At the ARPA-E Energy Summit in Washington, D.C. last month, Smart Wire Grid had something of a coming-out party. The company has been around for a few years after growing out of Georgia Tech, but it was at the annual summit that Smart Wire Grid, a power flow controls company, was showcased as one of the successes of the Department of Energy’s research program.
Smart Wire Grid’s pilot with Tennessee Valley Authority was featured in a video between keynote sessions. But the Oakland, Calif.-based company is already moving beyond pilots with its first commercial customer, Southern Company.
Utilities are increasingly looking for solutions to make better use of existing transmission lines, as some might always be underutilized while others get overloaded. Last fall, Smart Wire Grid received nearly $4 million from ARPA-E as part of its Green Electricity Network Integration (GENI) program. Other universities, and companies like Varentec, AutoGrid and GE, are also looking for novel, lower-cost solutions for power flow control with funding from the GENI program.
The technology from the Georgia Tech spin-off involves 150- to 250-pound modules (essentially a single-turn transformer) that are clamped onto the transmission grid. The modules have a magnetic steel core with a secondary lining. When the secondary is opened, it injects inductance into the line and acts as a choke, according to Stewart Ramsay, CEO of Smart Wire Grid. When the line is choked, the power is rerouted over different lines.
“It allows you to valve the transmission line,” he said. “It’s not quite like a kitchen faucet, because you can’t go to zero.”
TVA is testing the technology as part of its Technology Innovation program. The utility has 99 devices across about twenty miles of transmission lines. The pilot will help determine what kind of congestion relief is needed, said DeJim Lowe, senior manager of grid modernization technology at TVA. “The idea down the line is that these would be dynamically controlled.”
The modules could be used in an outage situation to reroute power, or to help balance the flow of renewables across the transmission grid. Older technologies have been around for decades that can help control power flow on the grid, such as air-core reactors or traditional flexible alternating current transmission systems (FACTS), but they are centralized, said Ramsay. “The difficulty with all of the conventional technologies,” he added, “is that it’s all or nothing.”
Smart Wire Grid’s modules, on the other hand, can be wirelessly controlled by the grid operator over whichever communications protocol they prefer, or can be programmed to respond automatically when the line hits a certain loading point. In the past, the hardware needed for this sort of control on the grid would have been too heavy, even for transmission wires, but advancements in magnetic steel have allowed for cost-effective modules at a reasonable weight.
The advantage is also about space and time. The traditional technologies take up substantial space in a substation and can take a long time to install. TVA, which has had the devices up for about three months, said each module took about fifteen minutes to install, and the entire deployment took about four days. When compared to upgrading a transmission line, which could take months, the savings in downtime is significant. Smart Wire Grid has attracted a $10 million series A ($7 million of which has been paid out) from 3X5 Fund and RiverVest Venture Partners.
Currently, TVA, which has supported the technology since its development in 2005, is testing the modules to see if they perform as anticipated and then will run through different use cases over the next year. At Southern Company, which will start deploying 42 devices next week, the utility is interested in retiring some of its air-core reactors to use the substation space for other equipment, according to Ramsay.
Smart Wire Grid’s modules are not the right power flow control solution for every scenario. Ramsay noted that if a utility needs 50 percent more capacity on a line, the distributed technology cannot provide that, but for a line that’s overloaded up to about 15 percent of the time, the modules are a good fit.
Like some other next-generation power flow control technologies, the Smart Wire Grid modules provide a level of visibility on the transmission grid that operators have not had before. Although the company has built out a handful of business cases around different use scenarios, Ramsay said that when they sit down with utilities, “they bring up even more possibilities we haven’t thought of.”
Early talks with potential customers have revealed that it’s the flexibility of the devices that utilities are finding appealing. They don’t have to stay on the same transmission line for their entire lifespan; instead, the modules could be moved as more renewables are deployed or as transmission lines face new constraints.
For TVA, if the pilot were to go as planned (which is still too early to predict), the utility is already toying with the idea that the modules could be moved around to different locations.
Smart Wire Grid is currently focusing on the transmission grid, because Ramsay said that’s where the utilities are looking for solutions, but the company also has designs for a distribution grid module.