• Energy Research

As solar photovoltaic and wind based power generation becomes more commonplace, the inherent intermittency of the solar and wind resource poses one of the great challenges to those who would design and implement the next generation smart grid. Speci cally, grid tied solar power generation is a distributed resource whose output can change extremely rapidly, resulting in many issues for the distribution system operator with a large quantity of installed photovoltaic devices. Battery energy storage systems are increasingly being used to help integrate solar and wind power into the grid. These systems are capable of absorbing and delivering both real and reactive power with sub second response times. With these capabilities, battery energy storage systems can mitigate such issues with solar wind power generation as ramp rate, frequency, and voltage issues. Beyond these applications focusing on system stability, energy storage control systems can also be integrated with energy markets to make the solar and wind resource more economical. Providing a high level introduction to this application area, this paper presents an overview of the challenges of integrating solar and wind power to the electricity distribution system.In this paper a solar wind based power system model is made. To smoothen the intermittency of the solar and wind resources a battery energy storage system BESS is employed. The battery energy storage system stores the energy when excess power is available and releases the stored energy when demand is higher than the supply. A PI controller based control scheme is implemented for this purpose and an MPPT is used for wind turbine to extract the maximum power from the wind resource.The validity of the control scheme is checked through the MATLAB simulation of the solar wind based power system. Rajesh Kumar | Satish Kumar "Power Quality Improvement in Solar-Wind based Power System using BESS" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-4 , June 2017, URL: https://www.ijtsrd.com/papers/ijtsrd164.pdf

Abstract Underdeveloped, remote and outermost (3T) regions are areas that are becoming the priority of development by the Government of the Indonesian Republic in strengthening national security. However, the constraints to development in the 3T region are immense, ranging from great distances, isolated areas to its geographical location in the mountainous area of even in small islands. Pasi Island is home to three villages that fall into the 3T area category. Battery ESS is an energy storage system in the form of giant batteries with many advantages, such as inexpensive, mobile, has a large capacity, long life cycle, easy to operate and zero waste. Seeing the advantages offered by the battery ESS so that it has the potential to be an optimal solution to meet the electrification ratio in the 3T region. Cost-benefit analysis is chosen because the results can provide a clearer picture of the costs and benefits going forward. So that the calculation of the resulting cost-benefit is more optimal then two calculation scenarios are used using the basic difference in electricity sales rates. In the first scenario, it uses BPP tariff for the Selayar Regency area of Rp 2,445, and in the second scenario, it uses the BPP tariff of Rp 3,041 for small subsystem areas. The calculation results indicated that the second scenario provided immense benefits with a short payback time. The NPV value generated by scenario II is 116.5 billion rupiah with an IRR percentage of 100.33% and a cost-benefit ratio of 9.332.

Περίληψη: Οι προσπάθειες για την μείωση της χρήσης των πηγών ορυκτών καυσίμων και την αντικατάσταση τους από Ανανεώσιμες Πηγές Ενέργειας (ΑΠΕ) συγκεντρώνονται στην μείωση των εκπομπών από την παραγωγή, μεταφορά και κατανάλωση ενέργειας. Τα τελευταία χρόνια έχουν χαραχθεί πολιτικές που αφορούν τη δημιουργία θεσμικού και χρηματοοικονομικού πλαισίου για την στήριξη της ένταξης των ΑΠΕ στους τομείς της ηλεκτροπαραγωγής, της θέρμανσης και των μεταφορών. Η Ελλάδα διαθέτει πλούσιο δυναμικό σε ΑΠΕ. Η αιολική ενέργεια πρωταγωνιστεί στην ανάπτυξη των ΑΠΕ και παρουσιάζει σημαντικές επενδυτικές δυνατότητες στην Ελλάδα. Η Ελλάδα παρουσιάζει επίσης ένα ιδιαίτερα υψηλό ηλιακό δυναμικό, περίπου 1.400-1.800 (kWh/(m2.yr)) ετησίως σε οριζόντιο επίπεδο, ανάλογα το γεωγραφικό πλάτος και το ανάγλυφο της περιοχής. Στην παρούσα εργασία θα παρουσιαστούν αναλυτικά οι τεχνολογίες των συστημάτων ΑΠΕ και συγκεκριμένα, των Φωτοβολταϊκών τεχνολογιών, των υδροηλεκτρικών έργων και των συστημάτων αποθήκευσης ενέργειας, με στόχο να διερευνηθεί η δυνατότητα ηλεκτροδότησης φορτίων μέσω φωτοβολταϊκών και υδροηλεκτρικών σταθμών με σύστημα αποθήκευσης μπαταριών, όπου υλοποιείται έλεγχος συχνότητας. Summarization: Efforts to reduce the use of fossil fuel sources and replace them with Renewable Energy Sources (RES) combine emission reductions from energy production, transport and consumption. In recent years, policies have been devised to create an institutional and financial framework to support the integration of RES in the fields of power generation, heating and transport. Greece has a rich potential in RES. Wind energy is a leading factor in the development of RES and presents significant investment opportunities in Greece. Greece also has a particularly high potential of solar capacity of approximately 1,400-1,800 (kWh / (m2.yr)) per year on a horizontal level depending on the latitude of the area. In this thesis, the technologies of RES systems, especially Photovoltaic technologies, hydroelectric projects and energy storage systems, will be presented in order to investigate the possibility of electrification of loads through photovoltaic and hydroelectric stations with a storage battery system where frequency control is performed.

