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A USB port for the grid: OpenFMB will provide plug-and-play interoperability and communications for grid-edge DERs

One of the thorniest issues of integrating distributed energy resources (DERs), microgrids and other advanced grid-edge technologies onto the electric grid is communications and control systems — especially as the number and complexity of these resources continues to grow.

Interoperability is another major challenge. The industry needs a “plug and play” solution to make it simple for new DERs to connect to the grid with full functionality, or for replacements to be made seamlessly.

One solution that Duke Energy, Pacific Northwest National Lab, Oak Ridge National Labs, National Renewable Energy Lab and several universities and researchers are working on is called OpenFMB — or Open Field Message Bus. A game-changing framework, OpenFMB allows DERs to be deployed across a utility’s distribution network with full visibility, interoperability, plug and play capability, and scalability.

Moving rapidly from concept to successful small-scale testing, the technology is now on the verge of an implementation at a local civic center in Anderson, South Carolina, which serves as a community shelter and operations center in the event of an emergency or disaster. Funded by the U.S. Department of Energy (DOE), the project is the result of collaboration between Duke Energy, the University of North Carolina – Charlotte, the University of Tennessee – Knoxville and the Grid Modernization Laboratory Consortium (GMLC), a group of experts drawn from the DOE’s national laboratories.

“OpenFMB essentially serves as a center for local message exchange, data analysis and command for DERs and other technologies at the grid edge,” said Aaron Smallwood, Vice President of Technical Services at the Smart Electric Power Alliance (SEPA), which was involved in the initial development of OpenFMB.  “Basically, it augments the central command and control used by legacy systems, and can increase resiliency – for example, restoring power more quickly after an outage.”

“On today’s grid, such speed is essential,” said Stuart Laval, Duke Energy’s Director of Technology Development and Co-chair of the OpenFMB users group. “Systems that used to only talk in minutes or hours will potentially have access to data in seconds or faster,” he said.

As the world moves toward the Internet of Things (IoT), with massive data sharing among devices to increase efficiency and automation, OpenFMB will allow DERs to leverage IoT technology to make the grid even more efficient.

“This project is an opportunity to demonstrate OpenFMB capabilities using commercially available equipment implemented within a traditional distribution system,” Smallwood said. “Successful implementation will move us closer to commercialization and broader industry adoption of the framework.”

The Duke project is now in design mode, as Duke and other members of the working group develop the engineering. Pieces of it will be installed by the end of 2019, with full implementation in 2020.

How It Works

OpenFMB solves a problem. As more commercial and residential solar panels, electric vehicles and other DERs are deployed, utilities need to have the option to move from centralized to distributed control to enable DERs to smooth out local grid congestion and increase resiliency. Another critical need is a flexible system that can adapt to a variety of inputs that could change significantly over time.

Further, DERs such as behind-the-meter batteries and electric vehicles (EVs) – as well as utility-owned assets such as microgrids — can’t integrate easily with existing control systems. Every time a new component is installed, it needs to be hardwired back to the utility’s central command center.

In this context, think of OpenFMB as the USB port on your laptop – you can plug in all kinds of devices, and your computer can recognize and interact with them. In most cases, the devices can interact with each other, as well.

Now imagine trying to connect and control devices without USB ports (or wireless alternatives). That’s what the industry is often doing with DERs today – hearkening back to the days when switching from one program or document to another required inserting a new floppy disk into the computer’s hard drive.

Traditional command and control network versus OpenFMB (Source: Smart Electric Power Alliance)

With OpenFMB, not only will new DERs and utility assets be interconnected more quickly and cheaply, but the direct and local communication between devices will reduce delays when responding to grid challenges such as outages and load peaks. Grid efficiency will be increased when grid-edge devices can share data and make local control decisions.

Duke’s first field deployment test of OpenFMB, at a microgrid test site, showed that the framework successfully enabled high-speed coordination between solar panels and a battery energy storage unit. Local communication between these types of devices will be needed to accommodate the expected rapid growth of commercial and residential solar, which could result in greater impacts on local grids. For example, California’s recent mandate for solar panels on all new home construction could mean significant power fluctuations at sunrise or sunset, or when clouds pass over different neighborhoods of solar homes.

When a nearby energy storage unit can adjust almost immediately, either by taking energy off or putting more energy on the grid, solar production swings will be manageable even with tens of thousands of units on the grid. But that fast-response flexibility requires distributed communications and control, rather than sending thousands of signals long distances to a central command-and-control system.

The Duke Energy implementation in Anderson will demonstrate that OpenFMB can enable distributed command and control with even more devices in a real-world setting. This demo will use a standards-based OpenFMB “harness” with utility-owned assets connected via commercial, off-the-shelf remote terminals, and non-utility assets connected using VOLTTRON, an open-source technology platform also developed by the DOE’s national labs. Communications between devices will occur using a leased 4G LTE network.

The implementation will coordinate operations between the Duke local distribution system and a battery-based microgrid at the civic center. In addition to validating OpenFMB’s overall viability, researchers will examine the effectiveness of self-healing systems designed to reduce the duration and frequency of momentary outages — and the ability to incorporate DERs to deal with longer-lasting system outages.

“This project is developing some of the final pieces to move OpenFMB forward at scale to meet the needs of the modern grid,” Smallwood said. “The team has been working on a very fast time frame, and the system architecture and tools they are creating will make this technology replicable for a broad range of applications that will make our electric system cleaner, safer, and more efficient and resilient.”

Nick Lanyi is a writer and consultant based in Washington, D.C. Email him at