Optimizing Wellfield Operation in a Variable Power Price Regime.

Area of Science:

• Environmental Engineering
• Water Resource Management
• Optimization Theory

Background:

• Wellfield management traditionally focuses on energy efficiency (EFP) but is shifting due to deregulated power markets and renewable energy integration.
• Increasing price variability in power markets necessitates a management objective focused on minimizing operational costs rather than just energy consumption.

Purpose of the Study:

• To develop and apply a framework for optimizing wellfield operations to minimize electricity costs under variable power prices.
• To quantify potential cost savings achievable through flexible pumping strategies considering the energy footprint-pumping rate relationship and storage capacity.

Main Methods:

• A coupled well and pipe network model was used to establish the energy footprint of pumped water (EFP) as a function of pumping rate (Q).
• Stochastic Dynamic Programming (SDP) was employed to minimize the total operating cost of a wellfield-storage-demand system over a 2-year period.
• The SDP model incorporated hourly water demand, Danish power market prices, and constraints on storage capacity and demand fulfillment.

Main Results:

• The baseline scenario demonstrated minor cost savings of up to 10% with flexible wellfield operation.
• Scenarios with optimized EFP-Q relationships and higher pumping rates yielded greater savings, reaching up to 40% in one case.
• Key factors influencing cost savings include the EFP-Q relationship, maximum pumping rate, and available storage capacity.

Conclusions:

• Flexible wellfield operation, guided by variable electricity prices and system constraints, offers significant potential for reducing operational costs.
• The study highlights the importance of considering the dynamic interplay between energy costs, pumping rates, and storage in wellfield management.
• Adapting wellfield management strategies to market dynamics and technological capabilities is crucial for efficient water resource utilization.