Battery Capacity of Deferrable Energy Demand

TL;DR

This paper explores how a group of deferrable energy loads can function as a controllable battery, analyzing capacity limits and fundamental trade-offs between different battery parameters.

Contribution

It derives bounds on the achievable battery capacity and characterizes the trade-offs between capacity, charge, and discharge rates for deferrable loads.

Findings

Identifies fundamental trade-offs between battery parameters.

Derives bounds on the maximum achievable capacity.

Shows conflicting state trajectories for high-rate energy absorption and release.

Abstract

We investigate the ability of a homogeneous collection of deferrable energy loads to behave as a battery; that is, to absorb and release energy in a controllable fashion up to fixed and predetermined limits on volume, charge rate and discharge rate. We derive bounds on the battery capacity that can be realized and show that there are fundamental trade-offs between battery parameters. By characterizing the state trajectories under scheduling policies that emulate two illustrative batteries, we show that the trade-offs occur because the states that allow the loads to absorb and release energy at high aggregate rates are conflicting.