The Solar Energy Technologies Office (SETO) Lab Call FY19-21 funding program will enable U.S. national laboratories to advance the secure and affordable integration of solar energy onto the U.S. electric grid. Projects will provide foundational analysis and evaluation of solar integration challenges, as well as strategies for advancing power system planning and operation, power electronics, sensors and communication technologies, and cybersecurity.
Researchers at the national labs will also conduct market analysis and explore concentrating solar-thermal power and photovoltaics research as a part of this effort. Learn more about the SETO Lab Call FY19-21 projects.
APPROACH
These projects aim to improve the integration of solar energy on the grid by advancing new technologies and developing and validating new modeling techniques. Projects will advance power electronics designs and technologies, enhance visibility and coordination of solar energy and other distributed energy resources (DER) on the grid, develop new sensors and communication technologies, and develop models that better predict solar power generation. Researchers will also develop and evaluate innovative technologies and system designs that can better integrate solar with energy storage, building controls, and other DER. Researchers will evaluate new solutions through simulations and field tests and use machine learning to improve modeling accuracy.
OBJECTIVES
As solar energy continues to grow in the United States, these efforts could improve grid resilience and reduce solar energy curtailment via energy storage and control technologies. Improved analysis of integration challenges will enable grid operators to better plan for future grid demands and allow the solar industry to develop new tools and system designs that could improve grid reliability and cybersecurity with high penetrations of solar energy.
AWARDEES
Project Name: Smart Photovoltaic Inertia Control Based on Real-time System Inertia Awareness
Lab: Oak Ridge National Laboratory
Location: Oak Ridge, TN
Principal Investigator: Yilu Liu
Project Summary: This project team will develop and validate smart virtual inertia controls for photovoltaic (PV) inverters in order to improve PV system performance and lower operating costs. Existing PV inertia controls have set parameters that make it difficult for them to coordinate with dynamic interconnection inertia levels, leading to poor control or wasted PV power reserve. This team will develop an ambient, measurement-based method to estimate system inertia that makes each PV inverter aware of system inertia in real time, enabling the inverter to adjust its own inertia without communication controls. This technology will be integrated with a commercial PV inverter, then tested with a simulation model that mimics interconnection for a PV system.
Project Name: Innovative Protection Systems for High-Pen PV Grids
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Kumaraguru Prabakar
Project Summary: This project team will develop new protection systems to enable faster identification and location of electric faults in distribution grids or microgrids with high solar photovoltaic penetration. Existing grid-modeling software platforms lack the capability to simulate traveling waves, which are bursts of high energy that travel almost at the speed of light and can be used to detect a fault. Instead these platforms rely on large fault currents from traditional generators. The traveling waves generated during a fault will be used to trigger protection systems in order to locate and clear the fault much faster than current methods. This project will also develop the software and hardware platform needed to simulate and test the solution.
Project Name: Multi-time-scale Integrated Dynamics and Scheduling for Solar (MIDAS-Solar)
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Jin Tan
Project Summary: This project team will create and validate advanced grid models by developing simulation models that seamlessly and cost-effectively combine dispatching and dynamic response analysis, where dispatching ranges from a day ahead to minutes, and dynamic response from seconds to subseconds. To study the impacts of photovoltaic (PV) variability on system reliability at different times, the team will develop a multi-time-scale grid model and an integrated PV model. These models will give operators a more complete understanding of how short-term PV variability affects transmission-system operations like reserve scheduling and energy deployment. They will also help operators accurately assess system reliability when deploying energy and reserve-scheduling under transient instability events, such as the failure of a major generator, and allow them to see how quickly standby generators can ramp up. The team will study interactions among all types of essential reliability services provided by PV power plants.
