Go down to the basement of your office building or apartment complex, or the garage of your home, and you’ll find a ubiquitous piece of electrical equipment that could be the next frontier for smart, connected energy management -- the circuit breaker. 

Circuit breakers are a multibillion-dollar market. Projections show a global market of between $13 billion and $19 billion by decade's end, dominated by giants such as Siemens, ABB, Schneider Electric, Eaton, Toshiba, Mitsubishi, and GE’s Alstom. 

Most of the circuit breakers out there are fairly simple, electromechanical devices that sit idle the vast majority of the time. But the latest versions are coming with features like wireless connectivity and computing power that are meant to turn them into something more like a smart meter or a smartphone. 

That, in turn, could allow utilities and building owners to start tracking the interplay of grid-supplied power and on-site distributed energy resources (DERs) like solar, batteries and plug-in electric vehicles, or demand response. As more and more buildings start to get these smart, networked circuit breakers, they could augment -- or even replace -- a lot of other equipment used for this purpose today. 

Eaton and EPRI test smart circuit breakers as virtual meters, load controllers

That’s the idea behind the field trial of Eaton’s energy management circuit breaker (EMCB). Last year, the electrical equipment giant started deploying its smart circuit breakers at about 500 homes with 12 U.S. utilities, including Duke Energy, Southern Company, CenterPoint, ComEd and Pepco. Over the next year, it will be working with the Electric Power Research Institute (EPRI) to see if they’re capable of collecting and sharing data accurately, receiving and sending controls to other smart equipment like thermostats or water heaters, and even shifting homes on and off of grid power during emergencies. 

“We’re trying to understand the functionality and potential value propositions for each device, working on utility-owned use cases,” Tom Reddoch, the EPRI senior technical executive in charge of the project, said in a recent interview. “This is a powerful device to control solar; it’s powerful to control storage; it’s powerful as a [measurement and verification] device.” They’re also particularly useful for electric vehicle applications, because they’re able to serve all the requirements of 240-volt EV charging equipment. "The charging infrastructure is being integrated into the breakers,” Reddoch said. 

Eaton and EPRI will have devices in the field through 2017, and by next year, they "should have sufficient field data to answer questions about the functional features,” he added. That will also provide feedback about potential modifications that Eaton may want to include in each device, he said. 

That’s valuable insight for Eaton, which is looking at ways to embed the technology across its product lines. "We’ve been in the circuit protection device business for years; it's in a nice place in the distribution ecosystem," Ron Thompson, Eaton's director of business development for emerging markets and new technologies, said in a recent interview. 

Each year, Eaton manufactures about 50 million poles -- individual 1-inch breakers -- for the circuit breakers it embeds in power distribution equipment like switchboards and panel boards, and "a percentage of those could eventually become smart breakers. Any time a building is built or retrofitted, that becomes part of the real estate of our products -- and if the breakers are intelligent, I don’t have to put a meter in or a relay for the circuit -- I don’t have to do a lot of things."

As EMCBs become standard equipment, they could start to serve as energy billing settlement and load control devices, similar to how smart meters function today, but down to individual circuits in homes and buildings, Thompson said. “The breaker has Wi-Fi communication built in, to connect to the Wi-Fi in the home,” he said. “In real time, if a utility is experiencing an under-voltage or under-frequency condition, we can measure it and respond,” he said.

Solid state technology -- the next step in smart circuit breakers? 

There are challenges in bringing new technologies to such an entrenched market, however. “The circuit breaker world has been one of the trickiest in terms of customer acceptance,” said John DeBoer, new product introduction manager for Siemens, in an interview last month. “It’s a classic industry that’s been really grounded in safety and reliable distribution of power. Their job is to sit there for a long time, and wait for that one moment when something unsafe happens in the electrical system. They’re trying to protect that wire.” 

Even so, Siemens is looking far ahead for the next generation of smart circuit breakers, including the latest in solid-state power electronics. In February, the German industrial giant invested in Charlotte, N.C.-based startup Atom Power, which has designed a solid-state circuit breaker that replaces the electromechanical features of a traditional device with digital power control. 

Solid-state circuit breakers have actually been around since the 1970s. "But the technology wasn’t ready, and the customers definitely weren't going to pay for them," DeBoer said.

But advances in solid-state power electronics have increased the capability and lowered the price of devices like these, he said. In terms of design, “the biggest thing that Atom Power has done well is they’ve gotten the solid-state device fully in series. It is sitting entirely within the conduction path,” he said. 

That makes Atom Power’s devices faster, and thus safer, than classic electromechanical systems, which take a few milliseconds to move, he said. “A solid-state device can move at the speed of a computer,” improving the device’s kilo-amperes interrupting capacity, or KAIC, a key measure of a circuit breaker’s ability to perform its core function of keeping electrical equipment safe from surges, arcs and other hazards. 

Beyond that, Atom Power’s integrated switches and panels can serve all the smart functions of an inverter or smart meter, he said. “The market for the metering of energy is absolutely exploding right now -- and it’s metering at all levels. I would say it has more than doubled in the past year or year and a half. The big trend is metering in buildings for multiple purposes at the same time. With the complexity of energy these days, and the growth in smart meters, it’s made energy more complicated and more confusing.” 

The drawback is that solid-state power electronics are still expensive. “These things are still five to 10 times more expensive than a traditional circuit breaker,” DeBoer said. “The incremental value, though, is that we’re seeing healthy year-over-year cost reductions, like you’re seeing in the semiconductor world.” 

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