Large-scale Photovoltaic Systems Research Articles

Financial Analysis of a Large-Scale Photovoltaic System and Its Impact on Distribution Feeders

To promote the photovoltaic (PV) installation, a large-scale PV system installed in the Main Stadium of the 2009 World Games has been investigated for the design of selling price of PV power generation. The PV power generation is simulated according to the hourly solar irradiation and temperature provided by the weather bureau. The cash flow of annual power generation, the O&M cost, and the capital investment cost of the PV system is then used to derive the payback years and the internal rate of return for the PV system under different selling price of PV power generation. The voltage variation and the power system loss of the distribution feeder, which serves the Main Stadium, are also performed by executing the 3-φ load flow analysis for the impact analysis of the PV system. The results indicate that the reduction of voltage drop and power system loss can be obtained with the PV system installed to provide the dispersed generation for the local loads. However, the PV system penetration is limited due to the violation of voltage variation introduced by the large intermittent PV power generation. The selling price of PV generation has to be designed according to the conditions of solar irradiation and temperature so that sufficient incentives can be provided to encourage more customers to participate the PV program.

대용량 PV 어레이의 최적설계에 관한 연구

Recently, a number of large-scale photovoltaic(PV) power generation system has been installed all over the world. Thus, in order to improve the system efficiency, the optimal design of the large-scale PV systems has become an important issue. DC cable loss of PV array is one of the design factors related to the system efficiency. This paper introduces the array design method of a 500kW Photovoltaic power plant. Three types of the PV array are suggested. Also, string cables, sub-array cables and array cables are designed within 1% of voltage drop in the line, and the DC cable losses are analyzed. The results of this paper show that the DC cable loss of large-scale PV array can be reduced by adopting a proper sub-array design method.

系統への影響を考慮した大規模太陽光発電システムの出力制御技術

系統への影響を考慮した大規模太陽光発電システムの出力制御技術

PV Fluctuation Balancing Using Hydrogen Storage – a Smoothing Method for Integration of PV Generation into the Utility Grid

This paper presents a method for using hydrogen storage to assist in integration of large scale photovoltaic (PV) generation system into the utility grid. An algorithm based on the simple exponential smoothing is used to suppress short term power fluctuations in PV generation. To facilitate economic dispatch by the system operator, the output of the exponential smoothing is held constant for a given dispatch interval. The more stable, step-wise constant power then acts as the power reference to be sent to the utility grid. The resulting power ripple (from the smoothing) and power error (from the step-wise forecast) is then absorbed by the hydrogen storage such that any PV power above the scheduled grid power curve is used to produce hydrogen using an electrolyzer and any power deficit is produced by a fuel cell. Simulation studies based on realistic irradiance data conducted in SIMULINK/SIMPOWER verifies the effectiveness of the developed method.

The costs and benefits of large-scale solar photovoltaic power production in Abu Dhabi, United Arab Emirates

The potential for a 10 MW photovoltaic power plant in Abu Dhabi is examined in this paper using RETScreen modeling software to predict energy production, financial feasibility and GHG emissions reductions. Initial results show high energy production potential, generating 24 GWh and saving over 10,000 tons of GHG emissions annually, but poor financial prospects yielding a net present value (NPV) of −$51 million. Benefits of reducing GHG and air pollution emissions by replacing natural gas with PV generation are calculated to have a net present value of $47 million, with a large range of possible values. Results show that the high initial costs and low expected price for electricity generated are driving reasons why photovoltaic systems are not being implemented in Abu Dhabi. A feed-in tariff rate of $0.16/kWh is recommended to make large-scale PV systems profitable.

Grid matching of large-scale wind energy conversion systems, alone and in tandem with large-scale photovoltaic systems: An Israeli case study

This paper presents a grid matching analysis of wind energy conversion systems (WECSs) and photovoltaic (PV)–WECS hybrid systems. The study was carried out using hourly load data of the Israel Electric Corporation (IEC) for the year 2006 and the corresponding simulated hourly performance of large PV and WECS plants in the Negev Desert. Our major objective was to compare the grid-matching capabilities of wind with those of our previously published PV results, and to assess the extent to which the combined employment of WECS and PV can improve the grid matching capability of either technology when used on its own. We find that, due to the differences in diurnal and seasonal output profiles of WECS and PV, their tandem employment significantly improves grid penetration compared to their use individually.

