evaluation of water value for hydropower plants introduces complexity in generation cost calculations. This research introduces novel approaches for estimating water value. These approaches include assigning a zero value to water, as well as proposing the generation cost of the most expensive thermal power plant in the daily load curve and the weighted average value of variable thermal power plants as optimal methods for water value estimation. The study accurately estimates seasonal and time-of-day-dependent electricity costs using advanced economic dispatch techniques and refined water value estimation methodologies. Furthermore, it explores the comparative water values between power generation and agriculture, enhancing decision-making processes. Focused on the Sri Lankan power system, this research contributes valuable insights into optimising electricity generation strategies amidst dynamic operational conditions.