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Golden Rays – October 2017

The Solar Newsletter is an electronic newsletter that provides information on NREL's research and development of solar technologies.

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Hot Topics

NREL scientist Adele Tamboli, co-author of a recent article on silicon-based multijunction solar cells, stands in front of an array of solar panels.

Multijunction Efficiency Records Crushed

Collaborating with teams at two Swiss research institutions, NREL researchers have set new efficiency records for two- and three-junction tandem solar cells. These cells, which combine common, lower-cost silicon cells with higher-cost, higher-efficiency III-V cells, may offer a possible pathway to more efficient, mass-market PV panels.

The team from NREL, the Swiss Center for Electronics and Microtechnology (CSEM), and the École Polytechnique Fédérale de Lausanne published their findings in Nature Energy. They achieved a 32.8% efficiency for a two-junction tandem cell that stacked a layer of gallium arsenide (GaAs) developed by NREL atop a film of crystalline silicon developed by CSEM. Their three-junction cell, achieving an efficiency of 35.9%—just 2% below the overall triple-junction record—stacked a gallium indium phosphide (GaInP)/GaAs tandem cell stacked on a silicon bottom cell. They also improved on a GaInP-based tandem cell, boosting it to an efficiency of 32.5%. Today's mass-market silicon cells have efficiencies between 17% and 24%.

A lithium ion battery system, owned and operated by NREL for grid integration research at the National Wind Technology Center.

The Power of PV-Plus-Storage

Should batteries sit on the AC- or DC-side of an inverter? What are the benefits of co-locating a battery with a PV array? Despite significant industry discussion, relatively few PV-plus-storage systems have been installed and their performance has not been carefully tracked and compared.

A new NREL report examines the tradeoffs between various PV-plus-storage configurations. Evaluating the Technical and Economic Performance of PV Plus Storage Power Plants fills an important gap in the research by further defining the various utility-scale PV plus storage configurations available to developers. It examines the potential changes in cost and value associated with different configurations and analyzes the impacts of the investment tax credit. The report also demonstrates how energy storage can mitigate the decline in value that PV systems will face as PV penetration increases.

Researcher Judith Gomez-Vidal determined the coatings needed to allow concentrating solar power plants to store and use molten salts.

Next-Gen CSP Requires Next-Gen Corrosion Resistance

Next-generation concentrating solar power (CSP) plants require high-temperature fluids, like molten salts, in the range of 550-750 degrees Celsius to store heat and generate electricity. At those high temperatures, however, the molten salts eat away at common alloys used in CSP systems. New NREL research is aimed at designing new coatings to protect from these high-temperature fluids and ensure slow corrosion rates—less than 20 micrometers per year—so that a next-gen concentrating solar power plant can achieve a 30-year lifespan.

Must Reads


Projects and Partnerships

  • Simulation, Characterization, and Reliability at Next DuraMAT Workshop

    The Durable Module Materials Consortium (DuraMAT) will focus on materials reliability, predicative simulation, and advanced characterization at its next workshop on Nov. 7–8, 2017. Researchers funded by the consortium, as well as invited members of industry, will be presenting at the workshop. Poster sessions and working groups will strengthen relationships within the community, advance progress on current research, and identify new areas of high impact research. Sandia National Laboratories will host the workshop at the Sheraton Albuquerque Uptown. Visit the workshop's Eventbrite page to register to attend.

  • Young PV Scientists Get Hands-On at NREL

    Thirteen graduate students got a once-in-a-lifetime opportunity to learn from top solar scientists during the 2017 Hands-On PV Experience Workshop at NREL. Hailing from eight American research universities, the students received a broad introduction to issues in PV research and dug deeper on topics related to their own research. The annual workshop fosters important ties between NREL and the next generation of PV researchers.

