# A Lagrangian Policy for Optimal Energy Storage Control

## TL;DR

This paper introduces a millisecond-level look-ahead control algorithm for energy storage that is significantly faster than existing convex optimization methods, maintaining optimality and providing insights for system-wide control design.

## Contribution

The paper proposes a novel Lagrangian-based control algorithm that achieves constant space complexity and linear runtime, enabling ultra-fast energy storage management.

## Key findings

- Runs up to 100,000 times faster than convex optimization solvers.
- Achieves the same control results as state-of-the-art methods.
- Provides theoretical insights for centralized and distributed energy storage control.

## Abstract

This paper presents a millisecond-level look-ahead control algorithm for energy storage with constant space complexity and worst-case linear run-time complexity. The algorithm connects the optimal control with the Lagrangian multiplier associated with the state-of-charge constraint. It is compared to solving look-ahead control using a state-of-the-art convex optimization solver. Simulation results show that both methods obtain the same control result, while the proposed algorithm runs up to 100,000 times faster and solves most problems within one millisecond. The theoretical results from developing this algorithm also provide key insights into designing optimal energy storage control schemes at the centralized system level as well as under distributed settings.