A non-linear convex cost model for economic dispatch in microgrids

TL;DR

This paper introduces a convex non-linear cost model for microgrid economic dispatch that accounts for energy storage degradation and renewable intermittency, improving cost estimation accuracy.

Contribution

It develops a convex non-linear degradation cost model based on semi-empirical equations, suitable for optimization in microgrid dispatch problems.

Findings

Model accurately captures seasonality trends in data.

It reduces total fuel costs compared to conventional methods.

Proves convexity of degradation cost models under certain conditions.

Abstract

This paper proposes a convex non-linear cost saving model for optimal economic dispatch in a microgrid. The mod-el incorporates energy storage degradation cost and intermittent renewable generation. Cell degradation cost being a non-linear model, its incorporation in an objective function alters the convexity of the optimization problem and stochastic algorithms are required for its solution. This paper builds on the scope for usage of macroscopically semi-empirical models for degradation cost in economic dispatch problems and proves that these cost models derived from the existing semi-empirical capacity fade equations for LiFePO4 cells are convex under some operating condi-tions. The proposed non-linear model was tested on two data sets of varying size which portray different trends of seasonality. The results show that the model reflects the trends of seasonality existing in the data sets and it mini-mizes the total fuel cost globally when compared to conventional systems of economic dispatch. The results thus indicate that the model achieves a more accurate estimate of fuel cost in the system and can be effectively utilized for cost analysis in power system applications.