Erratum to: “Introducing very large scale PV systems in Israel”

Erratum to: “Introducing very large scale PV systems in Israel”

Energy from the Desert: Very Large Scale Photovoltaic Systems: Socio-economic, Financial, Technical and Environmental Aspects

Energy from the Desert: Feasibility of Very Large Scale Photovoltaic Power Generation Systems Background and Concept of VLS-PV ? World Energy Issues ? Environmental Issues ? An Overview of Photovoltaic Technology ? World Irradiation Database ? Concept of VLS-PV ? VLS-PV Case Studies ? General Information ? A Preliminary Case Study of VLS-PV Systems in World Deserts ? Gobi Desert ? Sahara Desert ? Middle East ? Scenario Studies and Recommendations Energy from the Desert: Practical Proposals for Very Large Scale Photovoltaic Systems Introduction ? The Mediterranean Region ? The Middle East Region ? The Asian Region ? The Oceania Region ? Desert Region Community Development ? Conclusions and Recommendations ? Bibliography, Index

Reactive Power Control Method for Reducing Voltage Fluctuation in Large-scale Photovoltaic Systems

For large-scale photovoltaic (PV) systems, we have developed a large capacity power conditioning system (PCS) with three functions: fault ride through function, harmonic reduction function and voltage control function. This paper deals with our new reactive power control method of the PCS for reducing voltage fluctuation in large-scale photovoltaic systems. The proposed method reduces the voltage fluctuation caused by the active power of PV by adjusting the power factor of the PCS automatically to the optimal value according to the conditions of power systems. In this paper, the control operation and the control effect of our proposed method were examined by numerical analysis and an experiment using small PCS models. We verified that the voltage fluctuation caused by output of PV at interconnecting point could be reducing by controlling reactive power at the optimal value according to the power system conditions. Then, we confirmed that there is no need to increase the PCS capacity by the adjusting the offset of the reactive power properly. Finally, we confirmed the voltage fluctuation could be reduced without biasing the reactive power to a specific PCS even if there is difference between outputs of plural PCSs operating in parallel.

Study of Evaluation Technique of PV System Performance by Output Analysis

The photovoltaic power generation system (PV system) has been expected as a clean energy source. However, it is supposed that the system reliability is not so high. In this study, the operational performance on large-scale photovoltaic power generation system was evaluated by using 12 systems. The standard rated output of each system was 4kW. As the results of the evaluation analysis, the rate of output deviation of System4 decreased 25% or less, in comparison with estimated output and the operation efficiency was unstable. It was obtained that the decrease of operation efficiency was caused by String3. From the results of inspections of the module, the solar radiation and the power conditioner, there was difference in conversion ratio between a DC-DC converter of a normal string and that of String3. The conversion ratio affected on the output of the string. It was able to find malfunction. Moreover, the regression analysis was investigated by using the output data of the PV system and irradiance. Performance of the PV system was evaluated using the regression coefficient. Stability of the PV system was also investigated using the method of this study.

Introducing very large scale PV systems in Israel

The paper introduces the discussion about possible application of very large scale PV systems in Israel. An application of very large scale PV production units of 100 and 500 MW, similar to the unit size of a conventional power station is proposed. A comparative evaluation between conventional power stations and PV stations is carried out in relation to the issues of: geographical location, fuel, pollution, sustainability, availability, watt construction cost and operational characteristics. Calculated payback shows that it decreases from 19 years in 2003 to about 4 years in 2020. Based on worldwide experience of the western countries it is recommended that the country should establish a national program to support the development of PV production and applications.

Road to very large scale photovoltaic power generation systems

Very large scale photovoltaic power generation (VLS-PV) systems are one of the promising options for large-scale deployment of PV systems. In the future, VLS-PV systems would be able to become an option for many large remote and desert regions in the world.

Testing the technologies

The penetration of photovoltaic (PV) systems in Japan has been on the rise. Two factors have been promoting the increase: improved generation efficiency of PV modules and governmental subsidies for the initial cost of residential PV generation systems. As a result, the cumulative installed PV capacity has increased exponentially; however, the cumulative installed PV capacity by 2007 was only about 40% of the target for 2010 (4,820 MW). Reaching the target and promoting larger installation capacities in the future will require further installation in the residential sector and the construction of large-scale PV systems. The New Energy and Industrial Technology Development Organization (NEDO) of Japan has conducted several demonstration projects to investigate technological issues regarding the large penetration of PV generation systems and to develop new technologies for using PV generation systems effectively. One of NEDO's demonstration grid-connected PV projects is the Ohta Project, a cluster of PV systems in a residential development. Another is the Wakkanai Project, the largest central-station PV system in Japan.

