Over the past decade, startup Smart Wires has been taking on the novel challenge of digital controls for the high-voltage transmission grid.
It started in 2013 with a line-mounted device, the PowerLine Guardian, that proved it could throttle voltages in deployments with utilities on three continents — a useful task, but not the flexible power flow control it was aiming for.
Now, the San Francisco-based startup and ARPA-E award winner thinks it has a winning technology in the form of its SmartValve. Over the past three years, utilities including National Grid in the U.K., EirGrid in Ireland, and TransGrid and Western Power in Australia have deployed the devices with hopes of solving challenging transmission congestion and renewable integration issues.
“We’ve proven that the technology is viable and that there is a strong market,” said Jenny Erwin, director of strategic marketing. “Now we’re looking to scale up to meet global demand.”
The SmartValve is a “single-phase modular SSSC — a modular static synchronous series compensator,” Erwin explained in an interview last month. “It injects a voltage waveform in series with the line. This voltage injection has a controllable magnitude that’s independent of the line current. It can either lead or lag current by 90 degrees, meaning it can look like a series reactor or a series capacitor.”
Large-scale transmission system power-flow control devices are available and in use today. Usually called "flexible AC transmission systems," these devices are massive, expensive and purpose-designed to serve a relatively limited set of functions, Erwin said.
That limits their use to only the largest and most pressing transmission problems — and if those conditions change, they may no longer be useful.
Smart Wires' technology can solve these same problems but from a different point of view, Erwin said. “We offer power-flow control in bite-sized chunks,” with typical deployments ranging from substations with tens of SmartValves rated at 1 to 10 MVAr apiece, to pole-mounted or mobile configuration with as few as three, or one per phase.
A modular, scalable approach to transmission
That’s a “much more flexible way to invest in the system” than the all-or-nothing decisions usually faced by transmission planners, Erwin noted. It also offers the ability to start small and scale the investment over time, or to remove it and reinstall on a different voltage line — all use cases being explored with different utility customers.
Smart Wires is one of a handful of companies developing digital power-flow control systems that could revolutionize how power grids function, compared to the mostly electromechanical system in place today. But such companies face steep challenges and years of testing to prove they’re capable of performing as promised and can last for decades under extreme voltages and weather conditions.
The distribution grid has seen multiple startups emerge with power flow controls, such as Varentec, Ermco’s GridBridge and the now-defunct Gridco. But the transmission grid has been a more challenging environment, not just because of the higher voltages but also because of traditional ways of doing business that have emphasized overbuilding and reliability over technological innovation.
Transmission grids are lagging behind the growth of renewable energy, in terms of both building new transmission to carry it to the cities where it’s needed and integrating intermittent wind and solar into a system designed around constantly running generators.
With most new transmission projects taking up to a decade from conception to completion, the system is ripe for technologies that can increase the efficiency of the grid that’s already there.
“There are technologies that can be integrated into the grid fairly inexpensively, [and] that can relieve significant amounts of this congestion,” Jon Wellinghoff, chairman of the Federal Energy Regulatory Commission from 2009 to 2013, told Greentech Media.
Deployments in Europe, Australia to test power-flow capabilities
In the U.K., National Grid’s five-year framework agreement with Smart Wires calls for at least five SmartValve installations in 2020 and a long-range goal of increasing the capacity of its network by 1.5 gigawatts, at a much lower cost than the traditional alternatives to flexible AC transmission systems.
Ireland’s EirGrid tested Smart Wires’ PowerLine Guardian in 2015 but sees a far greater number of applications for the SmartValve, Jon O'Sullivan, the utility’s innovation manager, said in an interview last week. “It’s more flexible, quicker to build and solves a whole other range of issues that you can’t solve with the old technologies.”
Wind power supplied a record 29 percent of Ireland’s electricity in 2018, and this proportion is expected to grow even faster under the country’s renewable energy targets. EirGrid’s transmission networks are struggling to integrate that power efficiently, O'Sullivan said. In fact, a recent analysis showed that 90 percent of its primary transmission corridors were less than 10 percent loaded most of the time.
“If you could increase the share of loading on the lines to say, 50 percent, you could get more capacity out of your grid than you ever thought possible,” he said.
A study of Ireland's existing transmission upgrade plan indicated it could reduce the number of new transmission projects required from 16 to nine by using SmartValves to increase power flows through underutilized circuits if the technology works as promised, he said.
In Australia, utilities are examining how SmartValve deployments could help solve key transmission constraints for hydropower in New South Wales, improve grid reliability after coal plant closures in Victoria and reduce wind power curtailment in South Australia.
While Smart Wires hasn’t yet named any U.S. utility customers for its Smart Valve, several utilities have deployed its PowerLine Guardian devices, including Southern Company, Pacific Gas & Electric and Minnesota Power. “We see utilities leveraging learnings from these projects as they go forward with SmartValve projects.”
“We can’t solve every problem on the grid,” Smart Wires' Erwin said. But “before we build new power lines, we should make sure we’re utilizing everything we have today.”