Die vorliegende Arbeit untersucht den Anwendungsfall eines Batteriespeichersystems im multimodalen Betrieb. Die Systemdienstleistungen zur Vorhaltung bzw. Bereitstellung von Prim��rregelleistung zur Frequenzhaltung im Verbundnetz und die gleichzeitige Erbringung von Blindleistung f��r die statische Spannungshaltung sind Aufgabe des Batteriespeichersystems. Die Kriterien f��r speicherbegrenzte technische Einheiten zur Teilnahme an den Regelenergie-Ausschreibungen sind eindeutig definiert. Ein wirtschaftlicher Betrieb von Batteriespeichern zur Erbringung von Prim��rregelleistung ist aufgrund der hohen Investitionskosten herausfordernd. Durch den in Zukunft verst��rkten Ausbau von Batteriespeichersystemen wird es noch schwieriger, Ertr��ge mit der Erbringung von Prim��rregelleistung zu erzielen. Daher ist ein multimodaler Betrieb des Speichers ein f��r das Energienetz vorteilhaftes Konzept. Zugleich ist es auch ein wirtschaftlich n��tzliches Verhalten. Im Folgenden wird der Batteriespeicher zur Vorhaltung bzw. Bereitstellung von Prim��rregelleistung analysiert. Das erforderliche Lademanagement gem���� den Kriterien f��r speicherbegrenzte Einheiten wird im System implementiert. Der Einfluss verschiedener Speicherverh��ltnisse, die Aktivierung von Freiheitsgraden zur Unterst��tzung des Lademanagements und die Variation des Sollzustandes des Batterieladestatus im Hinblick auf den Energieaufwand des Lademanagements wird untersucht. Zus��tzlich wird der multimodale Betrieb zur Vorhaltung bzw. Bereitstellung von Prim��rregelleistung und die Erbringung von Blindleistung ��berpr��ft. Eine Logik zur Beschr��nkung der Leistungen im Falle einer ��berschreitung der maximalen Scheinleistung des Umrichters wird im System integriert. Die Ergebnisse zeigen, dass ein multimodaler Betrieb eines Batteriespeichersystems grunds��tzlich m��glich ist. Der Einsatz von Freiheitsgraden und Kombination daraus senkt den Energieaufwand des Lademanagements. Die Variation des Sollzustandes des Batterieladestatus k��nnen in Abh��ngigkeit von den Frequenzdaten ebenfalls den Energieaufwand des Lademanagements reduzieren. Durch den produktiven Einsatz dieser frei w��hlbaren Variablen k��nnen Kosten eingespart werden. ��berdies ist beobachtbar, dass bei der Dimensionierung des Batteriespeichers ein niedrigeres Speicherverh��ltnis sinnvoll ist. Das bedeutet eine kleine nutzbare Speicherkapazit��t in Relation zu einer gro��en pr��qualifizierten Prim��rregelleistung. Mit den gegebenen Eingangsdaten kann zus��tzlich zur Prim��rregelleistung gleichzeitig die Blindleistung ohne Einschr��nkungen bereitgestellt werden. The present diploma thesis studies the application of a battery storage system in a multimodal operation. European transmission system services such as frequency containment reserve for the stabilization of the grid frequency and the provision of reactive power due to static change of voltage are implemented in the battery storage system. Both services are executed simultaneously. Units with limited capacity have to comply with certain clearly defined criteria to participate on the market for regulation services. Due to high investment costs for battery storage systems an economic operation only for frequency containment reserve is challenging. The increasing expansion of battery storage systems will make it even more difficult to create revenues in the future. Therefore, a multimodal operation is an economically useful concept. It also has many advantages for the power transmission grid. The operation of a battery storage system for frequency containment reserve will be analysed below. A SoC-Management which is to fulfill the criteria is integrated in the system. The influence of different storage ratio, the variance of supporting the SoC-Management and the variation of target SoC on the energy expenditure of the SoC-Managent are examined. In addition, the multimodal operation for frequency containment reserve and the provision of reactive power are studied. In case of exceeding the maximum apparent power of the inverter the active or reactive power is reduced. A multimodal operation with a battery storage system is in principle possible as shown in the results of the simulations. The activation of variance and combinations therefore reduce the energy expenditure of the SoC-Management. The variation of target SoC can reduce the energy effort of the SoC-Management depending on the frequency data used. Energy and by that costs can be reduced through the productive use of these freely selectable variables. The investigation shows, that a smaller storage ratio for the battery storage system is reasonable; that means a small usable storage capacity in relation to a large power. Frequency containment reserve and at the same time the provision of reactive power can be provided without restrictions from the battery storage system.

