The 'Virtual Battery' - Operating an Aluminium Smelter with Flexible Energy Input

Abstract

TRIMET Aluminium SE operates four smelters in Western Europe. TRIMET has investigated power modulation and opportunities to provide services to the energy grid for several years. The primary aim has been to stay competitive in a geographic zone with above world-average energy prices as well as having to deal with high volatility in energy prices caused by renewable, non-baseload energy sources. Recent work has seen the implementation of Shell Heat Exchanger (SHE) technology on 12 pots at TRIMET's plant in Essen, Germany. The heat exchangers are capable of boosting sidewall heat extraction or acting as an insulator depending on active air flow or not. The pots have comfortably maintained heat balance with stable ledge when operated within 150 to 180kA for up to 48h. Greater control of heat loss has also enabled operating voltages to be significantly reduced. By being able to operate significantly above or below the conventional design amperage, the smelter can operate as a 'Virtual Battery' to the grid.