PV powered universities literature review/Energy cost calculations for a solar PV Home System

Energy cost calculations for a solar PV Home System[1][1][1][1][1][14][14][27][27][edit | edit source]

Abstract Energy costing for a Solar Home System has been presented here considering the main cost components. It has been identified that the cost of solar PV panels, bank interest rate, cost of battery and its longevity plays the most important role in determining the energy cost. Average solar insolation is also taken into consideration and the results show that contribution of the storage battery towards the total cost of energy is significantly higher than that of the solar PV panel.

• The cost of solar PV energy in a Solar Home System is unlikely to reduce to a level where it may become competitive to the grid power
• 85% efficiency of a battery approximately increases the energy cost by 15%

The PV grid-connected demonstration system of University #x201C;Politehnica #x201D; of Bucharest[2][2][2][2][2][15][15][28][28][edit | edit source]

Abstract In 2006, at University Politehnica of Bucharest, in the framework of the European demonstration project PV-enlargement, and of the Romanian project ldquoPV gridrdquo, a rooftop grid-connected photovoltaic power generation system of 30 kWp has been installed. This is a double array PV system containing two kinds of silicon modules: crystalline and amorphous. The installed power of crystalline modules is of 27.36 kWp and that of amorphous modules is of 3.24 kWp. This paper gives a survey of amorphous silicon array performances during 12 representative working months under specific operational and environmental conditions of Bucharest geographical location.

• A central data monitor which monitors the health of the entire system, collects the data from inverters about its operating parameters
• The monitoring system is connected to a PC from which monitors operation of inverters, energy input and output, and historical file of the electric performances
• Data acquisition system measures solar irradiation, module temperature, air temperature, power and energy produced of each inverter, and so on
• Data are retrieved from the monitoring equipments at regular intervals of 10 minutes, and submitted immediately to quality control and data analysis through remote access via internet
• The biggest temperature differences between panels and environment are in summer time, about 15 degree Celsius as average value

Cost boundaries for future PV solar cell modules[3][3][3][3][3][16][16][29][29][edit | edit source]

Abstract Growth of the photovoltaic (PV) market is still constrained by high initial capital costs of PV. Developments in PV technologies may lead to cheaper systems at the likely expense of life expectancy and efficiency. Cost boundaries are required for future PV technologies to compete effectively within the current PV market. This paper develops a methodology based on life-cycle costing and sensitivity analysis to determine cost boundaries for new PV technologies. Amongst other comparisons with existing PV systems, the upper wattpeak cost bounds are estimated and the minimum economically viable replacement period is illustrated. Furthermore, future PV system ratings are compared to current PV systems for similar energy outputs. The results show that a price reduction factor greater than 5 is competitive for future solar cell lifetimes of less than 4-5 years. Meanwhile, future PV systems were, on balance, found to have higher ratings compared to current PV systems of similar energy outputs. The potential application of the model developed in this work is also discussed.

• Efficiency degradation of PV modules have been considered linear in this work, most of the manufacturers guarantee 80% of initial efficiency after 20-25 year period
• Inflation and discount rate have been considered fix throughout the entire timeframe
• PV systems less than 3Kwp are considered suitable for domestic building integrated_PV systems

MATLAB-Based Modeling to Study the Effects of Partial Shading on PV Array Characteristics[4][4][4][4][4][17][17][30][30][edit | edit source]

