Multi-objective optimization for hybrid sizing and objective function development

Abstract

This project introduces and develops Carbon Emissions Offset (CEO) as an objective function for hybrid power plant (HPP) design and operation optimization. CEO is modeled and implemented in HyDesign, a hybrid power plant optimization tool. The HPP sizing optimization in HyDesign is retrofitted so that CEO and Cost of Valued Energy (COVE) are jointly optimized. In addition, the energy management system (EMS) optimization is modified to allow for multi-objective optimization of emissions offsets and revenue, where the CEO objective function is adapted into various surrogate models made applicable to linear programming. Trade-offs between the objectives are analyzed for a hypothetical yet realistic hybrid power plant, comprised of an offshore wind farm and lithium-ion battery, that services western Denmark. Despite differences in battery behavior for tested HPP designs under three CEO surrogate models, overall trade-offs between revenue and lifetime emissions offsets are similar. Sizing optimization results also suggest similar trade-off patterns between COVE and CEO for a wind farm that assumes different turbine sizes. Further research could consider broader applications of CEO, e.g., to energy equity research or other optimization problem scenarios. The CEO objective function as presented here can be further developed to model more complex market structures and electricity trading schemes.