Development of Battery Energy Storage System projects and their subsequent installation and connection to electrical grids throughout the world is expected to increase over the coming years. Two key concerns are at the forefront of entities undertaking these installations. The first is determining the optimal BESS size for a given application. The second is whether this optimal BESS size reflects the goals (referred to as planning objectives in this dissertation) set out in the BESS project planning phase. Recognising these two concerns, it is determined that BESS sizing approaches must be fit for purpose, can be used adequality as a planning tool and capable of modelling important planning objectives. The Front-End Planning framework was utilised in this dissertation as a means to assess if existing BESS sizing approaches are suitable for modelling planning objectives as part of BESS project planning. In total, 32 of the most-cited articles from the BESS sizing literature were reviewed for their inclusiveness of scoping elements set out by the Front-End Planning framework. The results of this review showed that existing BESS sizing approaches are lacking in three key planning objectives called Investment Scale, Investment Timing and Dispatch Adaptability. This research sought to answer the following questions: 1) Is it possible to form the planning objectives Investment Scale, Investment Timing and Dispatch Adaptability as part of optimising energy capacity size for new BESS installations seeking maximum profit? 2) Are there any circumstances where the inclusion of the three planning objectives as part of BESS sizing helps overcome shortcomings of existing sizing approaches? To incorporate the planning objective Investment Scale as part of BESS sizing, maximisation of opposing financial objective functions using two different multi-objective optimisation methods called Rating Method and Paired Comparison was used. These approaches were tested on a simple microgrid under various electricity price scenarios. The results show that the Rating Method performed best when selecting BESS size in significant knee regions near maximum daily worth. The Rating Method can also select optimal BESS size at maximum daily worth when less-significant knee regions are present. This approach gives an appropriate balance between forming the planning objective Investment Scale and maximising profit. To incorporate the planning objective Investment Timing as part of BESS sizing, two different models were used, referred to as the operational model (controlling operational decisions i.e. BESS dispatch) and the planning model (controlling BESS size at different yearly intervals). Reinforcement learning was used as the operational model solution method, while global optimisation was used as the solution method for planning model. This approach was tested on data from the Integrated Single Electricity Market Day-Ahead Market. It was found that splitting BESS operational decisions and BESS planning decisions into two different models is an effective technique. To incorporate the planning objective Dispatch Adaptability as part of BESS sizing, model-based and model-free stochastic optimisation methods are used. This was done for model-free optimisation by utilising deep reinforcement learning methods, while stochastic programming was used as the solution method for model-based approach. Both approaches were tested on historical Day-Ahead and Intraday Markets electricity clearing prices from the Integrated Single Electricity Market. It was found that the model-based approach outperformed the model-free approach. However, it is not clear that such a broad statement can be made about model-free and model-based approaches in general based on the results gained through this thesis. The significance of this study’s results is that BESS sizing is now more functional and adaptable for project planning purposes. It is now possible to size BESS without suffering scale issues resulting from ever-diminishing returns of larger BESS sizes, where the timing of the investment can be chosen optimally rather than assuming “here and now” investment, and where the operational strategy employed to simulate BESS dispatch is more reflective of actual BESS use and adaptability.

