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Solar photovoltaics (PV) is the dominant type of distributed generation (DG) technology interconnected to electric distribution systems in the United States, and deployment of PV systems continues to increase rapidly. Considering the rapid growth and widespread deployment of PV systems in United States electric distribution grids, it is important that interconnection procedures be as streamlined as possible to avoid unnecessary interconnection studies, costs, and delays. Because many PV interconnection applications involve high penetration scenarios, the process needs to allow for a sufficiently rigorous technical evaluation to identify and address possible system impacts. Existing interconnection procedures are designed to balance the need for efficiency and technical rigor for all DG. However, there is an implicit expectation that those procedures will be updated over time in order to remain relevant with respect to evolving standards, technology, and practical experience. Modifications to interconnection screens and procedures must focus on maintaining or improving safety and reliability, as well as accurately allocating costs and improving expediency of the interconnection process. This paper evaluates the origins and usefulness of the capacity penetration screen, offers potential short-term solutions which could effectively allow fast-track interconnection to many PV system applications, and considers longer-term solutions for increasing PV deployment levels in a safe and reliable manner while reducing or eliminating the emphasis on the penetration screen.

This white paper evaluates the origins and usefulness of the capacity penetration screen, offer short-term solutions which could effectively allow fast-track interconnection to many PV system applications, and considers longer-term solutions for increasing PV deployment levels in a safe and reliable manner while reducing or eliminating the emphasis on the penetration screen. Short-term and longer-term alternatives approaches are offered as examples; however, specific modifications to screening procedures should be discussed with stakeholders and must ultimately be adopted by state and federal regulatory bodies.

While the number of PV systems interconnected to the electric grid has increased significantly over the last decade, only recently have PV systems been installed in major metropolitan areas and tied to electric distribution secondary network systems (networks). This paper examines six cases studies of photovoltaic (PV) systems integrated into secondary network systems. The six PV systems were chosen for evaluation because they are interconnected successfully to secondary network systems located in four major U.S. Cities.

The heat transfer coefficients of porous copper fabricated by the lost carbonate sintering (LCS) process with porosity range from 57% to 82% and pore size from 150 to 1500 μm have been experimentally determined in this study. The sample was attached to the heat plate and assembled into a forced convection system using water as the coolant. The effectiveness of the heat removal from the heat plate through the porous copper-water system was tested under different water flow rates from 0.3 to 2.0 L/min and an input heat flux of 1.3 MW/m2. Porosity has a large effect on the heat transfer performance and the optimum porosity was found to be around 62%. Pore size has a much less effect on the heat transfer performance compared to porosity. High water flow rates enhanced the heat transfer performance for all the samples.

In January of 2003, the Florida Department of Environmental Protection/Florida Energy Office (DEP/FEO) allocated $600,000 in hardware funds toward the installation of photovoltaic (PV) solar systems on Florida schools. As a result of this program, grid-connected PV systems less than six kilowatts in size were installed on 29 schools in the State of Florida. The Florida Solar Energy Center (FSEC) has monitored these systems for approximately one year of operation. The performance of 28 of these systems was analyzed using standard performance parameters such as the performance ratio, PV array efficiency, inverter efficiency, and PV system efficiency. In addition, a life-cycle cost analysis was conducted using new cost data values and updated market assumptions. These data will serve as a benchmark to compare against future systems with respect to performance vs. installed system cost.Copyright © 2006 by ASME

The Florida Solar Energy Center (FSEC) has partnered with Sandia National Laboratories (SNL), the Southwest Technical Development Institute (SWTDI), and the California Energy Commissions Public Interest Energy Research (CEC PIER) in an effort to characterize the performance of PV inverters operating over extended periods of time. As part of this characterization, SNL executed an initial performance characterization in the laboratory to be repeated at one or two year intervals. These inverters were then sent distributed to the above test facilities for installation and long-term testing. To perform this long-term testing, FSEC built an inverter test facility made up of a configurable 10.1 kW PV array and four test beds. Each test bed was set up to monitor the following parameters: DC voltage, DC current, AC Voltage, AC Power and inverter temperature. Solar irradiance, ambient temperature, and several PV array temperatures were recorded by a separate, synchronized datalogger. Three inverters are currently being tested: the Fronius IG 3000, the Xantrex GT 3.0, and the SMA Sunny Boy 2500U. The three inverters were loaded with a PV array close to the maximum power limit allowed by the inverter, and the array power supplied to each inverter was within 100 W of one another. Since the PV array for each inverter used identical PV modules mounted in the same orientation, it was easier to develop a model to compare inverter performance based on energy output. In addition to energy output, other parameters were obtained such as inverter efficiency. An attempt was made to compare the results obtained at FSEC to those results compiled by the California Energy Commission.Copyright © 2006 by ASME