Abstract The performance of a photovoltaic (PV) array is affected by temperature, solar insolation, shading, and array configuration. Often, the PV arrays get shadowed, completely or partially, by the passing clouds, neighboring buildings and towers, trees, and utility and telephone poles. The situation is of particular interest in case of large PV installations such as those used in distributed power generation schemes. Under partially shaded conditions, the PV characteristics get more complex with multiple peaks. Yet, it is very important to understand and predict them in order to extract the maximum possible power. This paper presents a MATLAB-based modeling and simulation scheme suitable for studying the I-V and P-V characteristics of a PV array under a nonuniform insolation due to partial shading. It can also be used for developing and evaluating new maximum power point tracking techniques, especially for partially shaded conditions. The proposed models conveniently interface with the models of power electronic converters, which is a very useful feature. It can also be used as a tool to study the effects of shading patterns on PV panels having different configurations. It is observed that, for a given number of PV modules, the array configuration (how many modules in series and how many in parallel) significantly affects the maximum available power under partially shaded conditions. This is another aspect to which the developed tool can be applied. The model has been experimentally validated and the usefulness of this research is highlighted with the help of several illustrations. The MATLAB code of the developed model is freely available for download.

• Characteristics of an array with bypass and blocking diodes differ from that of an array without these diodes
• Blocking diodes prevent reverse current through the series assemblies, which generate lower output voltage in comparison with the others connected in parallel
• In order to feed the generated power by solar panels to the grid, a boost-type dc/dc converter and an inverter are used
• If the likely shading pattern on the PV array is known, the simulation model is handy to design the most optimum configuration of the PV array to extract the maximum power
• Some software packages can be used to model the effects of shading such as PV-Spice, PV-DesignPro, SolarPro, PVcad, and PVsyst

Autonomous PV system to applications in the Eastern of Mexico[5][5][5][5][5][18][18][31][31][edit | edit source]

Abstract It is particularly important to evaluate the properties of the generation system in the actual operating conditions in order to get a real picture of the amount of electricity which could be generated. The Eastern of Mexico is a region with a significant amount of solar radiation potentially useful for PV applications. Thus, the Energy Laboratory of the University of Yucatan developed an autonomous photovoltaic generator to evaluate the operational performance of a stand-alone PV system in the local environmental conditions. The system created allows monitoring the patterns produced by the generation, storage and consumption of the electrical power to study the transport of energy along the whole system. On the other hand, the solar radiation and the temperature were also monitored because of their impacts on the PV generation pattern.

• The main systems installed in the container comprise the energy storage system, the monitoring system, and the inverter and charge controller
• A charger controller was connected between the PV panel and the batteries bank in order to avoid overcharge situations
• The inverter prevents from extreme cycles of over-discharge extending the batteries lifetime
• The PV panel is installed on a structure with a rotation axis; therefore, the inclination angle for the PV panel can be easily changed
• The temperature sensor is installed on the back of a PV module while the solar radiation sensor is fitted with same inclination angle at the edge of the PV panel
• Environmental sensors such as solar radiation sensor, temperature sensor, and wind speed and wind direction sensors are installed on top of a 6m height tower

Monitoring and analysis of research PV Modules at University of West Bohemia in Pilsen and in the Czech Republic[6][6][6][6][6][19][19][32][32][edit | edit source]

Abstract In this time, there is a great press on the environment protection, in order the emission of the classic fossil fuels should be reduce. Therefore the higher utilization of the renewable power sources is expanding all over the world. The utilization of the solar radiation for the electricity production by the photovoltaic generators is one of the production way with high regardful of the environment protection. The paper deals with the experience of the PV operation and results in the Czech Republic (CR). Next, the University of West Bohemia (WBU) in Pilsen research activities on the field of PV research systems is discussed.

• The angle has a great influence on the total daily production of PV, but cleaning modules has a low influence on the PV production
• The difference between the production of the module with the angle 35 and 60 degrees is approximately 20%, and the difference between 35 and 45 degree is about 10%

Product-integrated PV applications - How industrial design methods yield innovative PV powered products[7][7][7][7][7][20][20][33][33][edit | edit source]

