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Clean energy journalism for a cooler tomorrow

New tools and tech to prep your electrical panel for an all-electric home

Solar, batteries, EVs and electric heat pumps can overload home electrical panels. Lots of companies are coming up with solutions.
By Jeff St. John

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A Span smart electrical panel installed on the side of a home next to an old-fashioned electrical panel with utility meter
Digital electrical panels like this first-generation Span unit are among the technologies that can help homes convert to all-electric appliances without time-consuming utility upgrades. (Span)

This is the second piece in a two-part series about home electrification. Read the first.

Barry Cinnamon, a longtime Silicon Valley solar entrepreneur and CEO of Cinnamon Energy Systems, is a big advocate of fully electric-powered homes. He’s also put his money where his mouth is, converting his own home heating and cooking — and the car he drives — to run on electricity supplied by his solar panels and battery as well as the grid.

Cinnamon identified a number of challenges to going all-electric — getting ahold of the latest high-efficiency heat-pump air and water heaters, finding contractors familiar with the technology and techniques for installing them, and combining various rebates and incentives to help shoulder the higher costs involved.

But one of the biggest potential stumbling blocks is out of sight and out of mind for typical homeowners: the electrical panel. These ubiquitous metal boxes full of circuit breakers are the conduits between household electrical circuits and the power flowing from utility power grids.

If they aren’t hefty enough to power the heaters, appliances or electric vehicle chargers being contemplated as part of a home electrification project, replacing them with panels able to handle the job can add thousands of dollars and weeks to months of additional work.

If the wires connecting the utility grid to the house need to be upgraded as well as part of this process — which they sometimes do, since household electrical panels are often sized to match utility service — the cost and time involved go up significantly, he said.

Cinnamon estimated average outlays for a homeowner in his Northern California service area: If you’re going to upgrade your electrical service from 100 amps to 200 amps, and the wires are above ground, it’s maybe $5,000 to $10,000” to buy and install a new electrical panel, get an electrical permit from the city, and coordinate with the local utility, he said. It’s three to six months.” If the home is connected via underground power lines, which is typical for more modern and urban homes, it’s $25,000 to dig up the street and put that in, and it takes a year.”

Cost and time estimates can be lower in other parts of the country. Nate Adams, a well-known home electrification contractor and adviser, said that upgrading a 100-amp circuit panel to a 200-amp panel, one capable of powering cold-climate home electrification projects like those he carries out in the Midwest, can cost between $3,000 and $6,000. Pecan Street, an Austin, Texas–based nonprofit research organization, comes in with a lower estimate of $1,000 to $5,000 for a panel upgrade without a utility service upgrade, which it said could take several weeks to complete.

Whatever the local details, upgrades to electrical panels and utility service can make or break the deal for home electrification projects. Very few homeowners are willing to wait weeks or months to replace broken-down natural-gas-fired furnaces or water heaters with electric heat-pump models, Cinnamon said. Even those who’ve planned the switch to all-electric well in advance may balk at the time and costs involved.

This is a major problem for the 48 million homes that a recent Pecan Street report estimated lack sufficient electrical service to go all-electric. At an average cost of $2,000 per upgrade, that adds up to as much as a $100 billion impediment to residential electrification in America,” the report states — and $2,000 per home is at the low end of estimates.

That’s why a number of all-electric home contractors are looking to new technologies from startups and major electric equipment manufacturers that can help solve these electrical panel bottlenecks. The options range from relatively simple circuit-sharing plugs that can safely split the demands of major electrical loads, to fully digital electrical panels and circuit breakers that offer Wi-Fi connectivity and active control over EV chargers, batteries and other key electric assets.

Simple circuit-switching devices to keep big loads in check

One such tool is the SimpleSwitch, a hard-wired circuit-sharing plug” that connects two separate loads — an EV charger and a heat pump, for example — into one 240-volt circuit. It then prevents both loads from simultaneously drawing power.

The Sacramento Municipal Utility District, the public utility serving California’s state capital and surrounding area, is promoting the use of SimpleSwitch devices by its customers. As an electric-only utility, SMUD has been designing rate structures and offering incentives and rebates to shift customers to all-electric appliances and heating systems to help reduce carbon emissions.