Project Name: Protection of High-Pen Distributed PV
Lab: Pacific Northwest National Laboratory
Location: Richland, WA
Principal Investigator: Thomas McDermott
Project Summary: This project will define best practices for power system protection—independent controls that isolate faults on the grid—for radial distribution circuits with high photovoltaic (PV) penetration. A radial system is a common type of power distribution system. Because high PV penetration creates bidirectional power flow, and inverters respond differently to faults, traditional protection methods need to be revised. PV and battery energy storage inverters produce low-fault currents that don’t function properly under traditional overcurrent and distance protection. And with new requirements in new industry standards, like IEEE 1547, devices known as undervoltage relays can’t detect faults. This project will evaluate potential local solutions—such as high-energy traveling waves, incremental quantities, relays without settings, and focused directional methods on distribution networks—and conduct field tests at two sites. These alternative protections have the potential to overcome costly special protection studies and other grid integration requirements.
Project Name: Mitigating Phase Unbalance for Distribution Systems with High Penetration of Solar PV
Lab: Argonne National Laboratory
Location: Argonne, IL
Principal Investigator: Daniel Molzahn
Project Summary: This project will develop control strategies for solar photovoltaic (PV) inverters that mitigate power quality issues related to phase unbalance on weak or rural electric grids. For large commercial buildings and other big energy users, energy is delivered in three balanced phases, but in rural grids the load and generation are connected to single phases, resulting in a phase unbalance, higher losses, and potential service interruption. This team will study a variety of approaches, including a decentralized approach based solely on local measurements and a grouped approach based on small sets of loads and PV generators. A centralized approach will leverage measurements from different locations, including smart meters, in order to compute optimal set points for each inverter. The controllers will be simulated on actual distribution system models from electric cooperatives.
Project Name: Physics-Based Data-Driven Grid Modeling to Accelerate Accurate PV Integration
Lab: Sandia National Laboratories
Location: Albuquerque, NM
Principal Investigator: Matthew Reno
Project Summary: Uncertainty in distribution grid modeling can lead to inaccuracy in decisions regarding photovoltaic (PV) integration, limiting the number of PV systems that can connect to the electric grid. This project will increase the precision and accuracy of distribution system models by more efficiently processing grid measurements. The team will then develop several physics-based, data-driven, machine-learning algorithms that will enable distribution grid models to dynamically adapt to changing grid conditions. This will enable usability for all distribution feeders with monitoring. The team will validate the algorithms to improve modeling accuracy and decrease uncertainties in PV hosting capacity by at least 90 percent.
Project Name: AC and DC Hybrid Distribution Grids with Solar Integration: Architecture, Stabilization, and Cost Assessment
Lab: Argonne National Laboratory
Location: Argonne, IL
Principal Investigator: Dongbo Zhao
Project Summary: This project will analyze the potential of hybrid alternating current (AC) and direct current (DC) distribution grids. This is a change from the AC-only grids currently used that require PV to be converted to DC, although DC could also benefit electric vehicle charging, batteries, LED lighting, and other technologies. The concept of DC nanogrids, microgrids, and medium-voltage distribution grids has drawn increasing attention in both academia and industry. In an effort to maximize the benefits of DC grids in terms of system cost, efficiency, and operation performance amid the challenge of reliable control under high penetration of intermittent solar energy, the team will develop controls for a hybrid AC/DC grid. They will use a universal impedance-based stabilization approach, with a decentralized and adaptive impedance loop to provide DC section and AC section stabilization, and add interface inverters that interlink AC and DC subgrids.
Project Name: Securing Inverter Communication: Proactive Intrusion Detection System Sensor to Tap, Analyze, and Act
Lab: Sandia National Laboratories
Location: Albuquerque, NM
Principal Investigator: Shamina Hossain-McKenzie
Project Summary: Inverters, which connect solar energy systems to the grid, can improve the hosting capacity of distribution grids, but interoperability, access interfaces, and the proliferation of third-party software applications have made smart inverters more susceptible to cyberattacks. This project will design a distributed monitoring system to observe a wide range of cyberattack paths, detect various attack methods, predict adversarial movements, and implement controls that mitigate damage to distributed energy resources (DER), like solar energy systems and other devices connected to the grid. The team will develop and test a cost-effective device-level solution called the Proactive Intrusion Detection and Mitigation System (PIDMS) in order to effectively protect and defend DER.