Abstract Given the high potential of PV technology to reduce the environmental impact of electricity use of products, it would be worthwhile to advance the integration of PV systems in mass produced products. We assume that industrial design engineering (IDE) could play a crucial role in making PV technology fit for product applications by its focus on functionality and usability. IDE might have an added value to existing R&D of PV technology which emphasizes on increased performance and decreased production cost of PV cells and modules. Therefore, in this paper, we will assess how industrial design methods might favour the development of product-integrated PV applications. In our project product designers have conceptually designed 17 products with integrated PV cells. The project took place in 2007 at the School of Industrial Design Engineering of University of Twente in the Netherlands. During the design process several innovative design methods were applied, among which the innovation phase model, lead user studies, platform driven product development, risk diagnosis, technology road mapping, TRIZ, innovative design and styling, innovation journey and constructive technology assessment. By observing 17 PV-powered products which resulted from the project we evaluated the innovative effect of industrial design methods on product-integrated PV applications. The application of IDMs resulted in a broad range of varied innovative PV-powered product concepts ranging from small products, like electronic handhelds, to middle-sized products like toys and portable fridges, to big-sized objects such as building-integrated PV elements and a zeppelin. The results show that the use of carefully chosen and applied industrial design methods can help to better integrate PV technology in products.

• The main reason for the reduction battery use in products are considered to be cost and environmental issues
• Batteries cause a lot of user interventions
• Product-integrated PV systems can reduce the required capacity of batteries and the number of user interventions associated with battery use

Modelling, simulation and performance analysis of a PV array in an embedded environment[8][8][8][8][8][21][21][34][34][edit | edit source]

Abstract Photovoltaic (PV) generation involves the direct conversion of sunlight into electrical energy. In recent years it has proved to be a cost-effective method for generating electricity with minimum environmental impact. Due to the environmental and economic benefits PV generation is now being deployed worldwide as an embedded renewable energy source and extensive research is being performed in order to study and assess the effectiveness of PV arrays in Distributed Generation (DG) systems either as a potential energy source or as energy reserve in combination with other types of distributed energy resources. This paper presents the modeling and MATLAB simulation of a stand-alone polycrystalline PV Array system and investigates load following performance efficiency under various loading and weather conditions as well as suitability with regard to enhancing power supply reliability to critical loads. The modeling of the PV array that has been performed in this research using MATLAB Simulink is based on the calculation of parameters for the Thevenin's equivalent circuit of each cell of the array. The standard double exponential polycrystalline cell model has been adopted for this research with solar irradiance E and ambient temperature T as the input and Thevenin's voltage Vthar and Thevenin's resistance Rthar as the output.

• Each cell of the PV array has been modeled as a Thevenin's equivalent circuit comprising Thevenin's voltage and resistance

Performance evaluation and analysis of 50kW grid-connected PV system[9][9][9][9][9][22][22][35][35][edit | edit source]

Abstract This paper summarizes the results of these efforts by offering a photovoltaic system structure in 50 kW large scale applications installed in Chosun University dormitory roof. The status of PV system components, are inter-connection and safety equipment monitoring system will be summarized as this article. This describes configuration of utility interactive photovoltaic system which generated power supply for dormitory. In this paper represent 50 kW utility PV system examination result.

• PV systems are easy to maintain, the life cycle is long, and the installation is easy

Road to cost-effective crystalline silicon photovoltaics[10][10][10][10][10][23][23][36][36][edit | edit source]

Abstract The cost of photovoltaics (PV) is expected to decrease by a factor of two to four within the next two decades, making PV a very attractive and cost-effective solution to the problems of fossil fuel depletion and growing energy demand. Crystalline Si has been the champion of the PV industry, providing an average growth of greater than 30%/yr in the last six years, in spite of stiff competition from other materials and technologies. Si has the uncanny ability to reinvent itself when challenged. This paper describes how Si is responding to the challenge of cost- effective PV via thinner and lower-cost substrates, low-cost technology development, higher manufacturable cell efficiencies, and proven reliability and scalability. Cost and technologies roadmaps are developed that show 17-18% efficient cells on 150-200-/spl mu/m thick wafers can reduce the manufacturing cost below $1/W for a 100-500 MW production facility.

