変動性再生可能エネルギー大量導入に伴う統合費用の評価方法に関する検討

One of the main goal of energy transition is the decarbonization of global electricity networks. Toward this aim, the integration of Variable Renewable Energy Sources with the electricity grid has increased dramatically over the last ten years. However, the desire to obtain large fractions of electricity from VER has encountered many challenges mainly due to their random nature. The Vanadium Redox Flow Battery represents one of the most promising technologies for large stationary applications of electricity storage. It has an independent power and energy scalability, together with long life cycle and low long-term self-discharge process, which make it useful in applications where batteries need to remain charged for long periods of time while maintaining a state of readiness for use. The usage of such battery, coupled with variable renewable energy sources, allows to overcome the constraints linked to the limited dispatchability of the latter, thus favoring a large penetration of variable renewable energy source in the power grid. This article proposes to study the energy storage through Vanadium Redox Flow Batteries as a storage system that can supply firm capacity and be remunerated by means of a Capacity Remuneration Mechanism. We discuss a real option model to evaluate the value of investment in such technology. KeywordsEnergy storage systemsRenewable energyElectrical gridVanadium redox flow batteriesReal optionsCapacity markets

This paper presents a control design methodology that addresses high penetration of variable generation or renewable energy sources and loads for networked AC /DC microgrid systems as an islanded subsystem or as part of larger electric power grid systems. High performance microgrid systems that contain large amounts of stochastic sources and loads is a major goal for the future of electric power systems. Alternatively, methods for controlling and analyzing AC/ DC microgrid systems will provide an understanding into the tradeoffs that can be made during the design phase. This method develops both a control design methodology and realizable hierarchical controllers that are based on the Hamiltonian Surface Shaping and Power Flow Control (HSSPFC) methodology that regulates renewable energy sources, varying loads and identifies energy storage requirements for a networked AC/DC microgrid system. Both static and dynamic stability conditions are derived. A renewable energy scenario is considered for a networked three DC microgrids tied into an AC ringbus configuration. Numerical simulation results are presented.

Coordinated operation schedule of microgrids in consideration of penetration of variable renewable energy sources

The high penetration of inverter-fed renewable energy sources (RESs) in modern energy systems has led to a reduction in the system’s inertial response. This reduction in the rotational inertial response is associated with synchronous generation and might result in a deteriorated frequency response following a power disturbance. This paper investigates the frequency stability of the Kingdom of Saudi Arabia’s (KSA) grid. It includes a description of the changing energy landscape of the KSA’s electricity grid and an investigation of the impact of high penetration levels of inverter-fed RESs on the dynamic behavior of the KSA grid. The impact of RESs has been studied through a simulation of case studies of the future KSA power system using the MATLAB/Simulink simulation software. The frequency stability of the KSA’s power system has been evaluated with various RES levels under peak and base load conditions. The simulation results show that the high penetration levels of RESs dramatically affect the system’s frequency response, especially under off-peak conditions. In addition, the significance of battery energy storage systems (BESSs) for compensating the reduction in the system inertial response has been addressed. The results show the effectiveness of aggregated BESSs for enhancing the system frequency control of the KSA grid.

With the emergence of favorable policies and effective financing schemes to allow for large penetrations of variable renewable energy resources tied into the electricity grid, there are increasing RD in turn, as variable renewable energy (VRE) resource penetrations increase, their impact on grid reliability, stability, and energy quality also increase. A key challenge for utility and system operators is the ability to forecast this variability over time periods of a few minutes to several days in the future. R&D programs on weather-driven energy resource variability and the ability to forecast this variability have been undertaken in the U.S. and elsewhere. These programs include special field measurement campaigns, data processing techniques, and modeling schemes devised to quantify and forecast the characteristics of this variability in the electricity grid. After introducing the challenge of high penetrations of VRE in a transmission or distribution system, this chapter highlights some key studies underway or completed, with special emphasis on characterizing and predicting solar system output variability associated with rapid cloud passages or changing weather patterns. Some of these studies have been undertaken as a significant international collaboration established under the International Energy Agency’s (IEA’s) Solar Heating and Cooling (SHC) Implementing Agreement’s Task 36 “Solar Resource Knowledge Management,” and a new Task 46 currently underway titled “Solar Resource Assessment and Forecasting.”

