scholarly journals Impact of Revised Time of Use Tariff on Variable Renewable Energy Curtailment on Jeju Island

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 135
Author(s):  
Jinyeong Lee ◽  
Jaehee Lee ◽  
Young-Min Wi

Jeju Island announced the “Carbon Free Island (CFI) Plan by 2030” in 2012. This plan aims to replace conventional generators with distributed energy resources (DERs) up to a level of 70% by 2030. Akin to Jeju Island, as DERs have been expanded in islanded power systems, variable renewable energy (VRE) has become a significant component of DERs. However, VRE curtailment can occur to meet power balance, and VRE curtailment generally causes energy waste and low efficiency, so it should be minimized. This paper first presents a systematic procedure for estimating the annual VRE curtailment for the stable operation of the islanded power systems. In this procedure, the VRE curtailment is estimated based on the power demand, the grid interconnection, the capacity factor of VRE, and conventional generators in the base year. Next, through the analysis of the hourly net load profile for the year in which the VRE curtailment is expected to occur, a procedure was proposed to find the season and hour when VRE curtailment occurs the most. It could be applied to revised Time-of-Use (ToU) tariff rates as the most cost-effective mitigation method of VRE curtailment on the retail market-side. Finally, price elasticity of electricity demand was presented for applying the revised ToU tariff rate scenarios in a specific season and hour, which found that VRE curtailment occurred the most. Considering self- and cross-price elasticity of electricity, revised ToU tariff rate scenarios were used in a case study on Jeju Island. Eventually, it was confirmed that VRE curtailment could be mitigated when the revised ToU tariff rates were applied, considering the price elasticity of demand.

Author(s):  
Mohammad Omar Abdullah ◽  
Voon Chun Yung ◽  
Audra Anak Jom ◽  
Alvin Yeo Wee ◽  
Martin Anyi ◽  
...  

The eBario project has won the eAsia Award and the Mondialogo Engineering Award in 2004 and 2005 respectively for it’s successful implementation of an Information and Telecommunications Technology Center (ICT) and solar renewable energy-incentive rural community project at the Bario Highland of Sarawak, East Malaysia, Borneo (http://www.unimas.my/ebario/). Although solar photovoltaic (PV) energy has been opted for power generation at the ICT Telecenter for the past five years, there is still a need to investigate the cost-effectiveness of the current energy setup as well as to conduct sustainability study taking into account factors such as system efficiency, weather, costs of fuel, operating costs, as well as to explore the feasibility of implementing alternative energy resources for the rural ICT Telecenter. Recent theoretical study conducted has shown that renewable combined power systems are more sustainable in terms of supplying electricity to the ICT Telecenter, and in a more cost-effective way compared to a standalone PV system which is subject to the cloud and the recent dense haze problems. For that purpose, two combined power systems are being put into consideration namely PV-Hydro and PV-Hydro-Fuel Cell, where the total simulated annualized cost for these two system configurations are US$10,847 and US$76,010 respectively as far as the present location is concerned. The PVHydro-Fuel Cell produces electrical energy at the amount of 3,577 kWh/yr while the annual energy consumption is 3,203 kWhr/yr. On the other hand, PV-Hydro produces 3,789 kWhr/yr of electricity annually load which consumes energy at 3,209 kWhr/yr. Results thus obtained has shown that the PVHydro scheme is expected to have advantages over the existing PV standalone system. Firstly, it is more cost-effective. Secondly, it provides the best outcomes for the local indigenous community and the natural highland environments both for now and the future. Thirdly, it also able to relate the continuity of both economic and social aspects of the local society as a whole. As the combined PV-Hydro system had been chosen, plus for completeness purposes, the present paper also discussed the custom design and construction of a small waterwheel breast-shot hydro-generator, suited to the local location and existing water energy resources. Energy saving design calculations and Sankey diagram showing the energy flows for the new combined system are also given herein. Finally, the energy system performance equations and the performance curves introduced in this study provide a new simple method of evaluating renewable energy systems.