• The current direct manufacturing cost of Si modules has reached $1.98/W and it can become less than $1/W in order to compete with traditional energy sources
• To have a cost of $1/W we need a 150-200 micro meter thick, 17-18% efficient cells with 100-500 MW production lines
• The cost reduction can be achieved with thinner Si substrate, modest bulk lifetime, better back surface passivation, improved screen printing, and surface texturing

A cost analysis of very large scale PV (VLS-PV) system on the world deserts[11][11][11][11][11][24][24][37][37][edit | edit source]

Abstract To preserve the Earth, a 100 MW very large-scale photovoltaic power generation (VLS-PV) system is estimated assuming that it is installed on the world deserts, which are Sahara, Negev, Thar, Sonora, Great Sandy and Gobi desert. These deserts are good for installing the system because of large solar irradiation and large land area. A PV array is dimensioned in detail in terms of array layout, support, foundation, wiring and so on. Then generation cost of the system is estimated based on the methodology of life-cycle cost (LCC). As a result of the estimation, the generation cost is calculated as 5.3 cent/kWh on Sahara desert, 6.4 cent/kWh on Gobi desert assuming PV module price of $1.0/W, system lifetime of 30 years and interest rate of 3%. These results suggest that VLS-PV systems are economically feasible on sufficient irradiation site even if existing PV system technologies are applied, when PV module price will decrease to a level of $1.0/W.

• The purpose is to design a VLS-PV system on major world deserts and to investigate its feasibility from an economic viewpoint
• To evaluate the potential of VLS-PV system in detail, generation cost of VLS-PV system has been estimated in consideration of a methodology of Life-Cycle cost which is manufacture and transportation of system components, system construction and operation
• Designing procedures of VLS-PV system has been divided into several steps: PV module layout, array support design, foundation design, and wiring

Steady-state performance of a grid-connected rooftop hybrid wind-photovoltaic power system with battery storage[12][12][12][12][12][25][25][38][38][edit | edit source]

Abstract This paper reports the performance of a 4-kW grid-connected residential wind-photovoltaic system (WPS) with battery storage located in Lowell, MA, USA. The system was originally designed to meet a typical New-England (TNE) load demand with a loss of power supply probability (LPSP) of one day in ten years as recommended by the Utility Company. The data used in the calculation was wind speed and irradiance of Login Airport Boston (LAB) obtained from the National Climate Center in North Carolina. The present performance study is based on two-year operation. (May 1996-Apr 1998) of the WPS. Unlike conventional generation, the wind and the sunrays are available at no cost and generate electricity pollution-free. Around noontime the WPS satisfies its load and provides additional energy to the storage or to the grid. On-site energy production is undoubtedly accompanied with minimization of environmental pollution, reduction of losses in power systems transmission and distribution equipment, and supports the utility in demand side management. This paper includes discussion on system reliability, power quality, loss of supply and effects of the randomness of the wind and the solar radiation on system design.

• Due to aging, some modules may experience some discoloration over time from blue to brown due to oxidation which occurs at high temperatures between the actual solar cells and the front glass cover, and it reduces the module's efficiency
• Linear modeling and Neural networks are used to predict PV performance under various temperature, and wind conditions
• A converter rectifies the alternating current generated by the wind generator and protects the batteries from being overcharged by wind turbine
• The air along the coastline is subject to higher temperature differences than air in land due to absorption differences between land and water

Universidad Verde-200 kWp grid connected PV system[13][13][13][13][13][26][26][39][39][edit | edit source]

Abstract This project consists in the installation of four photovoltaic subgenerators connected to the low voltage grid at Jaen University Campus (Spain), with a total power of 200 kWp. The Univer Project is developed under the Thermie Programme of the EU, with a budget of about 1.8 M euros. The main objective is the integration of a medium scale PV plant using different architectural solutions. This project presents two innovative aspects: on the one hand, the development of the technology necessary to implement medium-high scale PV plants in crowded places, mainly focused on safety and protection systems; on the other, the development and analysis of different architectural solutions to integrate PV generators using constructive structures easily replicable.

