Emulating Batteries with Flexible Electricity Loads poster.pdf

We investigate the ability of a 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.