NREL’s Energy Systems Integration Facility – Testing a Smart Grid Future

 By Ben Kroposki

The National Renewable Energy Laboratory opened the Energy Systems Integration Facility (ESIF) with the idea to help industry conduct ground breaking research on energy systems that integrate a wide range of energy carriers and sources-solar and wind energy, batteries, electric vehicles, smart homes, heating and cooling systems, hydrogen fuel cells, and communications, to examine how technologies can work together in an efficient, holistic system. The research in the ESIF is helping the world's energy infrastructure move toward a flexible, connected future and is at the forefront of smart grid research and testing.

In less than two years, the U.S. Department of Energy’s Energy Systems Integration Facility (ESIF), located at the National Renewable Energy Laboratory (NREL) in Colorado, has already started to make a difference in integrated energy research.

Why integrated energy research and smart grid testing?

By thinking about fully integrated energy systems, the research in the ESIF helps the world’s energy infrastructure move toward a flexible, connected future. Energy systems integration examines a wide range of energy carriers and sources—electricity, thermal and fuels—and incorporates other infrastructures, like water and communications, to examine how technologies can work together in an efficient, holistic system. With a focus on the connections between electricity system and data, information, and communications infrastructures, ESIF also is at the forefront of smart grid research and testing.

Some examples of research questions addressed at the ESIF include:

How will new hardware and software work within the utility system?

  • With hardware in the loop (HIL) testing, the ESIF connects operating technologies such as PV inverters, energy storage system, and electric vehicles with simulations of much larger grids. A large-scale PV inverter can connect to the ESIF’s 1.5-MW solar array simulator, grid simulator, and load banks to test the hardware in a realistic power environment. To uncover the impact of these new technologies in the context of a larger system, the ESIF uses software to simulate the actual electric distribution circuit and ensures new, innovative hardware works with the utility system at actual load levels before it is implemented.

How will a microgrid perform under various load conditions?

  • ESIF researchers test complete microgrids and advanced inverters with energy storage, diesel generators, renewable energy sources, and simulated load conditions. These microgrids can be fully tested before being deployed in locations to improve customer reliability and resiliency.

How will larger-scale deployments of smart appliances affect the rest of the power system?

  • The ESIF’s smart home testing lab connects appliances, a home, or even a community to an end-to-end energy ecosystem. By incorporating power generation, energy storage, and end loads into the lab, researchers can simulate real-world conditions in a controlled laboratory environment. This also helps utilities understand the impact of consumer owned and operated equipment on the power system.

How will an energy storage component perform under various environmental conditions?

  • In the ESIF’s large-scale environmental chamber, researchers can test megawatt-scale energy storage components in a variety of environmental conditions like those encountered in field deployment.

How do smart grid components react to grid disturbances?

  • NREL’s controllable grid interface (CGI) system at the National Wind Technology Center can reduce certification testing time and costs while providing system engineers with a better understanding of how wind turbines, PV inverters, and energy storage systems react to grid disturbances and provide various ancillary services back to the grid. The CGI’s capabilities allow industry to partner with NREL to test, optimize, and visualize the grid integration-related performance of a unit before it is deployed in the field. Through a virtual link with the ESIF’s super-computing capabilities, researchers and industry partners can enhance visualizations of complex systems in a virtual environment, and realize advanced real-time testing schemes combining CGI’s extreme flexibility with ESIF’s grid simulator and smart grid capabilities.

What role can plug-in electric vehicles play in a smart energy system?

  • Researchers examine the interaction of building energy systems, utility grids, renewable energy sources, and plug-in electric vehicles, integrating energy management solutions and maximizing potential greenhouse gas reduction.

Testing Smart Technologies in an Energy-Efficient Environment

The ESIF itself received a Platinum Designation from the U.S. Green Building Council for Leadership in Energy and Environmental Design (LEED) and a 2014 Sustainability Award from the U.S. Department of Energy. The ESIF houses Peregrine, the largest high-performance computing system in the world exclusively dedicated to advancing renewable energy and energy efficiency technologies. Waste heat from Peregrine is used to heat the ESIF, significantly reducing thermal energy costs.

Supporting Industry Innovators

Just one example of the ESIF’s success in demonstration and testing for industry innovators: NREL partnered with Raytheon, Primus Power, and Advanced Energy to demonstrate an advanced microgrid system that draws on batteries and solar energy for its power. To test this technology, NREL built a replica of the microgrid system in the ESIF and tested it in both islanded and grid-connected modes, including the transition between modes. The demonstration proved that an energy storage system-driven microgrid with conventional PV inverters can achieve 100% PV penetration while retaining the power quality needed to satisfy critical facility loads, reducing operational costs, logistical burden, and carbon footprint. Using this pilot system’s technology, the fielded microgrid installed at Marine Corps Air Station Miramar will be able to maintain power to base facilities under many adverse conditions—including loss of the local power grid. For more information visit the NREL ESIF website at:




Ben Kroposki, an IEEE Fellow, is Director of the Power Systems Engineering Center at the National Renewable Energy Laboratory (NREL), where he leads NREL’s strategic research in the design, planning and operations of electrical power systems. His expertise is in the design, testing and integration of renewable and distributed power systems, and he has more than 115 publications in these areas. As an IEEE Fellow, Dr. Kroposki was recognized for his leadership in renewable and distributed energy systems integration. He has served on a number of IEEE technical standards working groups and chaired IEEE 1547.4, the first international standard on microgrids. He has also served as an editor for the IEEE Journal of Photovoltaics, IEEE Transactions on Sustainable Energy, and IEEE Power & Energy Magazine. He received his B.S. and M.S. in electrical engineering from Virginia Tech and Ph.D. from the Colorado School of Mines.

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