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Golden Rays — June 2017
A global PV capacity of 5–10 terawatts could be installed by 2030, according to a recent Science paper authored by researchers from the Global Alliance for Solar Energy Research Institutes (GA-SERI). The paper presents a realistic pathway to realizing terawatt-scale PV and identifies key steps, including:
- A continued reduction in the cost of PV and improvement in performance
- Expansions to manufacturing and installation capacity
- More flexible grids that can handle high levels of PV deployment
- An increase in demand for electricity by using more for transportation and heating or cooling
- Continued progress in energy storage.
The paper's authors include researchers from NREL, the Fraunhofer Institute for Solar Energy in Germany, and the National Institute of Advanced Industrial Science and Technology in Japan. The paper grew out of a March 2016 gathering in Germany of the GA-SERI.
In 2016, NREL completed the landmark Eastern Renewable Generation Integration Study (seen in the video above), modeling the entire Eastern Interconnect and demonstrating that the system responsible for powering most of eastern Canada and the eastern United States can accommodate upwards of 30% wind and solar power.
Now, NREL researchers have set their sights on an even bigger target: modeling the entire North American power system. NREL's North American Renewable Integration Study (NARIS) will analyze potential pathways to modernize the North American power system through the efficient planning of transmission, generation, and demand. As power from wind, solar, hydropower, and natural gas continues to increase, NARIS will illuminate possible power system futures and explore how the United States, Canada, and Mexico can collaborate to enable economic competitiveness and reliability.
Collaborating with partners in Canada and Mexico, NREL will model and compare various geographic resource diversity scenarios to determine how North America could most effectively use all its renewable resources to reach 50% renewable power by 2025. Currently, 38% of the continent's electricity comes from renewable resources. The study will also attempt to quantify the costs and benefits of pursuing different collaborative North American grid operation trajectories, including environmental impacts, fuel cost savings, and deferred capital investments. Final results of the study are expected in 2019.
On May 3, NREL's Technology Transfer Office recognized the scientists and engineers behind its innovation and partnering successes at the lab's annual Innovation and Technology Transfer Awards ceremony. Many staff members were recognized for their solar-related work.
In fiscal year 2016, NREL had 118 active collaborative research and development agreements. (Traditionally, NREL holds more of these agreements than any other national laboratory.) Overall, 259 new partnership agreements were signed in FY 2016, boosting the lab's number of total active partnerships to 749. Also in FY 2016, the lab filed a record-breaking 173 invention submissions and 107 new patent applications—all while closing 38 intellectual property agreements and maintaining a total of 239 active issued U.S. patents and 68 active issued foreign patents.
Projects and Partnerships
For more than 20 years, the Industry Growth Forum (IGF) has been the nation's premier clean-energy investment event. IGF brings together key clean-energy stakeholders, investors, and 30 carefully selected startups, for an opportunity to network and find avenues for generating new investments and revenue. This year, the Forum was buzzing with news of a $20 million expansion to the Wells Fargo Innovation Incubator. That program, funded by the Wells Fargo Foundation and managed by NREL, facilitates early-stage technologies that provide scalable solutions in sectors such as buildings, transportation, sustainable agriculture, and energy storage.
Although trends at IGF have changed over time—solar pricing models were new 10 years ago, whereas big data and offshore wind are emerging today—the IGF remains one the best opportunities for investors and entrepreneurs to connect and jumpstart the next big innovation in clean energy.
A team of NREL researchers has set a record efficiency for a dual-junction solar cell, surpassing the previous mark by a full percentage point. Under one sun of illumination, the new cell's efficiency was certified at 32.6%.
The series-connected device comprises a 1.7-eV GaInAsP top cell and a lattice-mismatched, 1.1-eV GaInAs bottom cell, grown monolithically by atmospheric pressure metal-organic vapor-phase epitaxy. This technique is compatible with substrate removal and reuse technologies, which are important for reducing costs and realizing lightweight and flexible solar cells. The NREL team developed this tandem solar cell as part of a larger ongoing project to design a six-junction concentrator solar cell with a target efficiency of >50% at high illumination intensity.
For the past year, First Solar, NREL, and the California grid operator CAISO have been testing the capabilities of a 300-megawatt solar farm in the Mojave Desert to provide grid frequency regulation, voltage control, and other valuable grid-balancing tasks.
The solar farm is not storing and shifting its energy to different hours of the day. But it is sometimes running below its full capacity, providing headroom to shift up or down along with CAISO wholesale market prices. Its inverters can also manage the voltage fluctuations caused by passing clouds. Significantly, the plant is capable of responding to CAISO's frequency-regulation signals at a speed that exceeds natural-gas-fired power plants.
In the future, NREL and First Solar hope to demonstrate the "synthetic inertia" capability of utility-scale photovoltaics. The latest developments in power electronics and software controls are allowing inverters to be orchestrated in a way that mimics the inertia of large, spinning power plants.
Mike Wagner, an NREL engineer and Colorado School of Mines Ph.D. student, won the Dr. Bhakta Rath and Sushama Rath Research Award, awarded by Mines for dissertations that demonstrate the greatest potential for societal impact.
Wagner's dissertation presents a model for optimizing the dispatch of energy generated from concentrating solar power (CSP) systems. Normally, after sunset, these systems run their turbines continuously until their thermal reserve is depleted. Wagner created software that determines a dispatch strategy over 24 hours, considering factors such as system configuration, storage tank size, production capacities, and ramp rates. He applied this model to the Crescent Dunes CSP plant in Tonopah, Nevada.
Wagner, who joined NREL in 2009 as a mechanical engineer in the Thermal Systems Group, worked full-time while pursuing his Ph.D.
In Touch with NREL Solar
June 25–30, 2017, Washington, DC
June 26–27, 2017, Hershey, PA
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