  • Boosting Solar in Low-Income Communities

    Most low-to-moderate income (LMI) communities in the United States do not enjoy the same access to solar power as their wealthier neighbors. To address this disparity, a new, 3-year study by NREL seeks to identify new strategies to dramatically boost solar adoption rates in LMI communities. The NREL study is part of the U.S. Department of Energy's Solar Energy Evolution and Diffusion Studies, a series of industry-wide studies that use data-driven and evidence-based methods to understand barriers to PV adoption. Learn more about the NREL study's cross-disciplinary approach on its newly launched website.

  • Getting India to its Ambitious Renewable Energy Goal

    NREL, working with a broad team of American and Indian organizations, has completed a major study confirming that it is technically and economically feasible for India to meet its goal of integrating 175 gigawatts (GW) of renewable energy by 2022. The international team used advanced weather and power system modeling to answer many questions about how India's electricity grid can manage the variability of 175 GW of renewable energy. India's large coal fleet will provide the flexibility needed to accommodate the variability associated with the 2022 renewable energy target without the need to install new, fast-ramping power plants.

  • VIDEO: New Adhesion Test for PV Materials

    NREL has developed a new adhesion test method for PV modules, aimed at quantifying the adhesion of PV laminate materials, required for modules to remain reliable over decades of deployment. Nick Bosco, an NREL scientist who developed the method with the Dauskardt group at Stanford University, demonstrates the new method in a series of videos on the NREL Learning YouTube channel.


40 Years of Energy Innovation Earn a Public Service Award for NREL

The Alliance to Save Energy (ASE) awarded NREL with its 2017 Charles H. Percy Award for Public Service to honor the laboratory's four decades of leadership in advancing energy efficiency technologies and systems. The recognition marks the second national award bestowed on the laboratory this year. In March, the American Council on Renewable Energy presented NREL with its "Technology Advancement and Industry Impact Award."

In Touch with NREL Solar

Opportunities to Partner

CSP Gen3 Funding Opportunity

The DOE SunShot Initiative announced up to $62 million to support early-stage research in Concentrating Solar Power (CSP) technologies to enable on-demand solar energy. Concept papers are due Oct. 27, 2017.

Funding for Power Electronics Projects

The SunShot Initiative has dedicated up to $20 million to early-stage projects to advance power electronics technologies. Advances in power electronics will help grid operators rapidly detect problems and respond, protect against physical and cyber vulnerabilities, and enable consumers to manage electricity use. Concept papers are due Oct. 12, 2017.

Solar Desalination Funding Opportunity

The SunShot Initiative‘s Solar Desalination funding program will develop novel technologies or concepts using solar thermal energy to assist in creating freshwater from otherwise unusable waters. SunShot expects to make 7-10 awards for a total of $15 million in funding. SunShot will host an informational webinar on Oct. 12, 2017. Concept papers are due on Dec. 4, 2017.


Webinar: NREL Charts the Emergence of Corporate Procurement of Utility-Scale PV

Oct. 9, 2017

Join NREL to discuss new research on corporate procurement of solar. Corporations and other institutions have contracted for more than 2,300 MW of off-site solar. New NREL research examines the benefits, challenges, and outlooks for large-scale off-site solar purchasing in the United States.

2017 International PV Soiling Workshop

Oct. 23-25, 2017
Dubai World Trade Center

NREL is partnering with the Dubai Electricity & Water Authority Research and Development Centre to host a three-day workshop on PV panel soiling. More than 40 speakers will cover topics such as field soiling performance, dust characterization, soil adhesion, automated cleaning, and soiling loss modeling.

DuraMAT Workshop

Nov. 7-8, 2017
Albuquerque, NM

The next DuraMAT workshop will focus on materials reliability, predicative simulation, and advanced characterization and will include presentations on research funded by the consortium as well as invited presentations by industry members.

Did you know?

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At the 44th annual PV Specialists Conference, NREL researchers made major contributions, presenting 119 papers. A majority of the NREL papers were oral presentations, reflecting the high quality of work from NREL researchers, and almost all (98 papers) were collaborations with partners from universities, companies, or other national labs. Learn more about working with NREL!