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Graduate Student Research Shines at the Solar Nexus Annual Meeting

Graduate Students 2017 Solar Nexus Annual Meeting
Graduate Students at the 2017 Solar Nexus Annual Meeting
–L. Brazfield Photo

Graduate Student Research Shines at the Solar Nexus Annual Meeting

Students display their highly relevant research for the interdisciplinary NEXUS project at the meeting’s poster session

By Jane Palmer
April, 2017

Behind every good research project lays a talented graduate student and at the 2017 Solar Nexus annual meeting, 47 graduate students convened to display their research contributions to the interdisciplinary NEXUS project during the meeting’s poster session.
The students’ research serves to support and advance Solar Nexus’ mission, as their projects aim to increase solar energy efficiency and investigate the impacts of utility solar energy plants on the environment and water resources. Students are also investigating the creation of a secure cyberinfrastructure to support data sharing and processing and are analyzing the economics of different styles of solar energy production.
“The 47 graduate students empowered by the Solar Nexus project are the underlying engines that inspire and innovate our research,” says Dr. Gayle Dana, Project Director.  “They are the stars of the science here.”
In supporting these students, the NEXUS program is not only facilitating scientific research in key research areas for Nevada, but it is also contributing to workforce development in the state.
A few highlights from the poster session are below. To view the all the student poster abstracts please click here.

Lorenzo Apodaca

Investigating the Impacts of Utility-Scale Photovoltaic Panel Facilities on Nearby Vegetation  

As demand for clean and sustainable energy has continued to grow, large-scale photovoltaic (PV) panel facilities have cropped up in recent years throughout Nevada but the impact of such facilities on the local environment is still an unknown. To address this issue graduate student Lorenzo Apodaca from the University of Nevada Las Vegas (UNLV) and his supervisor Dr. Dale Devitt have been investigating the ecological impacts of the Copper Mountain 2 (CM2) solar facility in Eldorado Valley, Nevada. This facility uses nearly 1.8 square kilometers of photovoltaic panels to generate enough energy to power about 50,000 homes and it is surrounded by mainly creosote and white bursage vegetation. The scientists are investigating both the impacts of the panel arrays on the microclimate and the surface hydrology surrounding the arrays. So far, the team has found that overnight air temperatures near to the facility are higher than those further away with the largest heating effect occurring during the cooler months.  Higher temperatures can be detrimental to overall water availability and increase plant water stress, but the specific effects of increased heat on the study plants is not yet clear. By monitoring the individual creosote and bursage plants, the team have found, however, that the creosote plants growing closest to CM2 are under greater water stress than plants growing further away. “Solar energy is still emerging as a competitor in the energy market so we still have the opportunity to confront any issues early, but that requires solid research on possible effects,” Apodaca says. “I think a clearer picture of the environmental impacts of solar energy farms will come from this study and this could lead to more environmentally-conscious ways to zone for and construct these facilities.”

Using Nanotechnology, Not Water, to Clean Solar Panels

When dust, or airborne particles coat solar panels, the coating can affect the panels’ ability to absorb sunlight and drastically reduce the conversion of the Sun’s rays into energy. This has made it necessary to periodically wash the panels with water but, often, in areas like Nevada where solar energy production is prolific, water resources are scarce. Consequently, some scientists have turned their attention toward developing technologies for waterless cleaning but many of these techniques are expensive and not cost effective for large-scale PV power generation. To attempt to develop a water-free cleaning technology that will be cost-effective for large-scale PV generation, NEXUS graduate student Sanjana Das from UNLV and her supervisor Dr. Biswajit Das, have turned their attention to a potential nanotechnology solution. The technology involves the use of arrays of transparent nanoparticles deposited on the solar panels. The nanostructure arrays provide a focused electric field to modify the electrical properties of the dust particles. Once these particles are charged, they can be removed by electrostatic sweeping, a process whereby nanoparticles generate an electric field to collect the dust at intervals. “This project will enable a maintenance free, clean solar panel surface during the operational life of the panels, thereby maintaining steady power output efficiency while eliminating the inefficient and water consuming cleaning operation,” Das says.

Esra Erdin App

Developing a Secure Social Network App for Mobile Devices

Social networking has allowed billions of people to interact and share information with friends and family, but it has also allowed online platforms to amass user data, causing concern for individual’s privacy. Systems that remove a central authority but allow data sharing directly between individuals may be one solution to this problem. Such “decentralized cyber-architectures” do have a performance cost in terms of efficient data sharing and timely access of objects, however. To address these performance issues NEXUS graduate student Esra Erdin at the University of Nevada Reno (UNR) and her supervisor Dr. Mehmet Gunes are investigating the use of free storage clouds to distribute encrypted user content between individuals. The researchers have developed a POSN app that uses these clouds and allows the user to have control of the shared content. This architecture protects personal data from being accessed by third parties. “We hope that this will help individuals have a future safe Internet experience,” Erdin says.