Project Name: Open-Source, Fault-Tolerant Grid Frequency Measurement for Solar Inverters
Lab: Oak Ridge National Laboratory
Location: Oak Ridge, TN
Principal Investigator: Lingwei Zhan
Project Summary: During grid faults, photovoltaic (PV) inverters may not reliably report accurate data, causing unwanted solar energy system shut-downs and putting the reliability of the grid at risk. This project will develop a fault-tolerant frequency measurement algorithm designed with high accuracy and low computational complexity. The team plans to open-source this algorithm so that it’s easy to implement on different types of solar inverters. This project aims to ensure future PV inverters are able to ride through typical system faults. The team will evaluate the reliability and accuracy of the algorithm under different fault conditions using industry benchmark models and perform testing with FNET/GridEye sensors—a frequency measurement network that captures dynamic grid behaviors.
Project Name: Robust DERMS Control Verification
Lab: Lawrence Livermore National Laboratory
Location: Livermore, CA
Principal Investigator: Dr. Jovana Helms
Project Summary: Implicit trust in the control commands issued by distributed energy resource management systems (DERMS) to solar inverters presents a cybersecurity vulnerability to the power grid. This project will address this risk by using advanced analytics to verify the commands sent by the DERMS control center. The team will develop techniques to approximate the state of the grid and DERMS control algorithms—independently of the DERMS—so local controllers can verify that a DERMS command is valid based on current conditions. Distributed energy resource components can then operate independently, even if a communication link between DERMS and local controllers is down, increasing the resilience of the system.
Project Name: Artificial-Intelligence-Driven Smart Community Control for Accelerating PV Adoption and Enhancing Grid Resilience
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Xin Jin
Project Summary: This project will address challenges in community-scale coordination of behind-the-meter resources by building on the National Renewable Energy Laboratory’s efforts on home energy management, grid hosting capacity, and device characterization for grid services. Using smart meter data, the team will develop artificial intelligence that can learn to identify homeowner preferences and enable day-ahead planning. The project aims to evaluate how to best use solar energy paired with flexible building loads like electric water heating or electric vehicle charging. Since solar energy is intermittent, the algorithms will try to schedule the loads when the sun is out. When there is excess solar energy, the project will determine the smallest battery energy storage (BES) system so the community can use that energy later in the day. This analysis will provide insight into cost-effective ways to minimize the need for BES systems. The team will validate the solution using hardware-in-the-loop laboratory testing, which simulates real-time embedded systems, and field demonstration in a net-zero-energy community.
Project Name: A Data-Driven Multi-time-scale Predictive, Proactive, and Recovery Optimization Framework for Solar Energy Integrated Resilient Distribution Grid
Lab: Argonne National Laboratory
Location: Argonne, IL
Principal Investigator: Chen Chen
Project Summary: This project team will develop resiliency planning for microgrids supported by solar photovoltaics. The team will develop a pre-event, proactive energy management optimization model and solution that enables flexible load, storage resources, and distributed solar energy to be strategically prepared for dispatch in the event of a grid disturbance, like extreme weather. They will also develop a post-event, real-time operation optimization model and solution. These microgrid and solar solutions have the potential to improve grid operations and provide microgrid islanding, without power from the electric grid, for up to five days.
Project Name: Reconfigurable and Resilient Operation of Network-Controlled Building Microgrids with Solar Integration
Lab: Argonne National Laboratory
Location: Argonne, IL
Principal Investigator: Chen Chen
Project Summary: This project will develop a reconfigurable distribution grid framework for reliable and isolated operation through the dynamic integration of neighboring microgrids. This is one of the first steps toward creating a grid of microgrids. Researchers will focus on the load, storage, and solar photovoltaic device level to enable frequency- and voltage-regulating capabilities in buildings that have solar energy storage with grid-forming inverters and controllable loads. The team will further develop these technologies and work toward the dynamic integration and separation of neighboring microgrids, which will be tested in the field.
