UPTEC ES11 031 Examensarbete 30 hp December 2011 Flywheel energy storage a conceptual study Rickard Östergård Abstract Flywheel energy storage - a conceptual study Rickard Östergård Teknisk- naturvetenskaplig fakultet UTH-enheten This master thesis was provided by ABB Cooperate Research in Västerås. This study has two major purposes: (1) to identify the characteristics of a flywheel energy Besöksadress: storage system (FESS), (2) take the first steps in the development of a simulation Ångströmlaboratoriet Lägerhyddsvägen 1 model of a FESS. Hus 4, Plan 0 For the first part of this master thesis a literature review was conducted with focus Postadress: on energy storage technologies in general and FESS in particular. The model was Box 536 751 21 Uppsala developed in the simulation environment PSCAD/EMTDC; with the main purpose to provide a working model for future studies of the electrical dynamics of a FESS. Telefon: 018 – 471 30 03 The main conclusion of the literature review was that FESS is a promising energy Telefax: storage solution; up to multiple megawatt scale. However, few large-scale installations 018 – 471 30 00 have so far been built and FESS is not a mature technology. Therefore further research and development is needed in multiple areas, including high strength Hemsida: composite materials, magnetic bearings and electrical machines. The model was http://www.teknat.uu.se/student implemented with the necessary control system and tested in a simulation case showing the operational characteristics. Handledare: Frans Dijkhuzien Ämnesgranskare: Hans Bernhoff Examinator: Kjell Pernestål ISSN: 1650-8300, UPTEC ES11 031 Sponsor: ABB SAMMANFATTNING Detta examensabete har två huvudsyften: (1) att identifiera och beskriva de ingående komponenterna hos ett energilagringssystem med svänghjul (Flywheel Energy Storage System, FESS), (2) ta första stegen i utvecklingen av en simuleringsmodell. Första delen av examenarbetet genomfördes genom en litteraturstudie med fokus på energilagringsteknik i allmänhet och FESS i synnerhet. Modellen är utvecklad med hjälp av simuleringsprogrammvaran PSCAD/EMTDC med huvudsyftet att uveckla en fungerande modell för framtida studier av den elektriska dynamiken hos ett FESS. Den viktigaste slutsatsen av litteraturstudien är att FESS är en lovande energilagringsteknik med kapacitet upp till flera megawatt. Hittills har endast ett fåtal storskaliga installationer byggts, vilket betyder att FESS inte är en mogen teknik. Det behövs därför vidare forskning och utveckling inom flertal områden; bland annat inom materialvetenskap, magnetiska lager och generatorer. Simuleringsmodellen har implementerats med nödvändiga styrsystem och testats i ett simuleringscase som visar de viktigaste egenskaperna hos ett FESS. TABLE OF CONTENTS 1 INTRODUCTION ........................................................................................................................ 3 1.1 BACKGROUND ........................................................................................................................ 3 1.2 SMART GRID .......................................................................................................................... 3 1.3 AIM ........................................................................................................................................ 4 2 ELECTRICAL ENERGY STORAGE SYSTEMS (ESS) ............................................................ 5 2.1 APPLICATION IN ELECTRICAL GRIDS ...................................................................................... 5 2.2 ENERGY STORAGE TECHNOLOGIES ........................................................................................ 6 2.2.1 Pumped hydro (PHS) ................................................................................................... 7 2.2.2 Compressed air energy storage (CAES) ................................................................... 7 2.2.3 Battery energy storage (BESS) .................................................................................. 8 2.2.3.1 Sodium Sulphurs Batteries ................................................................................... 8 2.2.3.2 Lithium-Ion Batteries .............................................................................................. 8 2.2.3.3 Lead-acid batteries ................................................................................................. 8 2.2.3.4 Flow batteries ........................................................................................................... 9 2.2.4 Super conducting magnetic energy storage (SMES) .............................................. 9 2.2.5 Supercapacitors......................................................................................................... 10 2.3 TECHNOLOGY SUMMARY ...................................................................................................... 10 3 FLYWHEEL ENERGY STORAGE ........................................................................................... 11 3.1 GENERAL ............................................................................................................................. 11 3.2 HISTORY .............................................................................................................................. 11 3.3 FLYWHEEL BASICS................................................................................................................ 11 3.3.1 Geometries and material ............................................................................................. 12 3.4 FLYWHEEL SYSTEMS COMPONENTS ...................................................................................... 14 3.4.1 Electrical machine........................................................................................................ 14 3.4.2 Bearings ....................................................................................................................... 14 3.4.3 Housing ........................................................................................................................ 15 3.4.4 Power electronic interface ........................................................................................... 16 3.5 RANGE OF CAPACITIES ......................................................................................................... 16 3.6 ENVIRONMENTAL ISSUES ...................................................................................................... 16 3.7 COMMERCIALLY AVAILABLE FLYWHEEL SYSTEMS .................................................................. 16 3.7.1 Beacon Power ............................................................................................................. 17 3.7.2 Vycon Energy .............................................................................................................. 18 3.7.3 Piller ............................................................................................................................. 18 3.7.4 Active Power ................................................................................................................ 19 3.7.5 Market summary .......................................................................................................... 19 3.8 SUMMARY ............................................................................................................................ 20 4 MODEL DESIGN ...................................................................................................................... 21 4.1 SCOPE ............................................................................................................................... 21 4.2 MODEL DESCRIPTION ........................................................................................................... 21 4.3 SINUSOIDAL PULSE WIDTH MODULATION ............................................................................... 21 4.4 D-Q-0 TRANSFORMATION .................................................................................................... 22 4.5 MOTOR/GENERATOR ............................................................................................................ 23 4.5.1 Machine-side VSC control strategy ............................................................................. 24 4.5.2 Grid connected VSC Model ......................................................................................... 26 4.5.3 Grid-side VSC control strategy .................................................................................... 27 4.6 FLYWHEEL ........................................................................................................................... 28 5 SIMULATION ............................................................................................................................ 29 5.1 CASE STUDY ........................................................................................................................ 29 5.2 SIMULATION RESULTS .......................................................................................................... 31 6 CONCLUSIONS AND DISCUSSION ....................................................................................... 32 7 RECOMMENDATIONS FOR FUTURE WORK ....................................................................... 33 8 ACKNOWLEDAGEMETS ........................................................................................................ 34 9 REFERENCES.........................................................................................................................