Measuring Public Attitudes Towards Residential Rooftop Solar Policies

Recent changes to net metering policies in several states, including Nevada, have initiated mixed reactions in the public and policy makers. Under the older policies people with rooftop solar effectively underpaid for their use of the grid network, so the utilities have raised the price of using the grid for all users and in doing so, have unfairly targeted lower income users. Such changes in terms of who pays for grid use is known as “cost shifting.” The new policies, however, have greater impacts on the solar-panel users and have reduced their compensation for generation to the grid to near zero, causing many owners to lose money on their solar investment. Rooftop owners have widely protested the new policies but the general public’s opinion is still relatively unknown.

Consequently, NEXUS graduate student Brian Fogarty and NEXUS economists Dr. Dilek Uz, and Dr. Thomas Harris at UNR are conducting a public opinion survey to help fill the void of knowledge that currently exists regarding the public’s views towards the new policies. The survey will help complement results from ongoing research on the net metering information, advanced metering infrastructure, solar energy potential, electricity prices, and electricity intensity for each state.
“At this time we don’t know if the public is aware of the cost shifting idea, or if they are aware but believe the benefits of solar power outweigh the costs,” Fogarty says. “This survey aims to fill this gap in knowledge.”

Improving Solar Forecasting for Increased Solar Energy Efficiency

Sunlight is a good source of energy but variable cloud cover can make the energy levels produced by power plants fluctuate. Consequently, to economically integrate substantial amounts of solar power into their power generation portfolios, power companies need accurate forecasts of how much sun will reach panels on a daily basis. By knowing these numbers, grid operators can anticipate the fluctuations from solar energy sources and make the necessary accommodations.

In the southern Nevada region, monsoon-related events can cause local cloudiness in the summertime. The numerical weather prediction (NWP)-based global horizontal irradiance (GHI), and clear-sky index forecasts provide accurate forecasts, except when the weather is changing quickly, from cloudy to clear, or vice versa. NEXUS graduate student Marco Giordano, along with NEXUS scientists Drs. John Mejia and Eric Wilcox from the Desert Research Institute have studied the ability of these models to deliver accurate day-ahead forecasts at a site in Las Vegas. Their analysis has revealed how possible modifications will improve forecasts for some of the transitional days that are North American Monsoon related. “Rapid changes in the presence and extent of cloud cover complicate the time scales relevant for solar forecasting,” Giordano says, “So our goal is to discover physics-based computational strategies that will help provide more accurate day-ahead forecasts for power companies.”

Surfactant Effects on Direct Contact Membrane Distillation

Using direct contact membrane distillation (DCMD) has already proved effective for treating on-site groundwater to produce high-quality water for solar panel or mirror cleaning. The technology uses a membrane with small pores in it that allows water vapor transport, but rejects contaminants such as salts and minerals. One of the main advantages of DCMD is that the process can utilize waste heat or solar energy.

Sometimes, however, the cleaning materials and soaps used to clean the panels-termed surfactants-can interfere with the membrane’s ability to transform the groundwater into the higher-quality water. To test out at what concentration individual surfactants caused a problem for DCMD, NEXUS graduate student, Coral Taylor, and her supervisor Dr. Sage Hiibel at UNR, have run tests on different membranes using a common surfactant at varying concentrations. Their findings can provide guidance for developing panel or mirror washing protocols at solar sites. The results will also inform future membrane development in terms of expanding DCMD applicability to a broader range of waters requiring treatment, such as grey water and wastewater. “In arid locations, we need to minimize water use and re-use water as much as possible,” Taylor says. “Membrane distillation can be used to treat re-used water, and thereby assist in water conservation efforts.”
Science Communication Graduate Student Workshop March 2017
Science Communication Graduate Student
Workshop –M. Casella Photo

Learning To Be An Advocate For Science

The NEXUS project aims to push the boundaries of research at the solar energy-water-environment nexus but it also recognizes that an important mission of any scientific program is to communicate its findings beyond the scientific community.
As part of this mission, the NEXUS program provided a one-day workshop on “Communicating Your Science” to its graduate students at its annual 2017 meeting. During this day, the students learned the fundamentals of communicating their research message and how to communicate their science to the media. The students also learned to craft a 30-second elevator speech-a short speech that could be delivered to a member of the public during a typical elevator ride. They discovered how to distill their message into clear and accessible sound bites for the layperson and deliver their speech with energy and enthusiasm.

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Nexus Notes monthly publication
April 2017

NEXUS Notes is a monthly publication of the Solar Nexus Project, which is a five-year research project funded by the National Science Foundation’s Experimental Program to Stimulate Competitive Research “EPSCoR” (Cooperative Agreement #IIA-1301726) focusing on the nexus of (or linkage between) solar energy generation and Nevada’s limited water resources and fragile environment.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

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If you would like to know more about the NEXUS project,
please contact, Dr. Gayle Dana
Gayle.Dana@dri.edu
530-414-3170

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