Stable operation of electrical power systems is one of the crucial issues in the power industry. Current vo­lumes of electricity consumption cause the need to constantly increase the generated capacity, repeatedly modifying and complicating the original circuit. In addition to this, given the current trend towards the use of digital power systems and renewable energy sources, more and more uncertainties difficult to predict by standard mathematical methods appear. Events in the power system are deterministic, i.e. random. Thus, it is difficult to fully assess the system stability, voltage levels, currents, or possible power losses. Finding the probability distribution laws can give us an understanding of all the possible states in which an object can exist. Obtaining them is complicated by the difficulty of accounting for all the correlations between the random arguments of the source data. These laws are necessary to determine the optimal operating modes, the possibility of solving the problem of determining the optimal renewable energy sources installation locations and the required amount of generated energy in a non-deterministic way. The purpose of this article is to test the developed SIBD method for obtaining the full probabilistic characteristics. This method, unlike the Monte Carlo methods, does not use a random sample of initial data, but completely covers the studied functional dependence. The problem was solved using the provisions of probability theory and mathematical statistics, numerical optimization methods in particular. The MATLAB Matpower application package was also used to solve technical computing problems.


2015 ◽  
Vol 735 ◽  
pp. 331-335
Author(s):  
Naila Zareen ◽  
Mohd Wazir Mustafa ◽  
Azriyenni

Environment deterioration, energy shortage and ever rising fuel price makes green transportation a necessity. Being an alternative to fossil fuels vehicles, Electric Vehicles (EVs) exemplify the most popular approach of electrification to a substantial portion of the transportation sector. Recently, usage of renewable energy resources (RERs) is also increased because of its economic and environmental concerns over traditional resources in the new electric power systems. Variable reliability aspects of RERs increase the complexity of safe and stable operation of grid. Therefore, EV will further increase this uncertainty and variability when being connected randomly to the grid in large scale. This paper not only highlights the EV’s related challenges/issues and presents a brief comprehensive review of recent researches. But, also demonstrates a simulation methodology for analyzing the impact of EVs under various charging scenarios on an independent distribution grid in presence of RERs. The results show the creation of new peak loads which in some cases may exceed the grid capacity and threaten the stability and reliability.


Author(s):  
Dr. Haoxiang Wang

In the recent days, energy mix performed by using the Renewable Energy Sources (RES) is gaining wide popularity. The control of predictability and generation takes a progressive loss as RES is penetrating increasingly in the energy mixes due to the non dispatchable nature of the energy produced from these sources. For ensuring and maintaining stable operation, the power system flexibility is increased when higher penetration levels are attained by RES. A Decision Support System (DSS) is used for energy conversion and storage systems which can be managed by an Information and Communication Technology (ICT) tool. The H2020 PLAnning and operational tools are used for optimizing energy flows and synergies between energy NETworks (PLANET) along with DSS for controlling the technology wherein power is converted into either heat or gas (P2X) by evaluation, management and dispatch. Further analysis is done in terms of energy evaluation and economic benefits with respect to P2X technology and its flexibility.


Author(s):  
S. G. Obukhov ◽  
I. A. Plotnikov ◽  
V. G. Masolov

The paper presents the results of the comparative analysis of operation modes of an autonomous hybrid power complex with/without the energy store. We offere the technique which defines the power characteristics of the main components of a hybrid power complex: the consumers of the electric power, wind power and photo-electric installations (the last ones have been constructed). The paper establishes that, in order to compensate the seasonal fluctuations of power in autonomous power systems with renewable energy resources, the accumulative devices are required, with a capacity of tens of MWh including devices that are capable to provide energy storage with duration about half a year. This allows abandoning the storage devices for smoothing the seasonal fluctuations in the energy balance.The analysis of operation modes of energy stores has shown that for a stock and delivery of energy on time intervals, lasting several hours, the accumulative devices with rather high values of charging and digit power aren't required. It allows using the lead-acid rechargeable batteries of the deep category for smoothing the daily peaks of surplus and a capacity shortage. Moreover, the analysis of operation modes of energy stores as a part of the hybrid complexes has demonstrated that in charging/digit currents of the energy store the low-frequency and high-frequency pulsations of big amplitude caused by changes of size of output power of the renewable power installations and loading are inevitable. If low-frequency pulsations (the period of tens of minutes) can partially be damped due to the restriction of size of the maximum charging current of rechargeable batteries, then it is essentially impossible to eliminate high-frequency pulsations (the period of tens of seconds) in the power systems with the only store of energy. The paper finds out that the combined energy store having characteristics of the accumulator in the modes of receiving and delivery of power on daily time intervals, and at the same time having properties of the supercondenser in the modes of reception and return of impulses of power on second intervals of time is best suited to requirements of the autonomous power complexes with renewable energy resources.


