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Grid Connected Large-Scale Energy Storage

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Grid Connected Large-Scale Energy Storage Grid connected large-scale energy storage Literature review regarding present technology and application, with a complementary case study that investigates the profitability of storage within a wind farm Per Skoglund Master of Science in Energy Engineering, 300 hp Master thesis, 30 hp EN1729 Abstract In the transition from traditional power plants to more environmentally friendly alternatives will generate a need for more flexibility in production, transmission and consumption. Energy storage can be provide the flexibility that are required to continue to have a robust and stable electrical system. The purpose of this report is to give an overview of the electrical energy storage technologies. The classification of energy storage technologies used in this report is mechanical, chemical and electrical. In these three categories were ten different technologies presented with function, advantages, disadvantages, degree of maturity and research area for each technology. The distribution between the globally operational energy storage technologies were presented. Also the framework and regulations for actors to own and operate an energy storage in Sweden. This review was complemented with a case study about connecting a lithium ion battery system to a wind farm. The case investigated the profitability for 20 MW wind farm with a 12 MW and 18 MWh energy storage system for a five and ten-year period. The utilization of the storage was optimized with What’s best for three different investment cost. The review were done in order to answer: what is the futures energy storage technology?, what applications can be replaced by energy storage for an electricity producer? and what will the effects be of the new actor Aggregator? The result from comparing three different prices for lithium ion batteries resulted in a non-profit scenario for all the cases in a five-year period. There were a maximum, minimum and predicted futuristic price, which generated a loss of 731, 220 and 76.6 MSEK for respective case. Only the futuristic price for a ten-year period indicated an profit. The conclusion that can be drawn from this case study is that energy storage is too expensive and the extra income from utilization of the energy storage is not enough to motivate an energy storage investment. There are not a single technology that possesses all of the required properties for the applications. In the future there will be a combination of technologies to cover all the applications. For the seasonal storage pumped hydro and compressed air are most promising technologies. The flywheels and supercapacitors can contribute with short powerful burst of energy that are needed for power quality and operating reserves. For the more wide range application such as power fleet optimization and integrate the renewable energy production, batteries in form of lithium ion battery and sodium-sulfur battery will most probably be used. For electricity producers energy storage can replace existing solutions. Instead of using diesel generators for black start services, an battery can be used. Also the power quality could be enhanced with batteries acting as filters. The process can be more utilized in a more efficient way with an energy storage. The aggregator actor gathers small variable load from e.g several houses and participate on the electricity market. This actor will level out the differences in power demand during the day. It will reduce the losses and reduce the need for grid investments in both the transmission and distribution networks. It would also generate more available frequency reserves and probably change how the market is paying for the generated benefits. i Sammanfattning I en övergång från konventionellt planerbar elproduktion till ett elsystem med en hög andel intermittent, väderberoende elproduktion uppkommer ett nytt behov av flexibilitet i produktion, överföring och konsumtion. Energilager kan utgöra en viktig del av den flexibilitet som krävs för ett fortsatt robust och stabilt elsystem. Syftet med examensarbetet är att ge en överblick över de tillgängliga elektriska energilagringsteknikerna. Energilagringsteknikerna är kategoriserade utifrån hur de lagrar energin, mekaniskt, kemiskt eller elektriskt. I de här tre kategorierna presenteras tio teknikers funktion, fördelar, nackdelar, mognadsgrad och forskningsområden. Fördelningen mellan den globalt operativa energilagringstekniken med avseende på effektkapacitet presenteras samt de lagar och förordningar som gäller i Sverige för de olika aktörerna. Sammanställningen komplimenterades av en fallstudie där ett litium-jonsystem placerades inom en 20 MW vindpark. Fallstudien undersökte lönsamheten för ett batteri på 12 MW och 18 MWh för en fem- samt tioårsperiod. Användningen av energilagret optimerades med What’s best för tre olika investeringskostnader. Sammanställningen genomfördes för att svara på följande frågor. Vilken är framtidens energilagringsteknik?, Vilka användningsområden kan energilagring användas till för elproducenter? och Vilka effekter kommer den nya aktören aggregator