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As the global population accelerates toward a full earth scenario, food, energy, and water demands will increase dramatically. The first order constraints that face resource generation technologies, such as static land availability, compound into second order challenges such as direct competition for the same land and solar photons. Within the contiguous United States, both agriculture and energy production such as solar have turned to densification schemes to increase yields and power per land area, respectively. These technologies coupled with water generation capabilities or management strategies, remain widely separated in their implementation or experience loss in combination. We propose an Agrivoltaic food and energy coproduction architecture to address these challenges, utilizing an Agrivoltaic Array, on-site micrometeorological condition analyses, on-site experimentally validated ray-tracing and irradiance modeling simulation software, as well as crop physiological stage, ear, and height data. Identification of critical time frames in which the relationship between irradiance and yield is highly significant (p less than 0.00005) enables implementation of ideal anti-tracking during those growth periods and solar tracking during all non-critical periods, collectively called critical-time anti-tracking. This reduces power generation to 13.68% during a six-week ideal anti-tracking time frame compared to solar tracking; still, this translates to 86.71% power generation over a year when compared to solar tracking. The reduction in power offsets yield loss, increasing land productivity. This research proposes a technology for near-neutral coproduction of food and energy leveraging already existing hardware for a viable pathway for widespread solar implementation throughout the contiguous United States. [Display omitted] • Unquantified system relationships limit AgPV implementation. • System algorithms and designs must be characterized and evaluated. • First AgPV study to combine full-field modeling and field data to assess performance. • Integration of harvest cycles improves tracking algorithms to meet shareholder needs. • Prototype met the 88.9 % of minimum viable value for powering each state independently. [ABSTRACT FROM AUTHOR]

Solar electricity generation has been investigated in three different sectors as residential, commercial and industrial. This study aims to forecast the solar electricity generation in 5 years by using statistical analysis and make projection of predictions about what could the solar technology can become in Turkey, using USA data on solar electricity generation since statistical analysis is made by using evaluation of regression analysis for these sectors. The results show that the PV generation for the sectors by years such as distributed solar photovoltaic generation value varies from 10.41 MkW h (1989) to 10,464.61 MkW h (2016) for the residential sector; from 14.72 MkW h (1989) to 7179.62 MkW h (2016) for the commercial sector; and from 3.26 MkW h (1989) to 1822.60 MkW h (2016) for the industrial sector. Additionally, forecast of energy distribution (million kW h) has been carried out that from 12783.96 to 28738.31; from 6524.67 to 8018.74; from 1927.91 to 3435.58 with respect to sectors of residential, commercial and industrial, respectively. These results are obtained with the R2 values (0.968667; 0.932558; 0.716024). Consequently, it would not be wrong to express that the solar energy is no more a novelty, but a necessity with the daily electricity usage. In this study, the novelty lies in study's unique combination of analysing goals with a benchmarking evaluation between USA and Turkey. This is illustrated with the forecasting energy distribution of over 8%, a component usage of at least three equivalent sectors. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of existing financial incentive policies in the U.S. for integrated photovoltaic and battery energy storage (PV-BES) systems. A mathematical model of PV-BES system to evaluate annual energy performance is developed in this paper. Four types of buildings (i.e., hospital, large office, large hotel, and secondary school) located in four different states, which each has their own PV and/or BES incentives, are selected and analyzed. Based on the energy performance data for each building type, the simply payback period (PBP) for the PV-BES system in different locations is calculated according to the local incentive policies. The PBP is chosen as an indicator to evaluate the effectiveness of incentive policies for different locations and building types by comparing it to the PBP for the same PV-BES systems without incentive policies. The reduction of carbon dioxide emission (CDE) due to the PV generation is also investigated since it indicates the potential to reduce the PBP for a further step when a high carbon credit is available. Furthermore, a parametric analysis is conducted to determine the sensitivity and contribution of parameters such as the capacity of the PV-BES system, the capital cost of PV module and the battery storage on the performance of the PV-BES system. Results show that for all the evaluated buildings in California and Hawaii, the existing incentive policy could reduce the PBP effectively below 10 years. However, the PBP for most of the evaluated buildings in New Jersey and New York were high even when both the PV and BES incentive policies were taken into account (approximately from 11 to 29 years). [ABSTRACT FROM AUTHOR]

