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Rachid Yazami
Draper prize winner, Energy Research Institute (ERIAN),Nanyang Technological University, Singapore

For a broad public lithium ion batteries (LIB) are known for their daily utilization in portable electronics such as in smartphones, tablets, PCs, cameras, toys…Less commonly known is LIB application in electro-mobility (EM) and in energy storage systems (ESS). In fact, EM and ESS are relatively recent market developments as they concern less visible systems such as electric vehicles, power plants and buildings, yet EM and ESS are the fastest growing market applications of LIB. There are about 20 billion LIB cells used worldwide in 2016. Market forecasts puts it at 6.8 billion the amount of LIB to be produced in 2016, an over 20% increase from 2015. The reasons behind LIB outstanding commercial success is due to their excellent performances when compared to other rechargeable battery systems. LIB store up to 5 times more energy per weight and volume units and deliver as much power. Their calendar life can exceed 10 years in some applications while their cost is dropping each year due to scale effect and competition. Moreover LIB demonstrate a good safety record despite the highly publicized and unfortunate Samsung Galaxy Note 7 case.

In the future energy transition LIB will play a major role in EES as they will significantly contribute to reducing greenhouse gas emission owing to high energy efficiency LIB provide. Electrical energy has this in particular that production and consumption should be equal at any time. Conventional electric power plants such thermal (coal, gas, oil) and nuclear better operate at constant power output. However consumption is variable by nature from day to night, upon weather changes and surges in demand. To balance between production and consumption energy storage is commonly used. Among various ES technologies, those based on LIB is the fasted growing one as LIB provide more flexibility, and shorter response time, while being economical. Applications include 1) regulation (frequency, voltage support, load levelling, power quality); 2) arbitrage (store energy when cheap), 3) back-up and reserve (UPS, power continuity), 4) black start (active reserve to re- start a power generator), 5) investment deferral (avoid infrastructure investment) and, 6) grid independent power supply (in areas not connected to grid such as rural community, stations powered by solar energy). In the sustainable clean energy space (solar, wind, waves, hydroelectric) ES will also play a major role in the energy efficiency because of the intermittent nature of these energy generation systems. For instance solar and wind energy power output depends on whether sun is shining or not and wind is blowing or not. LIB based ESS are among best choice considering outstanding performances in terms of energy and power density, calendar life, safety and costs. LIB overall worldwide production is expected to grow from 60 GWh in 2015 to 215 GWH in 2025, which is about 15% annual growth per year. ESS will play a driving force in this future growth as humanity is moving towards cleaner energy to save environment and reduce global climate warming.

Rachid Yazami, Draper prize winner, Energy Research Institute (ERIAN), Nanyang Technological University, Singapore