Grid Integration Facilities at the National Wind Technology Center
NREL's crosscutting, multimegawatt grid integration research facilities at the National Wind Technology Center (NWTC) are providing a launch pad for industry partners to evaluate how large-scale energy systems interact with our grid as new energy technologies and the nation's grid infrastructure evolve.
Large penetrations of wind and solar energy resources are increasingly being introduced to our power grid, requiring careful evaluation and validation for the secure and reliable integration of these technologies. To accommodate this growth, the NWTC's 305-acre site features vast areas dedicated to existing and future grid integration facilities, providing advanced research capabilities for the integration of large-scale energy systems.
At the NWTC, researchers can configure more than 8 megawatts (MW) of installed, large-scale wind turbines, photovoltaic (PV) systems, and energy storage in a variety of ways to analyze the effects of large-scale deployment of variable generation on the grid. NREL's controllable grid interface (CGI), a 7-megavolt ampere (MVA) system, provides the ability to emulate a wide range of grid conditions. The CGI is ideally suited for grid integration research with MW-scale wind and PV technologies, as well as energy storage devices, transformers, and protection equipment at medium voltage.
Integrating large amounts of renewable energy into the grid requires advanced control systems, new grid system designs, and the validation of models for those new systems. NREL's grid integration research provides electric power operators with the tools and resources they need to more efficiently manage power system operations.
AES and First Solar PV systems provide a testbed for advanced grid integration research and control system validation, coupled with energy storage and other advanced technologies. This capability supports the industry trend toward large-scale hybrid wind, solar, and energy storage plants.
MW-scale wind turbines provide a testbed for advanced grid integration research and controls system optimization, coupled with energy storage and other advanced technologies. This capability supports the industry trend toward large-scale hybrid wind, solar, and energy storage plants.
The NREL 1-MW/MWh battery energy storage system (BESS) provides as fast as 50 millisecond response times to grid events. The BESS offers a platform for energy storage research and demonstration of improved grid services, including synthetic inertia, fast frequency response, power oscillation damping, active power flow control, reactive power and voltage control, transient fault ride-through, and more. The site also hosts two lithium-ion MW batteries with hosting capacity for four other MW-scale energy storage systems.
Dynamometers validate wind turbine drivetrains by replacing the rotor and blades of a turbine with a powerful motor to simulate operation. They employ model-in-the-loop techniques to emulate rotor, tower, pitch, and yaw systems with computer simulations operating in real time. NREL's 2.5-MW and 5-MW dynamometers can be connected to the CGI for grid integration research, including back to back inverter systems validations.
Advanced sensing, measurement, and forecasting capabilities are incorporated with new generation and load controls to enable advancements in grid operations and controls research. Connection to NREL's High Performance Computing Data Center enables the simulation of massive data flows such as atmospheric inflow, wind turbine loads, electricity generation, and real-time electricity prices to validate new system controls and forecasting over different timescales.
The CGI is a 7-MVA system, with 39 MVA short circuit capacity for 2 seconds, that provides the unique simulation capability of a flexible controlled grid. This capability can be used for validating various types of reliability services under fully controlled grid contingency scenarios and different interconnection conditions, such as strong or weak grids. The CGI enables validation of new grid technologies and control systems, significantly reducing certification time for hardware performance validation while providing system engineers with a better understanding of how wind turbines, photovoltaic inverters, and energy storage systems react to disturbances on the electric power system.
In conjunction with the CGI, researchers use RTDS technologies to simulate regional power flow for actual utility operation including grid-disturbance events, such as a weather-induced outage. RTDS systems enable power and controller hardware-in-the-loop research capabilities, allowing researchers to validate the operation of advanced wind, PV, and energy storage for grid services, including frequency stability, transient stability, and voltage stability. With the CGI and network of installed phasor measurement units (PMU), RTDS systems can conduct power hardware-in-the-loop experiments for large-area stability controls as well as advanced impedance-measurement based stability controls.
High performance computing and visualization at NREL propel technology innovation as a research tool by which scientists and engineers find new ways to tackle our nation's energy challenges—challenges that cannot be addressed through traditional experimentation alone. By including a virtual link from the CGI to the Energy Systems Integration Facility’s HPC systems, researchers and industry partners can visualize complex systems in a virtual environment and observe advanced, real-time testing schemes that combine the flexibility of the CGI with the ESIF’s grid simulator and smart-grid capabilities.
Control of NWTC wind, solar, and energy storage systems are coupled to real-time electricity market price signals to validate system optimization for different electricity markets, including day-ahead energy and ancillary service markets.
The site can connect and disconnect from the utility grid to operate as a microgrid in grid-connected or island mode. In island mode, the site provides its own voltage source, interconnected loads, and variable generation is controlled to maintain stable grid conditions as they act as a single controllable entity with respect to the grid.
These capabilities are providing our partners in industry, academia, and government with a unique opportunity to validate, optimize, and visualize the grid integration performance of emerging energy technologies before they are deployed.
Grid integration research at the NWTC is currently focused on:
- Active power control, ancillary services, and synthetic inertia supplied by wind and solar systems
- Control systems and new plant designs for wind, solar, and energy storage
- Advanced forecasting methods for wind and solar resources, coupled with real-time system control
- Demonstration of distributed network control with autonomous energy grids
- Evaluation of dispatchable wind and solar plants coupled with energy storage
- Advanced power electronics solutions that increase electric grid flexibility, reliability, and resiliency
- Power system solutions that incorporate high-performance computing with advances in power system optimization, optimal power flow, and grid state estimation.
A Cross-Lab, Cross-Industry Hub for Innovation
This work converges cross-cutting research and development from all corners of NREL's science and technology programs into one expansive, interconnected network. For optimal performance, the site relies on NREL's brightest minds among the lab's solar, wind, energy systems integration, energy storage, power systems, and weather forecasting researchers. The site is also being expanded to include energy systems integration with advanced buildings, thermal generation, and hydrogen fuel cell technologies, enabling the real-time integration of electricity and energy systems as a paradigm for the grid of the future.
These grid-integration capabilities have become possible through a variety of partner-developed technologies, including wind turbines from the U.S. Department of Energy, Siemens/Gamesa, GE/Alstom, RES Americas' energy storage system, AES and First Solar PV and energy storage platforms, Schweitzer Engineering Laboratories real-time automation controller technologies, ABB, SMA and GP Tech MW-scale inverters, and MW-scale batteries from LG and Samsung.
Multi-lab efforts are also benefiting from NWTC's transmission-level grid integration research, including the DOE American Microgrid Platform (AMP), a national coordinated microgrid research capability, Beyond Batteries, a DOE program expanding energy storage research, and the Grid Modernization Lab Consortium, a strategic partnership between DOE and national laboratories to modernize the nation's grid.