• In order to protect people, installation includes a floating system configuration, a cover of wiring, a permanent insulation controller to detect the earth faults of the generators, and an earth grid
• Some operating problems may occur in installation of PV, for instance, a current harmonic can be introduced by inverter which can cause interference
• A permanent insulation controller can be used to detect the loss of the system insulation

Advances in PV semiconductor materials and technology[14][14][14][14][14][27][27][40][40][edit | edit source]

Abstract It is now accepted that photovoltaics is the most promising of the renewable energy sources for electric power generation. Photovoltaic's ability to provide reliable, high grade energy over an extended lifetime is now well proven in both space and terrestrial applications. Widespread adoption of this clean, silent power source, however, still awaits the achievement of a number of outstanding technical and economic objectives. Extensive research into photovoltaic technology over the last two decades has done enough to conclude that all these goals can be met. The present challenge is to apply these results industrially and commercially so as to make the dream and reality. Photovoltaics can only provide an efficient service to its users if it provides a transparent and trouble free source of electricity. This involves the application of photovoltaic devices in well integrated systems which also include appropriate mechanical and electrical interfaces. The author focuses on one part of the system-the photovoltaic generator itself. This paper reviews the status of international developments and the contributions which they can make in achieving this objective.

• Commercially available crystalline solar cells are typically of the order of 15% efficient. Laboratory cells have achieved higher efficiencies, up to over 23 %, but these, in most cases, incorporate embelishments which cannot be considered cost effective. The higher efficiency cells on the market use advances such as laser recessed contact grids and textured surfaces to increase efficiency to about 18 %
• Silicon is not the only material which can be deposited in photovoltaically active thin films. There are a number of other thin films which are also the subject of active research work. Most of these involve compound materials and probably the most actively pursued are copper indium diselenide (CIS), copper indium gallium diselenide

(CIGS) and cadmium telluride (CdTe)

Design, performance and cost of energy from high concentration and flat-plate utility-scale PV systems[15][15][15][15][15][28][28][41][41][edit | edit source]

Abstract This paper presents the results of a recent study to assess the near-term cost of power in central station applications. Three PV technologies were evaluated: Fresnel-lens high-concentration photovoltaic (HCPV);, central receiver HCPV; and flat-plate PV using thin-film copper indium diselenide (CIS) cell technology. Baseline assumptions included PV cell designs and performances projected for the 1995 timeframe, 25 and 100 MW/year cell manufacturing rates, 50 MW power plant size, and mature technology cost and performance estimates. The plant design characteristics are highlighted. Potential sites were evaluated and selected for the PV power plants and cell manufacturing plants. Conceptual designs and cost estimates were developed for the plants and their components. Plant performance was modeled and the designs were optimized to minimize levelized energy costs. Cost estimates for both plant and energy delivered include effects of uncertainty in key parameters. Although the study did not involve detailed engineering, efforts were made to optimize all of the plant designs and minimize levelized energy costs. Cell and module fabrication processes were also developed.

• The cell technology selected for the flat-plate plant is thin-film copper indium diselenide (CIS). The layers of the CIS cells are deposited on a glass substrate in a bottom to top sequence. The 2 micron thick cells are 5.8 mm wide overall, including a 4 mm active-area width in the voltage direction, and extend the length of the module in the current direction
• The CIS module consists of a laminated layup of a non- tempered glass suhstrate, cell layer depositions, EVA and a low-iron glass superstrate. Silicone and a plastic extrusion form the edge seal. The module is 2.4 by 5 feet. The module's active area efficiency is 13 percent and its efficiency is 12.7 percent based on an overall outside area of 1.103 m2, at standard test conditions of 1 kW/m irradiance and 25'C cell temperature

References[edit | edit source]