Taajuusohjatun reservin käyttöönotto Suomessa

Frequency controlled Frequency Containment Reserves (FCR) regulate automatically according to changes in the Nordic power system's system frequency. As the frequency declines from its nominal value, up-regulation commences by increasing the reserve providing unit's electricity production or by decreasing its electricity consumption. Additionally, the Frequency Containment Reserve in Normal operation (FCR-N) down-regulates by increasing the unit's consumption or by decreasing its production when the system frequency rises above the nominal value. In Finland, hydropower has traditionally acted as the main source of FCR capacity. However, active power capacity from other resources may also be offered to the FCR market places. For example, even modest Demand Response (DR) capacity is sufficient for market utilization if it is incorporated into an aggregation of reserve power capacity, as long as the entire aggregated ensemble fulfills the market place's rules. Another modern resource especially suitable for FCR-N utilization are the Battery Energy Storage Systems (BESS). The energy capacity stored in the batteries is limited, however, and exhausted in continuous activation. In this Master's thesis, the technical requirements currently applied to th Frequency Containment Reserves were examined. Based on the requirements, the necessary commissioning process including four regulating tests were formulated and pre-approved by the Finnish Transmission System Operator Fingrid Oyj. The regulating tests are universally applicable, thus allowing the verification of compliance to the requirements for both conventional and modern resources. Furthermore, the expected future evolution of the technical requirements was studied by interviewing Fingrid's specialist. The suitability of the formulated tests was assessed by performing regulating tests on a BESS. The acquired results indicated that the BESS fulfills the regulating requirements of both FCR market places. Additionally, the regulating tests formulated in this thesis were verified as suitable for performing the official regulating tests.Taajuusohjatut käyttö- ja häiriöreservit reagoivat automaattisesti pohjoismaisen sähköjärjestelmän taajuuden vaihteluihin. Taajuuden laskiessa nimellisestä ne lisäävät tuotantoaan tai vähentävät kulutustaan, mitä kutsutaan ylössäädöksi. Lisäksi taajuusohjattu käyttöreservi alassäätää taajuuden noustessa nimellisestä vähentämällä tuotantoa tai lisäämällä kulutusta. Ylös- ja alassäädöllä pyritään siis tasaamaan sähkön kulutuksen ja tuotannon välistä eroa. Vesivoima on perinteisesti toiminut Suomessa taajuusohjattujen käyttö- ja häiriöreservien lähteenä. Kuitenkin myös muu pätötehokapasiteetti soveltuu taajuus-ohjattujen reservien markkinapaikoille. Esimerkiksi pienimuotoinenkin sähkönkulutuksen kysyntäjousto voidaan hyödyntää, kun se liitetään osaksi suurempaa, aggregoitua kokonaisuutta. Aggregoimalla voidaan siis pienistä teholähteistä koostaa markkinavaatimukset täyttävä kokonaisuus. Toinen moderni, erityisesti käyttöreservikapasiteetiksi soveltuva tehonlähde ovat akkukäyttöiset sähkövarastot. Näiden erikoispiirre on akustojen jatkuvassa käytössä ehtyvä energiakapasiteetti, minkä vuoksi sähkövarastoille tulee antaa reservikäytössä palautumisaikaa. Tässä diplomityössä tutustuttiin nykyisiin taajuusohjatuille käyttö- ja häiriöreserveille asetettuihin teknisiin vaatimuksiin. Nykyvaatimusten pohjalta muotoiltiin tarvittava käyttöönottoprosessi, mukaan lukien neljä yleisesti sovellettavissa olevaa säätökoekäyrää, joiden avulla niin perinteisten kuin uudempienkin taajuusohjattujen reservien ylläpitoon aiottujen yksiköiden soveltuvuus voidaan todentaa. Säätökoekäyrät hyväksytettiin Suomen kantaverkkoyhtiö Fingrid Oyj:llä. Lisäksi diplomityössä tutustuttiin vaatimuksiin tulevaisuudessa tehtäviin muutoksiin haastattelemalla Fingridin asiantuntijaa. Laadittuja säätökoekäyriä testattiin hyödyntämällä niitä akkukäyttöisen sähkövaraston vaatimustenmukaisten säätöominaisuuksien todentamisessa. Säätökokeista saatujen tulosten perusteella sähkövarasto täytti sekä käyttö- että häiriöreserveille asetetut säätövaatimukset. Samalla todennettiin säätökoekäyrien soveltuvuus virallisten säätökokeiden suorittamiseen

The Impact of Large-Scale Renewable Energy on Grid Small-Signal and Frequency Stability: Modelling, Analysis, and Control