Solar photovoltaic (PV) systems have the greatest potential to meet the scale of sustainable energy demands, yet large surface areas beyond rooftop areas are required. One source of additional surface area that avoids conflict with food production while scaling with population density is noise barriers, which provide dual use of land area both as noise abatement and energy generation. This paper provides a method to quantify the potential of mass scale deployment of photovoltaic noise barrier (PVNB) systems in a country. Based on a feasibility analysis of the irradiation levels and noise barrier locations, the PV power potential and the energy output for the photovoltaic modules is calculated for specific locations using a tool chain of free GIS software. This method, is then demonstrated with a case study for the state of California and the results are then extrapolated for the entire U.S. The U.S. is an ideal candidate country because noise abatement mandates fall well short of World Health Organizations guidelines and PVNB technology has not been implemented on a wide scale. Using conservative assumptions, the results show that the total PVNB power potential for the U.S. ranges from 7 to 9 GW using only existing noise barriers. According to findings of the paper the installed capacity of the large scale photovoltaic system deployed on noise barriers in a single state is comparable to the installed capacities of the largest solar farms in the U.S. and yet due to the unique mounting of PVNB, such systems provide better land utilization ratios for energy production than conventional solar PV farms. [ABSTRACT FROM AUTHOR]

The U.S. electrical grid, the largest and most complex man-made system in the world, is highly vulnerable to three types of external threats: 1) natural disasters, 2) intentional physical attacks, and 3) cyber-attacks. The technical community has recommended hardening the grid to make it more resilient to attack by using distributed generation and microgrids. Solar photovoltaic (PV) systems are an ideal distributed generation technology to provide power for such microgrids. However, both the deployment velocity and the policy of how to implement such technical solutions have been given far less attention than would be normally considered adequate for a national security risk. To address this threat, this paper reviews the technical and economic viability of utilizing defense contracting for the beginning of a national transition to distributed generation in the U.S. First, the technical scale of electrical demand and the solar PV system necessary is analyzed in detail to meet the first level of strategic importance: the U.S. military. The results found that about 17 GW of PV would be needed to fortify the U.S. military domestically. The current domestic geographic deployment of microgrid installations in the critical U.S. defense infrastructure were reviewed and compared to historical grid failures and existing and planned PV installations to mitigate that risk. The results showed a minimal number of military bases have introduced solar PV systems, leaving large parts of the Department of Defense electrical infrastructure vulnerable to attack. To rectify this situation, the technical skills of the top 20 U.S. defense contractors is reviewed and analyzed for a potential contracting transition to grid fortification. Overall the results indicate that a fortified U.S. military grid made up of PV-powered microgrids is technically feasible, within current contractors skill sets and economically viable. Policy recommendations are made to accelerate U.S. military grid fortification. [ABSTRACT FROM AUTHOR]

A source of large surface areas for solar photovoltaic (PV) farms that has been largely overlooked in the 13,000 United States of America (U.S.) airports. This paper hopes to enable PV deployments in most airports by providing an approach to overcome the three primary challenges identified by the Federal Aviation Administration (FAA): (1) reflectivity and glare; (2) radar interference; and (3) physical penetration of airspace. First, these challenges and precautions that must be adhered to for safe PV projects deployment at airports are reviewed and summarized. Since one of the core concerns for PV and airport symbiosis is solar panel reflectivity, and because this data is largely estimated, a controlled experiment is conducted to determine worst-case values of front panel surface reflectivity and compare them to theoretical calculations. Then a general approach to implement solar PV systems in an airport is outlined and this approach is applied to a case study airport. The available land was found to be over 570 acres, which would generate more than 39,000% of the actual annual power demand of the existing airport. The results are discussed while considering the scaling potential of airport-based PV systems throughout the U.S. [ABSTRACT FROM AUTHOR]

The United States may produce as much as 45% of its electricity using solar energy technology by 2050, which could require more than 40,000 km 2 of land to be converted to large-scale solar energy production facilities. Little is known about how such development may impact animal movement. Here, we use five spatially explicit projections of solar energy development through 2050 to assess the extent to which ground-mounted photovoltaic solar energy expansion in the continental United States may impact land-cover and alter areas important for animal movement. Our results suggest that there could be a substantial overlap between solar energy development and land important for animal movement: across projections, 7-17% of total development is expected to occur on land with high value for movement between large protected areas, while 27-33% of total development is expected to occur on land with high value for climate-change-induced migration. We also found substantial variation in the potential overlap of development and land important for movement at the state level. Solar energy development, and the policies that shape it, may align goals for biodiversity and climate change by incorporating the preservation of animal movement as a consideration in the planning process.

