Energy Systems Integration Newsletter: May 2021

In this edition, exploring the challenges on the way to a 100% renewable electric grid, a look at the future potential of energy storage, NREL researchers launch an open-source visualization tool to improve forecasting for variable renewable energy resources, and more!

Solar panels and wind turbines in a grassy field with a cityscape in the background.

What We Know—and Do Not Know—about Achieving a National-Scale 100% Renewable Electric Grid

We have growing confidence that reliable, 100% renewable electric grids are technically feasible. But expanding this end goal across the entire United States presents an equally expansive set of challenges—as fervently debated among the energy research community in recent years.

Now, a team of 17 power systems experts from NREL and the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy is chiming in with a fresh take.

Published in the journal Joule, “The Challenges of Achieving a 100% Renewable Electricity System in the United States” offers important insights into the technical and economic challenges that would need to be overcome to achieve 100% renewable electric power across the United States.

Read more about the technical and economic challenges that would need to be overcome to achieve 100% renewable electric power.

Storage Futures Study Finds U.S. Storage Capacity Could Increase Fivefold by 2050

The latest report from NREL’s Storage Futures Study, outlining the economic potential of utility-scale diurnal (up to 12 hours) energy storage in the United States, projects 125 GW of storage capacity by 2050. Today, there are 23 GW of installed storage capacity on the U.S. power system.

“These are game-changing numbers,” said Will Frazier, NREL senior analyst and principal investigator of the study. Learn what factors drive future storage deployment to realize its full market potential (hint: system flexibility and solar photovoltaics). 

New Open-Source Visualization Tool Integrates Advanced Forecasting for Variable Renewables

To help operational control centers and utility forecasting teams develop situational awareness and timely mitigation strategies, NREL researchers have released the Resource Forecast and Ramp Visualization for Situational Awareness (RAVIS) tool. RAVIS is an open-source visualization tool that provides users a way to integrate advanced forecasts for variable renewables, including probabilistic forecasts. Funded by DOE's Solar Energy Technologies Office, the toll can alert users to significant up or down ramps for both individual variable renewable sites as well as regionally aggregated net load ramps, and alerts can also be qualified with respect to available flexible generation.

The modular dashboard of RAVIS contains configurable panes for viewing probabilistic time-series renewable forecasts; ramp event alerts; spatially resolved resource sites and forecasts; and system simulation and market clearing data, such as transmission line utilization, nodal prices, and available generation flexibility.

The team behind RAVIS, led by NREL researcher Venkat Krishnan, recently released a technical report detailing the tool as well as an online demo for users to test several features outlined in the report.

NREL Researchers Take a Practical Look beyond Short-Term Energy Storage

With variable renewable energy expected to become a much larger share of the global energy mix, storage solutions are needed beyond short-duration timescales, such as standard commercial batteries, which are suitable for covering hourly differences in net load.

An article in Nature Energy “News & Views” by NREL research engineer Omar J. Guerra describes research needs for longer-duration and seasonal energy storage solutions. The article, titled “Beyond Short-Duration Energy Storage,” reviews important practical implications of a research article contributed by Nestor A. Sepulveda and colleagues as well as research opportunities to develop a stronger understanding of how long-term and seasonal storage technologies can become cost-effective and grid-supportive energy solutions.

Learn how improved research can advance energy storage.

Flexible Loads and Renewable Energy Work Together in a Highly Electrified Future

Demand flexibility is key to supporting a highly electrified, renewables-based U.S. power system, says the sixth and final report in NREL's Electrification Futures Study, Operational Analysis of U.S. Power Systems with Increased Electrification and Demand-Side Flexibility.

“Flexible loads—primarily from optimized vehicle charging and flexible operations of end-use equipment in buildings and industry—can help support variable renewable energy to meet new electrified demands,” said Ella Zhou, NREL analyst and lead author of the paper. “In turn, this combination of high electrification and high renewable energy can drive significant carbon emissions reductions.” Learn more about the final phase of the Electrification Futures Study, and join a free NREL webinar on Thursday, June 17.

