For the past year, Duke Energy has been pushing the envelope on grid interoperability with its Coalition of the Willing (COW) -- a group of six vendors that have opened their systems and devices to share data with one another in order to coordinate and automate their responses to changing conditions on the edges of the grid. 

Now Duke is expanding that coalition of vendor partners, and turning its attention to the next grid-edge integration challenge: microgrids.

That’s the news from this week’s Grid Edge Live conference in San Diego, where Jason Handley, director of operations and projects for Duke’s Emerging Technology Office, described the giant U.S. utility’s next phase in pushing standards-based interoperability into the mainstream.

Duke’s new project will be centered on building a microgrid at its new test lab in Mount Holly, North Carolina, close to one of its existing solar-battery integration test sites. The new facility will house inverter-based energy resources like solar panels and batteries, as well as a host of energy management and control devices to balance the site’s power, as well as interconnect it to the grid at large.

That’s a longer list of devices than those Duke has hooked up for standards-based interoperability in its work so far. It will also include devices that sit behind the meter, in the building itself, which hasn’t been part of the utility’s work to date. And as part of its goal of multi-vendor testing, Duke is planning to make sure that it brings in at least two makers of every class of device it will be testing, Handley noted.

Luckily for Duke, it’s having a much easier time getting vendors to join in on its new project, he said. The utility had to work hard to get its first six coalition partners -- Accenture, Alstom, Ambient, Echelon, S&C Electric and Verizon -- to sign up, he said. “Now we have 40 or more vendors coming to us,” he said, and so far the group has signed up an additional eighteen vendors on top of its original partners.

Stuart Laval, technology development manager for Duke’s emerging tech group, said the site will also include pad-mount transformers, reclosers, capacitor banks, line sensors, voltage regulators, and low-voltage power electronics devices of the type being built by startups like Varentec, Gridco and GridBridge.

As for standards, Duke’s current coalition members have been translating such industry-standard protocols as DNP3 and Modbus into messaging protocols like MQTT (for lightweight, low-overhead applications) and AMQP (for more robust messaging traffic). For its new project, Duke is planning to use a technology known as Data Distribution Service (DDS), a secured publish-subscribe messaging protocol originally developed by the U.S. Navy, as the protocol to link its devices, Laval said.

Duke has previously used communications hubs from Echelon and Ambient for its advanced metering infrastructure (AMI) deployments, but it is now searching for other partners for the millions more customers it has yet to connect with smart meters and distribution grid networks. In his presentation, Handley highlighted two new coalition members providing hardened grid computing devices that could serve as the hub for Duke’s field message bus architecture, which it intends to use for AMI, distribution automation and other services on the edge of the grid.

The first is Cisco, the maker of Linux-programmable grid routers now being used by Duke and smart meter partner Itron. Duke and Cisco have been working together for five years now, and Itron announced earlier this year that Duke planned to use its Cisco-linked technology for smart meter and distribution grid applications across its six-state service territory.

The second is National Instruments, which is providing Duke a ruggedized field controller of the same type it has deployed in support of advanced microgrid projects with Lockheed Martin and with Canadian utility Toronto Hydro.

Both of these vendors are “non-traditional utility providers that can really have an impact” on how utilities build out their grid edge networks, Handley said. Critically, both carry the memory, processing power and the flexibility to be reprogrammed to serve a variety of third-party applications that are becoming available. Duke is already writing algorithms to do voltage and reactive power optimization and solar smoothing (injecting battery power to compensate for drops in solar output as clouds pass overhead) at its test sites, and it is working on a microgrid synchronization algorithm that will allow the safe interconnection of onsite power and grid power, he said.  

Laval said that RuggedCom, the grid router vendor owned by Siemens, is also joining the coalition, adding a third potential provider of a distributed intelligence platform. As Handley noted during his presentation, part of Duke’s goal in its coalition work is to push traditionally proprietary grid technologies to open themselves up to interoperability, which “will lead to interchangeability” over time.

“We realize that this word may cause ripples with our vendors, and we understand,” he said. But “if our business model needs to change, our vendors business models need to change also.”

There are limits to how far those vendors are willing to go on this path, of course. Duke’s current coalition members have built open-source adapters for their devices, rather than opening their inner workings to Duke and its other partners.

At the same time, Handley noted, “open standards do not guarantee interoperability.” Duke and its Coalition partners will work on implementing standard protocols like the Object Management Group’s DDS, as well as on the common semantic models, like the Common Information Model (CIM), that allow disparate devices to understand one another’s references.

Finally, Duke wants to prove that all of its microgrid-linked devices can communicate quickly and reliably over wireless as well as wired communications in order to reduce the cost and complexity of deploying these systems in the future. While Duke’s emerging technology office doesn’t commercialize technologies, the utility is interested in examining the potential for developing all this technology as a service for customers outside its walls, he noted.

“We believe we can offer the microgrid -- if we can do it wirelessly, if we can do it cheaper. We’d like to be in the business of offering it as a service,” he said. “We’re trying to figure out the business models right now.” North American microgrid capacity is set to nearly double over the next three years, according to GTM Research's newest report, Microgrids 2014: The Evolution of Localized Energy Optimization -- and as Handley noted, utilities may well be the best equipped to manage microgrid deployment and integration into the grid at large.

Tags: ambient, batteries, cisco, derms, distributed resources, distribution grid, duke energy, echelon, energy storage, grid edge, gridbridge, gridco, itron, national instruments, ruggedcom