The average American is highly supportive of solar photovoltaic (PV) technology and has the opportunity to earn a high return of investment from a PV investment for their own home. Unfortunately, the average American does not have easy access to capital/financing to install a PV system able to meet their aggregate annual electric needs. One method to overcome this challenge is to allow ‘plug-and-play solar’, which is defined as a fully inclusive, commercial, off-the-shelf PV system (normally consisting of a PV module and microinverter), which a prosumer can install by plugging it into an electric outlet and avoiding the need for significant permitting, inspection and interconnection processes. Many advanced countries already allow plug-and-play solar, yet U.S. regulations have lagged behind. In order to assist the U.S. overcome regulatory obstructions to greater PV penetration, this article first reviews the relevant codes and standards from the National Electric Code, local jurisdictions and utilities for PV with a specific focus on plug-and-play solar. Next, commercially available microinverters and alternating current (AC) modules are reviewed for their technical and safety compliance to these standards and all were found to be compliant. The technical requirements are then compared to regulatory and utility requirements using case studies in Michigan, which were found to create arbitrary non-technically-valid barriers to grid entry. The analysis also exposed the redundancy of the utility accessed AC disconnect switch for residential and small commercial grid connected solar PV. It is clear that the AC disconnect switch is not necessary technically and thus imposing it is an economic barrier to grid entry for solar PV systems with UL (Underwriters Laboratories) certified microinverters. To reduce consumer and utility workload and the concomitant soft costs, this article provides a streamlined application with only technical requirements and free and open source software to ease utility implementation. Finally, the advantages of supporting plug-and-play solar PV with UL certified microinverters include greater PV system performance, faster uptake and higher PV penetration levels, improved prosumer economics, and more environmentally responsible electric generation. [ABSTRACT FROM AUTHOR]

The economics in the U.S. of solar photovoltaic (PV) systems is changing rapidly as the cost per unit power of PV modules has dropped quickly. These costs reductions have two important results: marked decrease in levelized cost of electricity (LCOE) into ranges competitive or better than traditional electricity-generation technologies and the economic role of racking has been gaining prominence relative to that of modules. As the relative importance of costs of PV racking has been marginal historically, there has been relatively little progress on reducing the materials and costs associated with it, which has caused racking to contribute to a significant portion of costs of entire PV systems. In order to overcome this challenge this study investigates a novel low-weight PV racking system for commercial rooftops based on crossed cables (X-wires) and compares it to racking systems already available on the market on capital costs, labor costs for installation, and technical specifications such as adaptability and power packing factor. The results of over 80% cost reduction and 33% increase in power density are presented and conclusions are drawn about the potential for tension-based racking systems to further reduce total PV systems costs on commercial flat roof tops resulting in LCOE savings of $0.01–$0.02/kW h. [ABSTRACT FROM AUTHOR]

The number of US photovoltaic (PV) systems has grown rapidly in recent years, driven by a wide array of government incentives and other supportive policies aimed, in part, at reducing PV system prices. This article draws from a sample of more than 200,000 US residential, commercial, and utility-scale PV projects to summarize price trends for PV systems installed from 1998 through 2012. These data show that the average installed price of US residential and commercial PV systems declined 6-7% annually during 1998-2012, although the pace and source of price reductions varied. In 2012, the median reported installed price of residential and commercial PV systems was $5.3/W for systems of 10 kW or smaller, $4.9/W for systems of 10-100 kW, and $4.6/W for systems larger than 100 kW. The capacity-weighted average installed price of crystalline, fixed-tilt, utility-scale PV systems (ground-mounted systems at least 2 MW in size) declined from $6.2/W during 2007-2009 to $3.3/W in 2012. Recent price reductions are associated primarily with a precipitous drop in PV module prices, while non-module costs have remained relatively stagnant since 2005. Further system price reductions will be needed to expand US PV deployment as incentive programs reduce their financial support. Because further module price reductions are limited, additional deep reductions in installed prices will require significant reductions in non-module costs, particularly non-hardware ('soft') costs. Lower installed prices in international markets suggest that deep near-term soft cost reductions in the USA are possible with the help of targeted policies. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article presents a study that investigates the effectiveness of graphene flexographic printing as replacement of platinum in counteracting catalyst electrodes in the U.S. The methods used by researchers to find replacement of platinum assembly. Moreover, the potential of graphene nanoplatelet (GNP) are stated.