Author(s):  
Xu Pei-Zhen ◽  
Lu Yong-Geng ◽  
Cao Xi-Min

Background: Over the past few years, the subsynchronous oscillation (SSO) caused by the grid-connected wind farm had a bad influence on the stable operation of the system and has now become a bottleneck factor restricting the efficient utilization of wind power. How to mitigate and suppress the phenomenon of SSO of wind farms has become the focus of power system research. Methods: This paper first analyzes the SSO of different types of wind turbines, including squirrelcage induction generator based wind turbine (SCIG-WT), permanent magnet synchronous generator- based wind turbine (PMSG-WT), and doubly-fed induction generator based wind turbine (DFIG-WT). Then, the mechanisms of different types of SSO are proposed with the aim to better understand SSO in large-scale wind integrated power systems, and the main analytical methods suitable for studying the SSO of wind farms are summarized. Results: On the basis of results, using additional damping control suppression methods to solve SSO caused by the flexible power transmission devices and the wind turbine converter is recommended. Conclusion: The current development direction of the SSO of large-scale wind farm grid-connected systems is summarized and the current challenges and recommendations for future research and development are discussed.


Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 115
Author(s):  
Nasser Hosseinzadeh ◽  
Asma Aziz ◽  
Apel Mahmud ◽  
Ameen Gargoom ◽  
Mahbub Rabbani

The main purpose of developing microgrids (MGs) is to facilitate the integration of renewable energy sources (RESs) into the power grid. RESs are normally connected to the grid via power electronic inverters. As various types of RESs are increasingly being connected to the electrical power grid, power systems of the near future will have more inverter-based generators (IBGs) instead of synchronous machines. Since IBGs have significant differences in their characteristics compared to synchronous generators (SGs), particularly concerning their inertia and capability to provide reactive power, their impacts on the system dynamics are different compared to SGs. In particular, system stability analysis will require new approaches. As such, research is currently being conducted on the stability of power systems with the inclusion of IBGs. This review article is intended to be a preface to the Special Issue on Voltage Stability of Microgrids in Power Systems. It presents a comprehensive review of the literature on voltage stability of power systems with a relatively high percentage of IBGs in the generation mix of the system. As the research is developing rapidly in this field, it is understood that by the time that this article is published, and further in the future, there will be many more new developments in this area. Certainly, other articles in this special issue will highlight some other important aspects of the voltage stability of microgrids.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2301
Author(s):  
Yun-Sung Cho ◽  
Yun-Hyuk Choi

This paper describes a methodology for implementing the state estimation and enhancing the accuracy in large-scale power systems that partially depend on variable renewable energy resources. To determine the actual states of electricity grids, including those of wind and solar power systems, the proposed state estimation method adopts a fast-decoupled weighted least square approach based on the architecture of application common database. Renewable energy modeling is considered on the basis of the point of data acquisition, the type of renewable energy, and the voltage level of the bus-connected renewable energy. Moreover, the proposed algorithm performs accurate bad data processing using inner and outer functions. The inner function is applied to the largest normalized residue method to process the bad data detection, identification and adjustment. While the outer function is analyzed whether the identified bad measurements exceed the condition of Kirchhoff’s current law. In addition, to decrease the topology and measurement errors associated with transformers, a connectivity model is proposed for transformers that use switching devices, and a transformer error processing technique is proposed using a simple heuristic method. To verify the performance of the proposed methodology, we performed comprehensive tests based on a modified IEEE 18-bus test system and a large-scale power system that utilizes renewable energy.


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