The Influence of Environmental Constraints on the Water Value

• Main Authors: Ignacio Guisández, Juan I. Pérez-Díaz, José R. Wilhelmi
• Format: Article
• Language: English
• Published: MDPI AG 2016-06-01
• Series: Energies
• Subjects: water value; minimum environmental flows; maximum ramping rates; stochastic dynamic programming; mixed integer linear programming
• Online Access: http://www.mdpi.com/1996-1073/9/6/446

The establishment of more severe hydrological environmental constraints, usually as seasonal minimum flows (ϕ) and maximum ramping rates (ρ), on hydropower operation is a growing trend. This paper presents a study on the influence of ϕ and ρ on the water values (WV) of a real hydropower plant that participates in the Spanish day-ahead electricity market. For this purpose, a master-slave algorithm, based on stochastic dynamic programming (SDP) and deterministic mixed integer linear programming (DMILP), is used on a real hydropower plant. The master module, based on SDP, has a yearly planning period with weekly time steps and considers three state variables: stored water volume in the reservoir at the beginning of each week; weekly water inflow; and average weekly energy price. The slave module, based on DMILP, has a weekly planning period with hourly time steps and considers many features of the hydropower plant operation, such as: start-up costs, evaporation, wear and tear costs, etc. The results indicate that WV of a hydropower plant are very sensitive to the presence of these constraints; ϕ especially during the wettest season and ρ during the driest one. As the severity of ϕ and ρ increase, WV increase and decrease, respectively.