Cupric oxide thin films were deposited onto soda lime glass by spin coating and subsequent annealing of copper nitrate dissolved in a glycerol–water solvent. It was found that the solution consistently gave reproducible films with good adhesion on glass. A range of band gaps were estimated between 0·8 and 1·17 eV, showing that this material has potential as a photoabsorber. Resistivity was successfully reduced from 1·47×105 to 7·02 Ω cm by doping the films with sodium. Dopant concentrations of 1 at-% gave the lowest resistivity, showing that the ideal doping is 1% or less. Film structure was found to improve with an increase in annealing time from 10 min to 1 h, although this did not have any noticeable effect on either the electrical or optical properties of the films. [ABSTRACT FROM AUTHOR]

Highlights: [•] Several airports have recently installed photovoltaic arrays on their properties. [•] We studied bird use of photovoltaic arrays and airport grasslands in three states. [•] Overall photovoltaic arrays did not increase bird hazards to aviation at airports. [•] Large species hazardous to aviation were less abundant on photovoltaic arrays. [Copyright &y& Elsevier]

Abstract: Consumer perception could play an important role in the adoption of renewable energy technologies. This study aims to explore the role of consumer acceptance and model its effect on residential photovoltaic (PV) adoption. A survey was conducted to understand consumer perceptions of the technology (perception variables), such as perceived cost, perceived maintenance requirement, and environmental concern. To further investigate the adoption potential of residential PV, this paper develops a fuzzy logic inference model to relate consumer perception variables (inputs to the model) to their purchasing probability (output from the model). This model is tested in a case study of residential PV adoption using data from a survey of homeowners in Arizona, United States. The quantitative results of the model demonstrate the role of each perception variable in the consumer acceptance of PV. Public has tended to emphasize on the role of cost reduction in promoting the adoption of residential PV. The results of this study show that other issues such as maintenance requirement and environmental concern are also important. [Copyright &y& Elsevier]

Abstract: Optimum tilt and azimuth angles for solar panels were calculated for a grid of 0.1° by 0.1° National Solar Radiation Database (NSRDB-SUNY) cells covering the continental United States. Optimum tilt and azimuth angles varied by up to 10° from the rule of thumb of latitude tilt and due south azimuth, especially in coastal areas, Florida, Texas, New Mexico, and Colorado. The yearly global irradiation incident on a panel at this optimum orientation was compared to the solar radiation received by a flat horizontal panel and a 2-axis tracking panel. Compared to global horizontal irradiation, irradiation at optimum fixed tilt increased with increasing latitude and by 10%–25% per year. Irradiation incident on a 2-axis tracking panel in one year was 25%–45% higher than irradiation received by a panel at optimum fixed orientation. The highest increases in tracking irradiation were seen in the southwestern states, where irradiation was already large, leading to annual irradiation of over 3.4MWhm−2. [Copyright &y& Elsevier]

Abstract: In this paper, Radial Basis Function network (RBF) is used for modelling and predicting the daily global solar radiation data using other meteorological data such as air temperature, sunshine duration, and relative humidity. These data were recorded in the period 1998–2002 at Al-Madinah (Saudi Arabia) by the National Renewable Energy Laboratory. Four RBF-models have been developed for predicting the daily global solar radiation. It was found that the RBF-model which uses the sunshine duration and air temperature as input parameters, gives accurate results as the correlation coefficient in this case is 98.80%. A comparative study between developed RBF, Multilayer perceptron and conventional regression models are presented and discussed in this paper, In addition, an application for estimating the sizing of a stand-alone PV system at Al-Maidinah is presented in order to show the effectiveness of the developed RBF-model. [ABSTRACT FROM AUTHOR]

Abstract: The historically high cost of crude oil price is stimulating research into solar (green) energy as an alternative energy source. In general, applications with large solar energy output require a maximum power point tracking (MPPT) algorithm to optimize the power generated by the photovoltaic effect. This work aims to provide a stand-alone solution for solar energy applications by integrating a DC/DC buck converter to a newly developed quadratic MPPT algorithm along with its appropriate software and hardware. The quadratic MPPT method utilizes three previously used duty cycles with their corresponding power outputs. It approaches the maximum value by using a second order polynomial formula, which converges faster than the existing MPPT algorithm. The hardware implementation takes advantage of the real-time controller system from National Instruments, USA. Experimental results have shown that the proposed solar mechatronics system can correctly and effectively track the maximum power point without any difficulties. [Copyright &y& Elsevier]

