Electrical Energy Storage: an introduction

1 IET StandardsMichael Faraday HouseSix Hills WayStevenageHertfordshireSG1 storage systems for Electrical installations are becoming increasingly common. This Technical Briefing provides information on the selection of Electrical Energy storage systems, covering the principle benefits, Electrical arrangements and key terminologies used. The Technical Briefing supports the IET s Code of Practice for Electrical Energy storage Systems and provides a good introduction to the subject of Electrical Energy storage for specifiers, designers and Energy storage : an introductionIET Standards Technical Briefi ngIET Standards Technical Briefi ngElectrical Energy storage : an introductionSupported by:Supported by:IET Standards ES Tech Briefing 102/06/2016 10.

2 39 The Institution of Engineering and TechnologyCONTENTSP ublication InformationPublished by The Institution of Engineering and Technology, London, United KingdomThe Institution of Engineering and Technology is registered as a Charity in England & Wales (no. 211014) and Scotland (no. SC038698). The Institution of Engineering and Technology 2016 This publication is copyright under the Berne Convention and the Universal Copyright Convention. All rights reserved. Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may be reproduced, stored or transmitted, in any form or by any means, only with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms of licences issued by the Copyright Licensing Agency.

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5 We would like to thank members of the IET Standards Technical Committee Electrical Energy storage Systems for their contribution to this introduction 12 Reasons and benefits 23 Selecting systems 54 Electrical arrangements 175 References and related documents 216 Terminology 221 The Institution of Engineering and Technology1 SECTION 1 IntroductionElectrical Energy storage systems (EESS) for Electrical installations are becoming more provide storage of Electrical Energy so that it can be used later. The approach is not new: EESS in the form of battery-backed uninterruptible power supplies (UPS) have been used for many years.

6 EESS are starting to be used for other purposes. There are several reasons behind the increasing use of EESS:(a) they make renewable Energy more effective by ensuring that the Energy that is generated by renewable sources is available when that Energy source is not available. EESS can be used either to ensure that all Energy generated can be used locally in addition to the grid supply or to provide total independence from the public supply.(b) they make Energy available during loss of the grid supply, enabling, for example:(i) 'controlled shutdown' of data centres and other computer and control systems to prevent corruption of stored data that would otherwise occur if the power was to be removed abruptly.

7 (ii) Electrical and electronic products and infrastructure to be used during power outages.(c) they allow for grid support services, including fast frequency response, demand and supply management, network constraints, and power quality management. These services could be aggregated over a number of sites and are not necessarily located on generation sites.(d) the falling cost of EESS, notably lithium ion Technical Briefing supports the forthcoming IET Code of Practice for Electrical Energy storage scope of this Technical Briefing is limited to EESS technology that is based on electrochemical batteries and their associated charging control and protection systems.

8 These are the predominant current and emerging technologies that are intended for use:(a) with common low voltage (LV) supplies in use in the UK; and(b) within Electrical installations that are not part of the public electricity supply The Institution of Engineering and TechnologySECTION 2 Reasons and OverviewTable outlines the principal benefits, with respect to both embedded generation and demand and availability of the public supply. TTable Principal benefits of Energy storage solutionsType of installation0 RINCIPAL BENE TS OF Electrical Energy STORAGE2 ELATING TO EMBEDDED GENERATION GENERATION FROM renewables2 ELATING TO DEMAND AND availability of the public supplyDwellingsAvailability of locally generated Energy , when the Energy source (daylight, wind) is not rural locations, independence of the public supply may be grid-demand power loads could be supplied during extended periods of supply outage.

9 This may include power for communications and data devices/device charging, media, LED lighting and heating control/ignition for non-electric heating rural or remote locations, independence of the public supply may be possible with local renewable Energy costs by charging OFF PEAK WHERE THE LOAD PRO LE is high at peak demand periods ( for homeworkers), subject to an appropriate CE premisesAvailability of locally generated Energy , when the Energy source (daylight, wind, CHP) is not providing grid-demand power loads could be supplied during extended periods of supply outage. This may include power for communications and data devices/device charging, media, LED lighting and heating control/ignition for non-electric heating Energy costs by charging OFF PEAK WHERE THE LOAD PRO LE is high at peak demand periods.

10 Subject to an appropriate The Institution of Engineering and TechnologyType of installation0 RINCIPAL BENE TS OF Electrical Energy STORAGE2 ELATING TO EMBEDDED GENERATION GENERATION FROM renewables2 ELATING TO DEMAND AND availability of the public supplyIndustrial premises key infrastructureOptimise the use of any locally generated Energy from renewable Energy costs by charging OFF PEAK WHERE THE LOAD PRO LE is high at peak demand periods, subject to an appropriate power for safety or mission critical functionality when the public supply is lost, until local (prime mover) generation etc.