This thesis intends to discuss the influence of renewable energy sources (RES) on the stability of power system. Although integration of renewable brings incalculable optimistic aspects, the variability of RES concerning fluctuation of active power may exhibit adverse influence on stability issues regarding small-signal and frequency stability point of views. Thus, this thesis discusses those two stability aspects. From small-signal stability perspectives, the agenda is divided into three parts. First small signal research investigates the influence of time-varying RES on low frequency oscillation, which triggers weak frequency band of vulnerable modes on remote area. Second study of small signal is to observe the influence of high penetration change on interarea oscillation. Third research of small signal is to investigate the influence of solar irradiation and wind velocity with stochastic characteristics on small signal stability due to the change of the generation quantity of photovoltaics (PV) and wind turbine generators (WTG). From frequency stability perspectives, the future grid might be operated under reduced inertia and high penetration, resulting in deterioration of frequency stability. Against this backdrop, ESS emerges as a countermeasure for the implications of large fleet of RES. First chapter of frequency stability aspects introduces ESS methodology enabling ESS to coordinate ancillary service among existing equipment with proposed method: droop control and State-of-Charge feedback (DaSOF). The last chapter suggests a method for EV application, based on Smart Charging method and DaSOF method. The efficacy of large group of EV application with this method against variability of RES is investigated and proved on the Jeju island system in Korea

Operational concepts for grid services using electric vehicles

The European electricity grid is subject to increasing stresses due to increasing share of volatile renewable energy technologies. These technologies, coupled with higher volatility in demand, pose challenges to the stability and security of the European grid, erstwhile dominated by large and relatively reliable conventional generation. As the contribution of wind and photovoltaic generation increases in the energy mix, it demands an assessment of the corresponding risk to frequency stability and possible preventive measures. Uncontrolled charging of the increasing number of electric vehicles in Germany also demands a thorough investigation of methods for their integration in the electricity grid to not only improve grid frequency stability but also to provide secondary benefits to electric vehicle users. This work analyzes the load frequency control systems for their suitability for integration of electric vehicles and the impact of increase in volatile renewable energy on frequency stability for the case of Germany, showing a significant increase in reserve requirements. Evaluation of alternative approaches to load frequency control on the basis of infrastructure requirements shows that introduction of an aggregator of distributed energy resources can significantly reduce the overall infrastructure requirements for grid operators. The operational concepts herein proposed are evaluated using several case studies for optimizing the use of electric vehicles for grid flexibility services by taking into account the usage requirements of the vehicle owner and supply requirements of grid services.Das europäische Stromnetz ist aufgrund des steigenden Anteils volatiler erneuerbare Energiequellen einer zunehmenden Belastung ausgesetzt. Diese Technologien, in Ver-bindung mit einer höheren Volatilität der Nachfrage, stellen eine Herausforderung für die Stabilität und Sicherheit des europäischen Netzes dar, das früher von einer zentrali-sierteren Erzeugung in großen und relativ zuverlässigen konventionellen Kraftwerken geprägt war. Mit zunehmendem Beitrag der Wind- und Photovoltaikerzeugung am Energiemix ist eine Bewertung des Risikos für die Frequenzstabilität und mögliche Prä-ventivmaßnahmen erforderlich. Die ungesteuerte Aufladung der zunehmenden Anzahl von Elektrofahrzeugen in Deutschland erfordert auch eine gründliche Untersuchung der Methoden für ihre Integration in das Stromnetz, um nicht nur die Stabilität der Strom-netzfrequenz zu verbessern, sondern auch einen sekundären Nutzen für die Elektrofahr-zeug-Nutzer zu erzielen. Diese Arbeit analysiert die Lastfrequenzregelungssysteme auf ihre Eignung zur Integration von Elektrofahrzeugen ins Stromnetz sowie die Auswir-kungen der Erhöhung des Anteils von volatilen erneuerbaren Energien auf die Frequenz-stabilität in Deutschland, und zeigt einen deutlichen Anstieg der Anforderungen an Re-servekapazität. Die Bewertung alternativer Ansätze zur Lastfrequenzsteuerung auf der Grundlage von Infrastrukturanforderungen zeigt, dass die Einführung eines verteilten Energieressourcen Aggregators den gesamten Infrastrukturbedarf der Netzbetreiber deutlich reduzieren kann. Die hierin vorgeschlagenen Betriebskonzepte werden anhand mehrerer Fallstudien zur Optimierung des Einsatzes von Elektrofahrzeugen für Flexibili-tätsdienstleistungen im Stromnetz unter Berücksichtigung der Anforderungen der Fahr-zeughalter und des Versorgungsbedarfs von Netzdiensten bewertetThis thesis deals with the challenges to frequency stability in the European electricity grid posed by the increasing share of renewable energy resources and electric vehicles. It evaluates European load frequency control systems for their suitability for integration of electric vehicles and the impact of increase in photovoltaic and wind power on frequency stability for the case of Germany, demonstrating a consequent significant increase in frequency control reserve requirements. Evaluation of alternative approaches to load frequency control shows that introduction of an aggregator of distributed energy resources can also significantly reduce the overall infrastructure requirements for grid operators. The operational concepts herein proposed are evaluated using several case studies for optimizing the use of electric vehicles for grid flexibility services by taking into account the user behavior of vehicle owners and supply requirements of these grid services