Abstract: This paper reports a design and building process of a net-zero-energy modular house, named ElementHouse, which was entered for the 2007 Solar Decathlon competition that was organized by the U.S. Department of Energy. This paper discusses the development of the ElementHouse from its initial concept to the actual construction, which integrated multi-disciplinary knowledge of architecture, mechanical engineering, and electrical engineering. By employing computer-aided simulation tools, several design approaches were developed to achieve the optimal balance among function, aesthetics, economy, and energy—a challenge in many sustainable building designs. A simplified energy model helped to form the building configuration at the preliminary design stage by showing how energy use is affected by various parameters, leading to optimization studies that provided design guidelines towards an energy-efficient building envelope and opening design. Energy modelling also estimated the annual energy use and electricity generation, as well as the costs associated with long-term operation of the house. The energy demand estimate and its daily power profile helped to design the photovoltaic (PV) system. The modular configuration of the building and its roof structure was then iteratively altered to accommodate the PV panels in such a way as to generate the most power and to facilitate interstate transportation of ElementHouse. With the progress of the design process, detailed energy simulation using EnergyPlus provided more accurate estimates of power use and generation and, coupled with daylighting simulation performed with Radiance, permitted finalizing the building envelope, opening, and electric lighting design. The building envelope embraced the passive and low energy philosophy to minimize the annual heating and cooling load and to optimize natural lighting. By illustrating the whole picture of ElementHouse design, this paper discusses a way of effectively designing and building a comfortable and affordable solar house. [Copyright &y& Elsevier]

Abstract: The recent development of small scale combined heat and power (CHP) systems has provided the opportunity for in-house power backup of residential-scale photovoltaic (PV) arrays. This paper investigates the potential of deploying a distributed network of PV+CHP hybrid systems in order to increase the PV penetration level in the U.S. The temporal distribution of solar flux, electrical and heating requirements for representative U.S. single family residences were analyzed and the results clearly show that hybridizing CHP with PV can enable additional PV deployment above what is possible with a conventional centralized electric generation system. The technical evolution of such PV+CHP hybrid systems was developed from the present (near market) technology through four generations, which enable high utilization rates of both PV-generated electricity and CHP-generated heat. A method to determine the maximum percent of PV-generated electricity on the grid without energy storage was derived and applied to an example area. The results show that a PV+CHP hybrid system not only has the potential to radically reduce energy waste in the status quo electrical and heating systems, but it also enables the share of solar PV to be expanded by about a factor of five. [Copyright &y& Elsevier]

Abstract: Photovoltaics and renewable energies are growing at a much faster pace than the rest of the economy in Europe and worldwide. This and the dramatic oil price increases in 2005 have led to a remarkable re-evaluation of the renewable energy sector by politics and financing institutions. Despite the fact that there are still discrepancies between the European Union and the USA, as to how to deal with climate change, renewable energies will play an important role for the implementation of the Kyoto Protocol and the worldwide introduction of tradable Green Certificates. Apart from the electricity sector, renewable energy sources for the generation of heat and the use of environment friendly biofuels for the transport sector will become more and more important in the future. [Copyright &y& Elsevier]

Although wealth inequality has many established negatives, this study investigates a potential positive, unprecedented wealth concentration makes it possible for solutions to large and seemingly intractable problems to be deployed by convincing a relatively small number of individuals to invest. In order to probe this potential outcome of inequality, this study quantifies the number of people necessary to radically reduce the greenhouse gas emissions responsible for global climate destabilization from the U.S. electric grid, which is one of the largest sources of emissions. Specifically, this study determined that 1544 GW of solar photovoltaic (PV) technology must be deployed to eliminate the use of fossil fuels on the U.S. electric grid, if PV is conservatively deployed as a function of population density. The results showed that only 79 American multi-billionaires would need to invest in PV. This investment would still leave each investor with a billion dollars of liquid assets as well as substantial long-term profits from PV. The analysis also concluded that 79 people is a conservative upper estimate of those that would need to be convinced of the usefulness of moving to a solar U.S. grid and that this estimate is likely to decrease further in the future. [ABSTRACT FROM AUTHOR]