The Hokuto mega-solar project

Solar generation systems are one of the measures for reducing global warming. An installed capacity target of solar generation systems in our country will be set 4.82 GW in 2010, while the total installed capacity is still 1.92 GW in 2007. About 80% of the systems are mainly residential use and each is very small. Constructions of some large-scale solar generation systems will be expected and intensive development of related technologies are urgent. The New Energy and Industrial Technology Development Organization (NEDO) advertised for consignment research business “Verification of Grid Stabilization with Large-scale Photovoltaic (PV) Power Generation Systems” in 2006. The verification tests are carried out in two sites of Hokuto City, Yamanashi Prefecture and Wakkanai City, Hokkaido. The outlines and the developing targets and some of studying results of the Hokuto mega-solar project (HMSP) are introduced in this paper.

A study on collaborative operation method for a new energy type dispersed power supply system by AC-EMAP model

Application of a dispersed power supply system consisting of a large-scale photovoltaic system (PV), a fuel cell (FC), and an electric double layer capacitor (EDLC) is studied in this paper. This system is operated in autonomous mode, taking account of time delay characteristics of FC. The modified Euler type Moving Average Prediction (EMAP) model is improved using short-time fast Fourier transform (ST-FFT). The Adaptive Control type EMAP (AC-EMAP) model is introduced to reduce the capacity of EDLC. This system can meet the multi-quality electric power requirements of customers, and improve voltage stability and uninterruptible power supply (UPS) function as well. Moreover, the required capacity of EDLC to compensate the fluctuation of both PV output and Load demand is clarified by a simulation based on collaborative operation method by a prediction model using software MATLAB/Simulink. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(1): 13–24, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20262

適応制御型EMAPモデルによる新エネルギー型分散電源の連系運用手法に関する考察

Application of a dispersed power supply system consisting of a large-scale photovoltaic system (PV), a fuel cell (FC), and an electric double layer capacitor (EDLC) is studied in this paper. This system is operated in autonomous mode, taking account of time delay characteristics of FC. The modified Euler type Moving Average Prediction (EMAP) model is improved using short-time fast Fourier transform (ST-FFT). The Adaptive Control type EMAP (AC-EMAP) model is introduced to reduce the capacity of EDLC. This system can meet the multi-quality electric power requirements of customers, and improve voltage stability and uninterruptible power supply (UPS) function as well. Moreover, the required capacity of EDLC to compensate the fluctuation of both PV output and Load demand is clarified by a simulation based on collaborative operation method by a prediction model using software MATLAB/Simulink. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(1): 13–24, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20262

A Collaborative Operation Method Between New Energy-Type Dispersed Power Supply and EDLC

In this paper, the modified Euler-type moving average prediction (EMAP) model is proposed to operate a new energy type dispersed power supply system in autonomous mode. This dispersed power supply system consists of a large-scale photovoltaic system (PV) and a fuel cell, as well as an electric double-layer capacitor (EDLC). This system can meet the multi-quality electric power requirements of customers, and ensures voltage stability and uninterruptible power supply function as well. Each subsystem of this distributed power supply contributes to the above-mentioned system performance with its own excellent characteristics. Based on the collaborative operation methods by EMAP model, the required capacity of EDLC to compensate the fluctuation of both PV output and load demand is examined by the simulation using software MATLAB/Simulink, and, response characteristics of this system is confirmed with simulation by software PSIM.

A study of collaborative operation between a new energy type dispersed power supply system and SMES by modified Euler type moving average prediction model

AbstractIn this paper, the modified Euler type Moving Average Prediction (EMAP) model is proposed in order to operate a dispersed power supply system using new energy in autonomous mode. Furthermore, the EMAP model is used to operate a new type of dispersed power supply system consisting of a large‐scale photovoltaic system (PV), a fuel cell (FC), and a small‐scale superconducting magnetic energy storage system (SMES). This distributed power supply system can meet the multiple‐quality electric power requirements of customers, and ensures voltage stability and UPS (Uninterruptible Power Supply) functions as well. Each subsystem of this distributed power supply contributes to the above‐mentioned system performance with its own excellent characteristics. Moreover, the response characteristics of this system are confirmed by simulation with PSIM software, and, using collaborative operation under the EMAP model, the required capacity of SMES to compensate the fluctuation of both PV output and load demand is examined by simulation, using MATLAB/Simulink. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 147(2): 1–12, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10318

Case studies of large-scale PV systems distributed around desert area of the world

To show the huge potential of PV systems, the authors have been studying the feasibility of large-scale PV plants. If a PV module cost is assumed to be 100 ¥ W , it gives the electricity at a cost of 7.70−13.12 ¥ kWh for a 100 MW plant size located at 6 desert sites around the world, considering the site irradiation,local labor cost, etc. for each site. In spite of the fixed, flat plate, the cost can reach a fairly low level. The station will be composed of 20 sub-units × 10 units of 500 kW optimum size sub-units.

97/03905 Impacts of large scale photovoltaic systems on the low voltage network

97/03905 Impacts of large scale photovoltaic systems on the low voltage network