Researchers at Oak Ridge National Laboratory recently demonstrated a new technology to better control how power flows to and from commercial buildings equipped with solar, wind or other renewable energy generation.
“We are creating an electric grid of the future that allows renewable energy to be deployed in the most effective way,” said ORNL’s Madhu Chinthavali, who leads the research. “With this new grid interface architecture, operators can control energy flows much more meaningfully, even when power generation is decentralized.”
Renewable energy is key to helping the U.S. electricity sector achieve national decarbonization goals. But they also add uncertainty to the electrical grid because they are unevenly available across the country and generate electricity intermittently. Developing and coordinating power electronic systems to incorporate these resources more easily is vital to creating a more resilient grid for reliable electricity.
Chinthavali’s research team designed a hybrid AC/DC power electronics hub to act as a gatekeeper between the larger grid and subsystems including renewables, generators and battery storage. The technology was developed and tested in the Department of Energy’s Grid Research Integration and Deployment Center, or GRID-C, at ORNL.
GRID-C offers a unique platform for building power electronics systems, starting with the smallest component, then testing and demonstrating full systems that incorporate both hardware and simulation. In the low-voltage lab, rows of metal containers house ORNL-developed power electronic converters, trailing cords thicker than a wrist and ending in plugs as wide as a plate. These converters provide different levels of power to electrical feeds based on different scenarios. They are paired with equally large power emulators that can mimic energy delivered by a solar array or a battery system. Huge touchscreens allow engineers to rearrange the system and tweak its operation.
ORNL engineers designed the power electronics hub to control how the converters interact with each other and the grid. Emulators are set up to mimic the electrical draw and generation of a solar array, a storage battery, an emergency generator and a critical data center with high electrical demand. The power electronics hub was programmed to autonomously manage the power flow of all these electrical loads, helping prevent fluctuations in supply and demand on the wider electrical grid.
The power electronics hub plays the role of a middle manager between the larger electric grid and the local power electronics. “Instead of the utility talking to, say, a million resources, this technology reduces that number by a factor of 10,” said ORNL’s Michael Starke, lead software architect for the project. “From a utility’s point of view, all the equipment managed by the power electronics hub functions as a single system.”
This is an advantage for power companies faced with incorporating distributed and intermittent energy from solar, wind, geothermal and other renewable sources into a century-old grid that was designed to push steady flows of energy out from centralized power plants.