Automation Is Key to Managing a More Complex Power Grid. These Projects Show How It Could Work.
As Customer Energy Products Multiply, Electric Utilities Find the Controls They Need at NREL
The research area of autonomous energy systems structures the electric grid into cells. Each cell contains resources that allow it to power itself as a microgrid, or to connect to the larger grid and share power. This cellular architecture has the advantage of being adaptively connected and resilient. Image by Getty Images
It used to be so simple: Electricity started with the power plants and ended at the homes and businesses. Now there is power coming from the opposite direction, a few more electrical connections at each building, and a lot more data.
As we update power systems to accommodates these changes, there is an opportunity to design adaptivity and intelligence into how electricity works for people, and the controls to do it are already available. In the autonomous energy systems portfolio, researchers at the National Renewable Energy Laboratory (NREL) have made a menu of controls that deconstruct the grid into autonomous cells. Using artificial intelligence (AI) and distributed computing, their controls scale to an unlimited number of devices, and they are ripe for utilities, campuses, companies, and communities to make the most of local energy resources. Some are already taking advantage, and here is how.
Controls for Energy Equity: Consumer Aware Algorithms
NREL’s controls are couched in the language of optimization, but optimal what? That is for the humans to decide, so NREL developers optimized for energy justice in a U.S. Department of Energy (DOE) Office of Electricity-sponsored project named DynaGrid.
The research team measured household vulnerability using data from the U.S. Census Bureau, Federal Emergency Management Agency, and other sources. They identified where people require electricity for medical supplies, where people cannot financially cope with outages, and where people are at a higher risk of natural disasters. With that information, they formulated an optimization problem: how to dynamically partition a neighborhood into reliable and equitable networked microgrids.
“It doesn’t help to have reliable electricity if you cannot afford it,” said Andrey Bernstein, the project principal investigator at NREL. Bernstein hosts an annual Workshop on Autonomous Energy Systems and manages a group of researchers who crafted the DynaGrid algorithms.
“We want to make sure that everyone will benefit from reliable electricity and have fair access to clean energy,” Bernstein explained. “DynaGrid achieves this by including socioeconomic metrics in design and operation of networked microgrids.”
For example, imagine when a utility preemptively cuts power to a neighborhood to mitigate wildfire risks.
“When planning which neighborhoods to de-energize, it is important to assure safe power to critical loads in terms of the frequency, location, and duration of outages,” Bernstein said. “DynaGrid is able to automate this process to avoid inequities.”
While the DynaGrid project will soon wrap up, work continues for the partner utility in Detroit, which has been awarded by the DOE Grid Deployment Office to “improve real-time response through adaptive networked microgrids.” The utility will have the chance to use NREL’s algorithms across its distribution area.
Controls for Bulk Grid Flexibility: Buildings Become Alive
Buildings use about 75% of all electricity in the United States, but with networked devices and controls they can be more than just an energy drain: They can be a profitable source of grid flexibility. This is the concept for a project named SmartGrid Advanced Load Management & Optimized Neighborhood (SALMON), funded by DOE’s Connected Communities program.
In SALMON, the Portland, Oregon, utility Portland General Electric aims to retrofit more than 575 buildings with “smart” (controllable and data-operated) devices like thermostats, water heaters, and solar and storage systems. The utility wants these devices to talk—not like an Alexa, more like appendages of a robot—so that they run with a collective purpose: to provide flexibility.
NREL is evaluating the potential of such an approach using NREL’s EdgeFlex utility and aggregator controls and home energy management system controls, depicted below, that animate building resources to adjust their energy and benefit the grid. From the project, the utility expects to add finer-level flexibility to grid management—possibly 1.4 megawatts of flexibility from two adjacent Portland neighborhoods.
The incentive for such flexibility rests in a recent rule, FERC Order No. 2222, that allows aggregated devices to participate in transmission markets. Simply put, buildings can sell power: either their excess power from solar generation or negative power by reducing demand. This opens revenue streams, new sources of power, and energy savings but also the challenge of orchestrating the devices.
NREL researchers modeled the neighborhood—its electric system, 4,000 residential units, and many devices—and interfaced it with NREL controls. In a later phase, the researchers plan to connect this model with the commercial management software that will be used in the field and simulate the energy and cost flow in real time. This is possible with the Advanced Distribution Management System (ADMS) test bed, which allows partners—including utilities, management software vendors, and associated nonprofits—to compare control schemes.
“Upon completion, scheduled for 2027, this project will be an early test of device aggregation,” said Annabelle Pratt, who leads NREL efforts on this project. Pratt is excited that, like other autonomous energy systems projects at NREL, “this project will contribute to the industry’s understanding of the advantages and obstacles of advanced energy management systems and widescale device automation.”
Controls for Critical Resilience: Reorganizing in an Emergency
Microgrids can keep critical sites powered during an outage, but only if the microgrids are electrically stable, inherently resilient, and have sufficient solar and storage nearby. Nobody wants to run those calculations in the middle of a disaster; the solution is better-off automated.
NREL leads a project to autonomously form stable and resilient microgrids, helping residents in the high mountains to remain electrified during wildfires and other emergencies.
REORG, funded by the DOE Solar Energy Technologies Office, has delivered controls that decompose a power system into its smallest possible subsets of independent microgrids and then clusters the microgrids together depending on real-time outage conditions to maximize resilience.
“Our methods are different from traditional microgrid controllers because they use AI to adapt to system uncertainties, reducing the dependency on accurate system models and communications,” said Fei Ding, project PI. “Also unique, we use resilience metrics and stability criteria to form and operate the community microgrids. This way, the community can adapt to time-varying outage conditions effectively.”
The NREL team validated this futuristic approach with the ADMS test bed. They connected the same hardware that the partner co-op has on-site—a smattering of solar, battery, and electric vehicle systems—into a replica of the co-op’s distribution network. They then simulated recovery following an outage, which proceeded according to plan: Stable cells formed, critical loads stayed powered, and the patchwork of microgrids autonomously stitched together again. All that remains in the project is a live field demonstration by the co-op.
Currents in Autonomous Energy Systems
While some algorithms are ready to hit “Go,” researchers are pushing deeper into areas that make sense to automate, including cloud cybersecurity for distributed energy resources and protection systems that identify abnormal electrical conditions. Researchers are also developing new tool sets for this work, built around AI for real-time bulk operations and grid-forming inverters for decentralized grid stability.
To partner with NREL in autonomous energy systems, contact Ty Ferretti, and learn more at NREL's website.