att medföra? Resultatet från fallstudien visar att de tre investeringskostnaderna för litium-jonbatterierna resulterade i bristande lönsamhet för femårsperioden. Det var ett maximalt pris, minimalt pris samt ett futuristiskt pris och alla resulterade i en förlust för 731, 220 och 76.6 MSEK för respektive fall. Dock indikerades en lönsamhet med ett futuristiskt batteripris för en tioårsperiod. Fallstudien fastslog att energilagring är för dyrt och de extra inkomsterna som fås genom användningen av det inte är tillräcklig för att motivera en investering. Det finns inte en teknik som besitter alla nödvändiga egenskaper för att täcka in samtliga användningsområden. I framtiden kommer det vara en kombination av tekniker som tillsammans täcker in alla användningsområden. För säsongslagring kommer troligen pumpkraftverk och tryckluftslagring att användas. För de kortare och mindre pulserna av energi som krävs för frekvenshållning och elkvalité kommer troligen svänghjul och superkondensatorer att användas. För de mer övergripande användningsområdena som att integrera förnyelsebar produktion och för att optimera produktionen kommer litium jon och natrium-svavel batterier troligen att användas. För elproducenter kan energilagringen ersätta befintliga lösningar. Istället för att använda dieselgeneratorer som reservkraft, skulle man kunna använda batterier. Man skulle även kunna köra processen mer optimalt med ett energilager. Aggregatorn samlar små variabla laster för att medverka på elmarknaden. Aktören kommer troligtvis bidra med minskade effekttoppar och en mer jämn fördelning av effektuttaget från nätet. Det kommer att resultera i minskade överföringsförluster och minskat behov av investeringar för transmissions- och distributionsnätet. Det kommer också finnas flera effektreserver för frekvenshållningen samt att prissättningen av de andra fördelarna med energilagringen kommer troligen att förändras. ii Preface and acknowledgment This master thesis of 30 hp completes my studies for the degree Master of Science in Energy Engineering at the department of Applied Physics and Electronics at Umeå University. The work was done with Pöyry Sweden AB during the period 2017-01-16 to 2017-06-04. First I want to thank my supervisor at the university Jan-Åke Olofsson. I also want to thank Mats Wang-Hansen who was my supervisor at Pöyry for interesting discussions and guidance. I’m grateful to the publishers American Association for the Advancement of Science (AAAS) and Luo, Xing who gave me permission to use their figures. Umeå, May 2017 Per Skoglund iii Contents 1 Introduction 1 1.1 Purpose . .1 1.2 Research questions . .2 1.3 Methods . .2 1.4 Delimitations . .2 2 The electrical grid 3 2.1 Electricity market . .3 3 Framework and regulations for owning and utilization of energy storage 5 3.1 Grid owner . .5 3.2 Electricity producer . .6 3.3 Third party . .6 4 Electrical energy storage technologies 8 4.1 Mechanical . .8 4.1.1 Pumped hydro storage . .8 4.1.2 Compressed air storage . 10 4.1.3 Flywheel energy storage . 11 4.2 Chemical . 12 4.2.1 Lead acid batteries . 13 4.2.2 Lithium ion battery . 14 4.2.3 Sodium-Sulfur batteries . 15 4.2.4 Redox Flow battery . 17 4.2.5 Hydrogen storage with fuel cell . 18 4.3 Electrical . 19 4.3.1 Capacitors and supercapacitor . 19 4.3.2 Superconducting magnetic energy storage . 20 5 Operational power and degree of maturity of present energy storage technologies 21 6 Energy storages applications 23 7 Energy storage cost breakdown 27 8 Summary and future trends for the energy storage technologies 28 9 Case study 30 9.1 Method . 31 9.2 Results . 33 9.3 Discussion . 36 iv 9.3.1 Method . 36 9.3.2 Results . 37 9.4 Future work . 39 10 General discussion 40 11 Conclusions 42 11.1 Case conclusion . 42 References 43 A Tariffs A.1 B Battery prices B.1 C Annual cycles C.1 v 1 Introduction The entire energy sector is without a doubt dependent of fossil fuels but more environmentally sustainable options are advancing in the shape of renewable energy. The global investments in renewable energy 2015 were $285.9 billion, which is the highest annual investment so far [1]. The traditional energy sources are more versatile and more controllable, while energy production from renewable energy such as wind and solar power coincide more with the local weather. A problem with electricity is that in the same moment it is produced it must be consumed. Therefore it must exist a balance on the electrical grid, otherwise the frequency will change. When more renewable power is integrated in the system there will be more problems with the frequency. So the renewable power systems are in need of a way to control the power generation in order to reduce the weather dependency. The renewable could be installed with complementary energy storage. The way of controlling the power generation for the traditional sources is by feeding in more fuel. So in some sense the fuel for nuclear, fossil and hydropower are a type of energy storage. Energy can be stored in different forms such as latent and sensible heat, kinetic energy, chemical energy and in an electrical field [2]. Well known portable solutions for energy storage is electrical vehicle or in small electronics.
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