This analysis expands the photovoltaic (PV) life cycle cost (LCC) results presented at ASES 2004. That paper presented the model and concept used to develop PV LCC, and it showed the results of the analysis of over one hundred systems monitored by the Florida Solar Energy Center (FSEC). FSEC began tracking cost, performance and reliability data for systems installed in Florida in 1998, with data now available through a web-accessible database. For the majority of the 124 systems, installed cost information was collected as part of the state’s PV rebate and PV for schools programs. Results presented previously [1] indicated that over an assumed 20–30 system life time a PV system will have a positive life cycle cost. That is, a negative total return on investment. These results were based on actual cost, performance, maintenance, and reliability data. In the baseline case, average total system costs over the lifetime were 32.4¢/kWh while electricity savings totaled 3.7¢/kWh netting a life cycle cost of 28.7¢/kWh. While based on actual data from over 100 installed systems — some installed for over 6 years — a number of conservative assumptions also drove the analysis, such as the exclusion of the state’s rebate programs (varying from $2 to $5 per DC Watt) which impacted nearly all of the systems in the analysis. Since the first presentation of these results the PV LCC model has been further developed to incorporate additional performance information and expands the sample of systems incorporated. This paper will thus provide further insight into the relative importance of various up-front and on-going costs to the overall lifetime economics of a system. The paper will also address additional sensitivity analysis performed. Particular attention is paid to inverter mean time between failure (MTBF), the impact of incentives, and basic financial assumptions used in the model such as the discount rate and electricity rates. Various scenarios are considered in asking the question of what is necessary for the system LCC to break-even.Copyright © 2005 by ASME

Between April 2001 and September 2002, the Florida Solar Energy Center conducted research to evaluate the performance of several utility-interactive inverters. The major issues to be identified were the efficiency of the inverters and their ability to follow the maximum power point of the photovoltaic (PV) array. Existing PV testing facilities at FSEC were modified to carry out this analysis. This facility, called the Photovoltaic Inverter Test Facility, is capable of providing approximately four kWp of array power to the inverter. Data on inverter performance were collected using a Campbell 10X datalogger. The parameters collected included the following: irradiance, PV array temperature, inverter temperature, PV voltage, PV current, AC voltage, AC current, and AC Power. Because of the voltage windows and power requirements of the different inverters, the array was designed to be easily reconfigured to meet those requirements. Each of the inverters was installed and allowed to run for several weeks under both clear and cloudy conditions. At the end of the test period, inverter efficiencies were calculated from the collected data. The ability of the inverter to follow the maximum power point of the array was evaluated in two ways. In the first method, DC voltage and current were measured while the inverter was operating, then the array was disconnected from the inverter and the maximum power point of the array was immediately taken. By comparing the measured DC voltage and current to the maximum power point of the array, one could determine the effectiveness of the inverter algorithm. Unfortunately this method requires steady-state conditions and does not show the effectiveness of the algorithm in cloudy conditions. To determine its effectiveness in cloudy conditions, DC voltage and current were compared to the expected maximum power. The expected array maximum power point was calculated from IV curves of the array, irradiance measurements, and array temperature measurements. DC to AC efficiency curves were derived from the data as well. Results from the inverters were mixed, but several showed room for improvement.

The Florida Solar Energy Center has been accredited by both the American Association for Laboratory Accreditation and PowerMark Corporation to certify grid-tied photovoltaic systems. The certification process involves both the testing of photovoltaic modules for performance ratings and the review and approval of system designs to provide photovoltaic system design certification. This paper focuses on the design review and approval process, which consists of a documentation review and focuses on the completeness and accuracy of instructions, schematics, and accompanying materials. System designers have received substantive critiques and assistance through the third-party technical reviews used in this process. As a result, photovoltaic system manuals that accompany reviewed systems lead to a greater likelihood of code-compliant and high-performing installations.

Novel two-stage Se vapor selenization of magnetron sputtered metallic precursors and Ga incorporation using single Cu-Ga(22 at.%) alloy target have been developed for preparation of well-adherent, large, compact, well-faceted polyhedral grain CuIn/sub 1-x/Ga/sub x/Se/sub 2/ thin films having optimum composition Cu:In:Ga:Se of 22.95:25.03:1.40:50.63. Cu-In-Ga precursor homogenization by in situ heat-treatment at /spl sim/90/spl deg/C for 10 minutes prior to first selenization, selenization temperature of 550-560/spl deg/C, and Se vapor incidence rate of 50 /spl Aring/ sec/sup -1/ resulted in improved morphology of completed CuIn/sub 1-x/Ga/sub 2/Se/sub 2/ thin films, and solar cells with open circuit voltage V/sub oc/ 377 mV, short circuit current density J/sub sc/ of 34.8 mA, fill factor (FF) of 62.5%, active area efficiency of 8.2% (total area efficiency 5.8% limited by FF 49.1%) and fairly constant spectral response over the spectral range.