Renewable energy has been playing an increasingly important role worldwide recently. For 2012 and 2013, renewables contributed 19% to energy consumption and 22% to electricity generation. In 2014, solar energy represented 36% of new generating capacity in the U.S., second only to natural gas. Due to the intermittent nature of renewable sources, energy storage systems have been integrated into the architecture of Microgrid systems to make them more efficient and robust. Within a Microgrid system, the battery energy storage system (BESS) can be used to reduce the electricity cost by delivering energy during the On-Peak rate period and storing energy (i.e. charging) during the Off-Peak rate period. This thesis proposes a real-time battery control method to reduce the electrical bill in an energy intensive environment, and more effectively utilize a BESS within Microgrid testbed system at the College of Engineering Center for Environmental Research and Technology (CE-CERT). The monthly electrical bill is based on the rate schedule time-of-use (TOU) for Large General and Industrial Service in the city of Riverside. Each month, this rate schedule has both demand charge (kW) and energy consumption (kWh) charge for three different rate periods: On-Peak, Mid-Peak, and Off-Peak. The real-time control method considers both rates for different rate periods separately. The main parts of the control method are the control algorithms, which comprise two model predictive control (MPC) algorithms, for the On-Peak rate period. The first algorithm is called the constant threshold MPC (CT-MPC) algorithm, and it is implemented in the system with the relatively stable solar generation and building load profiles in the winter season. This control algorithm can maintain the On-Peak demand below the constant threshold during the entire On-Peak rate period. The second one is called the adjusting demand threshold MPC (ADT-MPC) algorithm. The ADT-MPC algorithm fits a system with unpredictable solar generation and building load profiles. During the On-Peak rate period, by applying the ADT-MPC algorithm, the On-Peak threshold can be adjusted to optimized values. Both algorithms can maintain a low level of energy import from the external grid (i.e. Riverside Public Utilities grid) during the On-Peak rate period. For the other two rate periods, the Off-Peak and Mid-Peak control algorithms are also developed. With the real-time battery control method, the BESS continuously maintains the lowest demand and energy consumption for the entire day.

It has become imperative for the power and energy engineers to look out for the renewable energy sources such as sun, wind, geothermal, ocean and biomass as sustainable, cost effective and environment friendly alternatives for conventional energy sources. However, the non availability of these renewable energy resources all the time throughout the year has led to research in the area of hybrid renewable energy systems. In the past few years, a lot of research has taken place in the design, optimization, operation and control of the renewable hybrid energy systems. It is indeed evident that this area is still emerging and vast in scope. The main aim of this paper is to review the research on the unit sizing, optimization, energy management and modeling of the hybrid renewable energy system components. Developments in research on modeling of hybrid energy resources PV systems , backup energy systems Fuel Cell, Battery, Ultra capacitor, Diesel Generator , power conditioning units MPPT converters, Buck Boost converters, Battery chargers and techniques for energy flow management have been discussed in detail. In this paper, an attempt has been made to present a comprehensive review of the research in this area in the past one decade. Dipti "A Review on Unit Sizing, Optimization and Energy Management of HRES" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-5 , August 2018, URL: https://www.ijtsrd.com/papers/ijtsrd15840.pdf