Optimal scheduling for power-intensive processes under time-sensitive electricity prices

LOTERO, IRENE; BASÁN, NATALIA P.; C. A. MÉNDEZ; GROSSMANN, IGNACIO E.; GOPALAKRISHNAN, AJIT

Barcelona

Simposio; 27th European Symposium on Computer Aided Process Engineering; 2017

The competitiveness of power-intensive industries is highly tied to their ability to adjust production according to time-sensitive electricity prices. A classic example are Air Separation Units (ASUs), where large, electric-power air compressors are used to reach cryogenic temperatures. Due to the volatility nature of the energy markets, there is significant opportunity to reduce production costs by scheduling production during the cheapest hours of the day. In this work, a mixed-integer linear model (MILP) model is presented based on a discrete-time scheduling formulation that allows modeling and optimizing operating decisions for any process under time-sensitive energy prices. The main goal is to find an optimal production schedule over a given time horizon that guarantees product demand satisfaction and that minimizes total energy cost. The novel formulation used to model transitions between operating modes results in a very efficient and robust model. The model is applied to a simplified industrial case The results show optimal solutions for the proposed methodology with modest computational effort.