That saves money for both customers and the utility. SMUD estimates that it costs the utility $4,725 on average to replace electrical panels and add circuits for customers that are part of its low-income electrification program, and up to $9,000 for retrofits featuring underground distribution lines or other complications.

Sean Armstrong, managing principal of California-based all-electric home developer Redwood Energy, describes SimpleSwitch and similar devices designed to support EV chargers, such as NeoCharge, Dryer Buddy and Splitvolt, as the equivalent of a household power strip for 240-volt devices. They allow more loads to be connected at the home than would otherwise be supportable by the existing electrical panel.

While the SimpleSwitch is hard-wired to keep one primary load on and shut down a secondary load when it exceeds the circuit’s capacity, other devices come with software controls that can be programmed to favor one load over the other based on variables such as relative load share or time of day or week. These devices cost a few hundred dollars — far less than the few thousand dollars that might be needed to replace a panel. Redwood Energy’s pocket guide to all-electric retrofits shows a few of the options.

A chart of circuit-splitting devices from Neo Charge, BSA Electronics, SimpleSwitch and Splitvolt
(Redwood Energy)

Whether these types of circuit-sharing plugs can keep the loads in an electrification project low enough to avoid the need for a panel upgrade depends on the kind of work that’s being done, Armstrong said. The National Electrical Code, which governs electrical work in all 50 states, requires electrical panels to be sized to support the maximum simultaneous draw of every load connected to them, but it primarily applies to hard-wired” systems that don’t plug into outlets.

If you’re doing retrofits, these plug-in devices are pretty standard,” Armstrong said. But there are different standards for new construction than for retrofit projects. 

Smart electrical panels 

There are limits to how far circuit-splitting can get you, however, Cinnamon cautioned. Customers who are combining rooftop solar, a battery, EV charging and other smart electric appliances are likely to need a panel upgrade — and they might want a smart” electrical panel that can help them efficiently manage all of that equipment.

Once rooftop solar comes into the picture, you absolutely, positively need to upgrade to 200 amps,” he said. While that’s not universally the case, it’s a view largely backed up by solar installers and electricians, given that many households installing solar will find themselves exceeding the capacity of smaller panels and may have plans to electrify more household loads and buy EVs.

Adding a battery to a rooftop solar system adds even more complexity, Cinnamon said. Most homeowners buy batteries for backup power during grid outages, but the typical residential battery system doesn’t provide enough energy to power an entire home for an extended period of time. Customers who want to power critical systems like refrigerators, heaters or medical devices need to either actively turn off anything else that might deplete the battery or hard-wire those critical devices separately, a task that requires extra equipment and expensive hours of work by an electrician.

To solve this problem, a new class of smart electrical panels and similar devices have come onto the market over the past few years. Two of the country’s biggest electrical panel manufacturers, Schneider Electric and Eaton, have unveiled such products: Schneider’s Square D panel has digital controls embedded into the panel itself, while Eaton’s embeds them into the circuit breakers within the panel. Armstrong also mentioned Canadian company Koben’s Genius smart panel, which Redwood Energy is studying for its potential to put plugged-in EVs to use in supporting household loads during power outages.

San Francisco–based smart electrical panel startup Span is pursuing a similar path with Sunrun, the country’s leading residential solar installer. In October, the two companies announced a partnership to use Span’s panels in select markets to give Sunrun customers the ability to choose which household circuits are powered by solar, battery or grid power. The Span panels are cloud-connected via Wi-Fi, so owners can control them with a web and mobile app.

An exploded diagram of a Span smart electrical panel

The same day that partnership was announced, Span also launched a Level 2 EV charger that can coordinate with its panel to balance power usage from other circuits. The announcement didn’t cite any specific plans for Sunrun to use the Span charger. But Sunrun is the preferred installer for the equipment to allow Ford’s new F-150 Lightning electric pickup truck to serve as a backup power source for homes.

The path to electrification was going to be stymied by the need for infrastructure upgrades at the utility level,” Span CEO Arch Rao, who formerly led Tesla’s energy storage business, told Canary Media in a November interview. We’re unblocking that.” While the company is still in the early days of deployment, Rao sees the potential for utilities to consider a Span panel’s load controls as a substitute for utility service upgrades, since we can ensure that all the devices aren’t coincidentally turned on at the same time.”