A new method for timing recovery and delay-spread estimation in OFDM systems is proposed. The method uses the correlation between the cyclic extension and data portion of the received OFDM symbols to estimate timing. Although cyclic extension based timing estimation methods have been proposed earlier, the present scheme is unique in the way the correlation is computed and used to estimate timing. The method identifies the complete range of ISI-free sampling positions available in an OFDM symbol, instead of identifying just one of them randomly. Further, the delay-spread information provided by the method can be used to improve the BER performance of the system by adjusting the frequency-domain interpolation filter bandwidth.

The lack of consistently high performance from inverters has created numerous issues in the widespread application and confidence in grid-tied photovoltaic systems. Additionally, the lack of a metric by which inverter manufacturers can evaluate their products presents a challenge to manufacturers by not allowing them to distinguish their products from those of their competitor, and to users since there is no way of comparing seemingly-similar models. This problem is further compounded by the dearth of inverters that have high performance and reliability [1]. This document is the first draft of a test protocol under development at the Florida Solar Energy Center to assist in this area. A need for such a test protocol has been recognized nationally, and it is hoped that this document may provide a foundation for future test procedures while providing significant and reasonable findings in the interim.Copyright © 2002 by ASME

One of the goals of the Florida PV Buildings Program is to ensure that only quality utility-interactive PV systems are installed in the state. One important component of the Program is the site survey. The purpose of the site survey is to inspect the potential location for PV system before beginning construction, ensuring it is a sensible place to install it. The purpose of this paper is to introduce the method used by this Program and to present some examples that will demonstrate why it is important.

This project sought to develop a team-based ministry with the staff at Cadiz Baptist Church in Cadiz, Kentucky. Chapter 1 describes a proposal for team based ministry using goals, a church and community context, and the rationale for the project. Chapter 2 examines the biblical and theological principles of team leadership focusing on the ministry of Jesus. Chapter 3 explores the benefits of effective teamwork, including choosing a team, developing a team, and common denominators between effective secular teamwork and effective team-based ministry in a local church. Chapter 4 gives details of the actual implementation of the project, including a personality test, a spiritual gifts test and question, questions from books, and meetings with an independent group of church leaders. Chapter 5 reviews the effectiveness of the project. The data is analyzed and the goals and process are evaluated.

A Cu-Ga(66 at. %) alloy target was employed for enhancing the gallium content in CuIn1−xGaxSe2 films prepared by two Se-vapor selenizations of metallic precursors. Combination with a Cu-Ga(22 at. %) sputtering target allowed preparation of CuIn1−xGaxSe2 films with a graded profile. Gallium content Gax near the surface was raised to the range 0.28–0.32, while an even higher amount of gallium of up to 0.40 was obtained in the bulk of the films. Efficiency of solar cells prepared from CuIn1−xGaxSe2 films with moderately enhanced gallium content was 8.5%. Higher gallium proportions seem to be correlated with the formation of Cu-rich phases, surface inhomogeneities, and possibly a highly resistive phase. This combined with inferior crystallinity deteriorated solar cell efficiency.

The field of photovoltaics has undergone dramatic growth over the past few years. This growth has been accompanied by two significant changes in the commercial photovoltaic (PV) market. 1.The major PV market has shifted from the residential and commercial building markets to central station utility power markets. With this switch has come a new focus on the long-term reliability and durability of PV modules and systems. If you are installing tens or even hundreds of megawatts of PV modules, it is absolutely necessary to ensure that they will continue to perform adequately throughout their expected lifetime of at least 25 years. 2.Selling prices for PV modules have decreased from more than $4 per watt to less than $1 per watt in the last 5 years. This reduction in selling process has been driven by low-cost production in the developing world. This means that most of today's PV modules are being manufactured by companies that did not exist 10 or, in many cases, even 5 years ago. Yet the modules must carry 25-year warranties and are expected to survive at least that long without having the benefit of long-term field experience.

A new biomass fueled electricity generation plant is now under construction in Gainesville, Florida and serves as an excellent subject as it demonstrates the surprising ways the credit ratings agencies influence ecological modernization. Through content analysis, participant observation, and document analysis I will illustrate how credit ratings agencies have influenced the ecological modernization of one of the United States' approximately 2000 municipal electricity utilities.

This article looks at issues of recreancy, environmental justice, and relocation as they relate to a flood control infrastructure project in inner city Houston. The main research questions were “What forms would recreancy take?” and “Can a project be environmentally just if recreancy is present?” Through the structural coding of 53 semi-structured interviews, recreancy was found even in a project where the sponsors used community cohesion as a guideline. This article illuminates the difficulties flood control project engineers face when working in local communities and argues that engineering issues are also social issues. Further, the relocatees within this flood control project voice some of the same concerns experienced by people relocated in other involuntary infrastructure development projects. The case outlined in this article could be used to better help those involuntarily relocated for flood control.