NREL Analysis Reveals the Curtailment Paradox

Curtailment—the reduction of renewable energy delivered because of oversupply or lack of system flexibility—will likely be the new normal in the evolving grid, but it is important to find the optimal level that captures the most value from variable renewable energy resources. NREL analysts studied how individual flexibility options impact curtailment in high variable renewable energy futures, which has not been well understood. The study revealed a counterintuitive relationship between flexibility options and curtailment with high solar deployment, dubbed the “curtailment paradox.” Read the full story, and join a free NREL webinar on Thursday, June 24, to learn more. Register to attend.

Battery-Wind Integration Research Considered for Best Paper

An NREL article describing the DC connection of battery storage and wind power was selected for the best paper session at the 2021 IEEE Power and Energy Society General Meeting. The paper “Integration of Storage in the DC Link of a Full Converter-Based Distributed Wind Turbine” describes NREL's modeling and analysis of a battery energy storage system integrated with a Type IV wind turbine through a DC link. A battery system integrated in this way could be used to perform various control functions and grid services, including improved power output quality, dispatch for forecasted power demand, and black start in the case of power loss. IEEE will announce the winner in July.

*This story has been corrected. The story previously reported that the paper had already been announced as a winner for Best Paper.

Launch of New Power Systems Consortium Signals Commitment to Decarbonization

During a recent launch event of the Global Power System Transformation Con (G-PST) Consortium, system operator CEOs and energy leaders from around the world discussed paths to net-zero emissions. The new undertaking is meant to contribute to slashing emissions from the power sector by at least 50% during the next 10 years. Members of the G-PST Consortium will work to enable high levels of renewable energy grid integration while improving grid reliability, resilience, and security.

Read more about the consortium, including comments from Secretary of Energy Jennifer Granholm, who participated in the launch event.

Energy Systems Integration Facility Lauded in Recent International Organization for Standardization Audit

A recent International Organization for Standardization surveillance audit for continued certification commended the Energy Systems Integration Facility (ESIF), finding no opportunities for improvement and no items of nonconformity. The ESIF was specifically commended for its customer feedback strengths, including the collection of feedback and the actions taken in response. The results of the audit affirm the facility's commitment to its stakeholders and validate its best-in-class facility mission.

Publications Roundup

Optimality Versus Reality: Closing the Gap Between Renewable Energy Decision Models and Government Deployment in the United States

Energy decision models are widely used to evaluate the technical and economic feasibility of renewable energy; however, the optimal model is often different from what is actually deployed. To help increase clean energy deployment and inform clean energy policy, regulation, planning, and deployment, NREL researchers detail why discrepancies exist between the models and actual deployments in the public sector. In this paper published in Energy Research & Social Science, researchers used the results of 20 federal, state, and city government agencies that have used NREL's REopt™ (Renewable Energy Integration and Optimization) tool to inform energy decisions to build a proposal for adaptations to technical modeling capabilities.

Electrifying Transit: A Guidebook for Implementing Battery Electric Buses

As more cities seek to reduce emissions and traffic congestion, battery electric bus (BEBs) fleets are becoming more attractive options. Although BEBs can provide benefits such as reduced fuel and maintenance costs, improved performance, reduced emissions, and increased energy security, a number of challenges still face BEB deployment, including up-front cost premiums and unfamiliarity with BEB technology. To help stakeholders who are interested in deploying BEBs, this guidebook, developed through the NREL-U.S. Agency for International Development partnership, describes the decisions and considerations required for successful BEB implementation.

Power Sector Cybersecurity Building Blocks

To help organizations develop a robust cybersecurity defense program, NREL researchers have developed this guide on power sector cybersecurity. Developed though the U.S. Agency for International Development-NREL partnership's Resilient Energy Platform, these building blocks are designed to help a variety of stakeholders improve security for the electric grid. The document outlines 11 building blocks that organizations can use to effectively prioritize their cybersecurity efforts to prevent a wide range of potential cyberattacks.

Benefits and Critical Knowledge Gaps in Determining the Role of Floating Photovoltaics in the Energy-Water-Food-Nexus

Floating solar photovoltaic systems (FPV) have become an increasingly attractive application of photovoltaics; however, much more research is needed on the co-benefits and impact of FPV systems on the nexus of energy, water, and food (EWF) systems. This paper, published in Sustainability, reviews the suggested co-benefits of FPV systems with a focus on the impacts that could alleviate pressure on EWF systems. The paper suggests that some benefits, such as improved panel efficiency and reduced land usage, have been properly corroborated in the literature; however, other benefits, such as water quality impacts, require further research.