If you think research scientists sit around in white lab coats tossing theories around without any practical engineering experience, think again. The National Renewable Energy Laboratory (NREL) recently launched its Advanced Research on Integrated Energy Systems (ARIES) platform, a computing environment designed to model today’s complex electric grid and support the development of new energy generation technologies and resilient microgrids. About two months into ARIES’ tenure, NREL’s Flatirons Campus—a facility that tests renewable energy systems—experienced a power outage caused by a utility transformer explosion. Because the damage occurred near the Flatiron connection to the main grid, the utility told NREL to expect several weeks without power.
Faced with the prospect of delaying their research, NREL administrators wondered whether the facility could go into self-sustaining mode until the transformer could be replaced. The lab-coat crowd replied, “Challenge accepted.”
Pulling Itself Up by Its Own Bootstraps
The Flatirons Campus microgrid is designed to be grid-tied with the ability to go into “islanding” mode (disconnecting from the grid and running independently) when necessary. So, NREL engineers isolated the microgrid and used its 1 MW / 1 MWh battery to power the control center. Once that was up and running, they used ARIES’ digital twin to see how the microgrid would respond to each power source. After simulating and validating a black start procedure, they connected the 430 kW solar array and the 1.5 MW wind turbine to keep the battery charged. Other systems were brought online until the facility—which draws about 200 kW—was fully capable of resuming its work and remained so until the transformer was finally replaced, and the campus reconnected to the grid. ARIES helped engineers turn a crisis into a case study in energy resiliency.
At the center of NREL’s Flatirons microgrid sits the controllable grid interface (CGI), which tests the mechanical and electrical characteristics of renewable energy technologies both on and off the grid. It is capable of simulating various fault conditions and evaluating the microgrid’s response. The CGI controls grid support systems, such as voltage and frequency regulation, reactive power (VAR) compensation, and load balancing. In addition to battery storage, two solar arrays and various wind turbines, the campus is home to a water power instrumentation lab, a three-megawatt load bank and three dynamometers that help wind turbine manufacturers test their generators under controlled conditions.