The operation of electric and heat grids alike is complicated due to the dynamic demand, with the increasing penetration of renewable energy sources adding to the problem. In order to improve the integration of variable renewable energy sources, the flexibility of the system needs to be improved. This paper proposed a novel characterization of the short-term energy flexibility, which was further utilized for the district heating capacity extension. The soft-linking of the models includes feedback, but the added computational complexity is kept at a minimum. Compared to the other literature in the field, due to the accurate characterization of the dynamics of the energy flexibility, flexibility is utilized much more frequently. The method was demonstrated for the case of the district heating of Zagreb. Results showed that both capital and operational savings can be achieved by adopting the proposed method. In the best performing scenario, which included the capacity extension planning, the savings of the district heating system were 5.4%. The extensive power exchange in the best performing scenario meant that the flexibility was used to help balancing the power grid as well.

Optimal sizing and placement of battery energy storage system for maximum variable renewable energy penetration considering demand response flexibility: A case in Lombok power system, Indonesia

Chapter 9 - Integrated Planning of Energy and Water Supply in Islands

The effect of short term storage operation on resource adequacy

The increasing penetration of variable and unpredictable renewable energy sources into the liberalized electricity market brings about significant changes in the management strategies of fossil fuel power plants. These new operation modes cause remarkable effects on the lifetime of the plants. Consequently, the operators of the plants need to be assisted by effective procedures, which are able to define suitable production plans. In the present paper, the authors propose a dynamic model which can be used to estimate the effects of the variations of thermodynamic and mechanical parameters during transient operation, start-ups and shut-downs. To check the effectiveness of the model, a combined cycle plant with a three-pressure level heat recovery steam generator has been selected. The geometry of the components, the influence of the environmental conditions, and the control strategies are included in the model. In this way, the residual lifetime of the most critical components can be predicted.

Estimating the additional operating reserve in power systems with installed renewable energy sources

Pumped hydroelectric storage (PHS) is the main utility-scale storage technology. Although PHS systems generally constitute a fraction of generation, they receive increasing attention due to their potential balancing role towards higher penetration of variable renewable energy sources (RES). In the European context it is widely believed that PHS are key elements of the ongoing energy transition. The present analysis examines if this assumption is valid and PHS utilization grows parallel to RES. We collected, harmonised and analysed datasets for 1991–2016 revealing an uneven utilization among European states. While certain countries increased the utilization rates of PHS by a factor of three to four, in several others PHS units are heavily under-utilized. In three extreme cases the utilization rate, compared to the past, is at 10–25% level. We analysed this controversy by identifying tendencies in the electricity markets, ownership and management status in the various countries, as well as competition with other technologies with balancing potential. Finally, we developed a new approach to display PHS tendencies in a compact picture. Building on the growth-share matrix Economics framework, we identified the strategic direction of PHS for each of the analysed countries.

Sustainable transition pathways with high penetration of variable renewable energy in the coal-based energy systems

Introduction: To date, a variety of studies have been published on the topic of long term energy system transition. Most studies on future energy systems, however, have a shorter time frame or adopt a supranational focus (e.g. the Energy Roadmap, 2011 or the World Energy Outlook, 2015). It then constitutes a sincere challenge to perform a national energy system transition study with as time horizon 2050 and covering a far-reaching transformation of the energy system. VITO, together with the FPB (Federal Planning Bureau) and ICEDD, performed a study to scrutinise the transition of the Belgian national energy system towards a future mix entirely based on renewable energy sources. The focus on renewable energy sources and on building a national energy system completely running on renewable energy can be traced back to three main concerns: – Climate change: Renewable energy sources (RES) are a major instrument in the fight against climate change as RES do not release (net) greenhouse gas emissions. – Security...

Energy storage units offer vital balancing power for energy systems with an increasing amount of variable renewable energy (VRE) sources. The operation of such systems can be optimized by stochastic programming, which anticipates the uncertainty related to the variable renewable energy sources. However, these optimization problems can only be formulated for optimization horizons with a finite length, due to the rapidly increasing problem size and uncertainty in VRE production. Realistic valuation of the stored energy at the end of a horizon is important for long-term operation of the system. In this work, we investigate two different valuation methods, which are based on forecasted electricity prices, for storage-only and producer-oriented energy systems that participate in the day-ahead market. On a case study on the German day-ahead market, the methods yield competitive profits with reduced cycling of the energy storage unit and deviations with respect to the day-ahead trading.