Mine operations as a smart grid resource: Leveraging excess process storage capacity to better enable renewable energy sources

Abstract

The evolution of the electrical grid requires flexibility in electricity consumption. Given the tremendous amount of electricity consumed by mineral processing, these facilities could become a grid asset if they can leverage sources of flexibility. Shifting facility electricity consumption to limit demand and be predictable is valuable for grid management and stability. Enhanced stability from demand side management allows for the increased penetration of de-stabilizing intermittent renewable energy onto the grid. Two case studies of untapped mining facility flexibility are examined. While facilities generally try to maximize ore throughput, de-watering represents one source of flexibility due to the holdup capacity of the water table itself and storage tanks to which the water is pumped. A second source of flexibility is intermediate product transportation with storage capabilities at each end. By developing predictive automation algorithms, these holdup capacities can be effectively leveraged. This makes the facility able to respond to grid signals, which can save on demand charges, while also becoming an asset to the grid. This work uses real, facility-level power data and presents a novel automation algorithm for both predicting facility peak demand and proactively automating the de-watering and intermediate product transportation for peak shaving. De-watering costs are cut by 10% ($570,000) and slurry pumping costs are cut by 36% ($180,000) annually.