Systems Integration Core Support Projects
Project Name: Core #3: Power Electronics Reliability Standards
Lab: Sandia National Laboratories
Location: Albuquerque, NM
Principal Investigator: Jack Flicker
Project Summary: This project will assess photovoltaic (PV) converter and inverter reliability, since reliability and failure mechanisms of PV power electronics are key cost drivers. The team will conduct testing to quantify the difference in reliability attributed to nonstandard operating conditions, compare the effects of potting and component layout to reliability temperature gradients, and evaluate the equivalency of different reliability tests. This data will directly impact the standards-making process for PV power electronics devices and will conclude with the publication of a testing and qualification standard for PV power electronics.
Project Name: DER Cybersecurity Standards Developments
Lab: Sandia National Laboratories
Location: Albuquerque, NM
Principal Investigator: Jay Johnson
Project Summary: This project will create cybersecurity standards for distributed energy resources (DER), including solar inverters, for new products entering the market and operating in the field. Specific DER cybersecurity requirements will be included in communication protocol standards, interconnection and interoperability standards, and grid operator and aggregator architecture requirements. Sandia National Laboratories and the National Renewable Energy Laboratory will coordinate standards development with stakeholders, lead working groups, and accelerate codes and standards development through in-person and virtual participation. Researchers will also conduct the technical research and development required to validate the test procedures and recommendations within these standards.
Project Name: Solar Radiation Research Laboratory
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Manajit Sengupta
Project Summary: This project will fund the Solar Radiation Research Laboratory to maintain and test solar measurement devices and ensure they are certified for accuracy and precision. The team will operate the Baseline Measurement System to provide high-quality, long-term solar and atmospheric measurements. These measurements can be used for instrument comparison and development, standards development, the development of radiative transfer and solar variability models, and validation studies. This project will maintain the national standard for solar measurements and disseminate accurate solar measurement and modeling methods and best practices.
Project Name: The National Solar Radiation Database
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Manajit Sengupta
Project Summary: This project will develop and provide public access to high-quality, long-term solar resource data sets through the National Solar Radiation Database (NSRDB). These data sets encompass studies from the U.S. Department of Energy and solar industry in grid integration, capacity expansion, resource planning and deployment, national energy modeling, production cost modeling, and regional solar deployment. The team will update NSRDB to provide timely data, incorporate new information from the Geostationary Operational Environmental Satellite system, and improve data set quality through regular research on identified weaknesses.
Project Name: Accelerating Systems Integration Standards II
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: David Narang
Project Summary: This project will update standards in interconnection and interoperability of solar PV and other distributed energy resources (DER) at the distribution level. The team will lead the updating of conformance testing standards to reflect the industry standard from the Institute of Electrical and Electronics Engineers. To tackle emerging system integration challenges, the team will also develop guidance such as operational best practices for bulk power systems with high levels of PV and integration of distributed energy storage. Improved practice recommendations and certification standards for end-to-end interoperability of DER will also be developed.
Project Name: Foundational Open-Source Solar System Modeling through Improvement and Validation of the System Advisor Model and PVWatts
Lab: National Renewable Energy Laboratory
Location: Golden, CO
Principal Investigator: Janine Freeman
Project Summary: This project will leverage the National Renewable Energy Laboratory’s open-source System Advisor Model (SAM) and PVWatts platforms to provide the solar community with valuable and extensible photovoltaic (PV), battery, and financial modeling resources and tools. The team will work to maintain software, provide technical support and PV model improvements, and increase stakeholder engagement activities for the continued use and relevance of these platforms in order to foster a vibrant, open-source community around the SAM and PVWatts tools.
Learn more about SETO’s systems integration research and the other SETO Lab Call FY19-21 projects.