Enabling Electric Aircraft_Applications and Approaches

Climate concerns have instigated serious research for weight-critical batteries to enable what are termed EVs, electric vehicles, initially for ground transportation. This research has advanced to the point where, at the system level, parity with combustion engines, via vehicle weight and drag reductions to reduce battery requirements, along with continued battery research, can conceivably be achieved in less than 10 years.. Concomitantly, renewable electric generation, which would enable essentially emission-less transportation, has via cost reductions, efficiency improvements and storage research advanced to the point of producing 25% of current electrical generation and 62% of new generation capability with continued rapid cost reductions and consequent rapid further adoption projected. The present report examines the resultant electric aircraft possibilities and opportunities including technologies to reduce requisite battery size and weight via airframe performance improvements, the benefits of electric propulsion and the enablement of a massive new aeronautics market for affordable, safe personal air vehicles that operate off of local streets

An assessment of inductive coupling roadway powered vehicles

The technical concept underlying the roadway powered vehicle system is the combination of an electrical power source embedded in the roadway and a vehicle-mounted power pickup that is inductively coupled to the roadway power source. The feasibility of such a system, implemented on a large scale was investigated. Factors considered included current and potential transportation modes and requirements, economics, energy, technology, social and institutional issues. These factors interrelate in highly complex ways, and a firm understanding of each of them does not yet exist. The study therefore was structured to manipulate known data in equally complex ways to produce a schema of options and useful questions that can form a basis for further, harder research. A dialectical inquiry technique was used in which two adversary teams, mediated by a third-party team, debated each factor and its interrelationship with the whole of the known information on the topic

Converter based electrochemical impedance spectroscopy for fuel cell stacks

Fuel cells are important devices in a hydrogen-based chain of energy conversion. They have distinctive advantages over batteries with their higher energy density and faster refueling speed, which make them attractive in stationary power supplies and heavy-duty vehicles. However, the high cost and low durability associated with modern fuel cells are still hindering their wider commercialization. Besides developing more reliable and lower cost materials and advanced assemblies of cells and stacks, a practical and effective diagnostic tool is highly needed for fuel cells to identify any abnormal internal conditions and assist with maintenance scheduling or application of on-board mitigating schemes. Conventionally, linear instruments were used for fuel cell EIS, however, limited to single cells or short stacks only as a laboratory testing method. With recent developments, EIS enabled by switching power converters are capable of being applied to a high-power stack directly. This approach has the potential for practical field applications such as a servicing tool for fuel cell manufacturers or an on-board diagnostic tool of a moving vehicle. Previous works on converter based EIS have made a few different attempts at conceptually realizing this solution while several significant issues were not well recognized and resolved yet. As such, this thesis explores further on this topic to address the flexibility of EIS perturbation generation, the perturbation frequency range, and the linkage between fuel cell EIS requirements and the converter design to push for its readiness for practical implementations. Several new solutions are proposed and discussed in detail, including a total software approach for existing high-power converters to enable wide-frequency-range EIS, a redesign of the main dc/dc converter enabling wide-frequency-range perturbations, and a separate auxiliary converter as a standalone module for EIS operation. A detailed analysis of oscillations brought by converter based EIS in powertrains is also presented

The Enabling Technologies for a Quasi-Zero Emissions Commuter Aircraft

The desire for greener aircraft pushes both academic and industrial research into developing technologies, manufacturing, and operational strategies providing emissions abatement. At time of writing, there are no certified electric aircraft for passengers’ transport. This is due to the requirements of lightness, reliability, safety, comfort, and operational capability of the fast air transport, which are not completely met by the state-of-the-art technology. Recent studies have shown that new aero-propulsive technologies do not provide significant fuel burn reduction, unless the operational ranges are limited to short regional routes or the electric storage capability is unrealistically high, and that this little advantage comes at increased gross weight and operational costs. Therefore, a significant impact into aviation emissions reduction can only be obtained with a revolutionary design, which integrates disruptive technologies starting from the preliminary design phase. This paper reviews the recent advances in propulsions, aerodynamics, and structures to present the enabling technologies for a low emissions aircraft, with a focus on the commuter category. In fact, it is the opinion of the European Community, which has financed several projects, that advances on the small air transport will be a fundamental step to assess the results and pave the way for large greener airplanes