In the same interview, Sunrun CEO Mary Powell highlighted the role that Span’s electrical panels can play in broader household electrification. With the smart panels, it’s easy to strategically electrify your home transportation, your home heating, your home cooking,” she said. There are many homes now where a block to even going to solar and storage is the main panel upgrade. This is a much more effective way to solve that challenge.”

It bears pointing out that Span panels and similar smart products do come at a price that’s quite a bit higher than standard electrical panels. The question for homeowners and installers is whether a smart panel is a cost-effective trade-off. Is it worth the price premium to potentially avoid either the need for expensive and lengthy utility service upgrades or the need to buy and install additional equipment to support solar and battery systems such as automated transfer switches and isolation transformers?

Sub-panels, circuit breakers and edge modules” 

Sub-panel devices that can be installed between a main electrical panel and newly installed loads can serve some of the same functions as smart electrical panels — and at a lower cost. One example is from Lumin, a Charlottesville, Virginia–based maker of subpanels that are used by solar contractors and home battery companies including sonnen and SimpliPhi.

Late last year, Lumin announced the development of its Lumin Edge product line. It’s designed to reduce costs by distributing circuit control across a home. It combines a central control hub that connects to household Wi-Fi with a set of edge modules” that an electrician can install on key circuits in a building. It’s set for commercial launch later this year, Lumin CEO Alex Bazhinov said in a December interview.

Two small, white circuit-control devices and a smartphone displaying the app used to configure them

Installers would love to have something flexible that caters to individual needs,” Bazhinov explained. If they’re doing something in an apartment building or a small home, they may only have a handful of large appliances that they really want to control, to manage in conjunction with solar and a battery.” Lumin is targeting a price of $200 for its hub device and $60 to $80 per edge device to lower the cost of that targeted control.

Eaton, one of the world’s biggest electrical-panel makers, has taken a similar tack on individual circuit control, but it’s installed in a different location. The company’s smart circuit breakers can replace standard analog circuit breakers in Eaton electrical panels, giving homeowners and contractors the option of remotely controlling key circuits for larger loads and collecting data on them.

If you’re upgrading your home and adding new resources, you can use these breakers to support what we call flexible load management,’” Paul Ryan, product line manager for Eaton’s connected solutions business, said in an interview this month. These digital circuit breakers can be programmed to switch between essential and nonessential loads for backup batteries during power outages or turn appliances on and off to shift household electricity use.

Eaton electrical panel with smart circuit breakers and man with smartphone control app
Eaton’s smart circuit breakers are housed right in the electrical panel and can be controlled via smartphone app. (Eaton)

Eaton has also designed a circuit breaker that provides all the functionality of an EV charger, Ryan said, including the ability to take commands from customers, utilities or EVs themselves to shift charging away from times when the grid is under stress and toward times when electricity prices are lower. Other providers of smart circuit breakers such as Atom Power are looking at EV charging as an expanding market.

Bridging the divide between homes and the utility 

Eaton’s smart circuit breakers can be used to manage household power for the benefit of the grid as well as the homeowner. California utility Pacific Gas & Electric, for instance, is running a 100-home pilot project using the company’s smart circuit breakers with batteries from LG Chem and distributed battery controls from startup Sunverge.

Utilities have spent the past decade testing home energy control devices as a way to help customers respond to price variations or signals that encourage them to shift power use in ways that help reduce peak grid demand. A range of virtual power plant” projects are tapping solar-charged batteries, smart thermostats, EV chargers and other household loads for these purposes.

What makes Eaton very interesting — and why we picked them as one of the first [companies] we want to play with — is that Eaton already has 40 to 50 percent of the U.S. market when it comes to circuit breakers” and electrical panels, Sunverge CEO Martin Milani said in a January interview. You can plug and play. If you have an existing Eaton panel already, you can take the analog circuit breaker out and put a digital one in, without any additional wiring.” So even though Eaton’s digital circuit breakers cost more than analog ones do, a customer could avoid the greater cost of having to replace the whole electrical panel.

This system with smart breakers inside the electrical panel may also provide more reliable load control than systems that rely on household Wi-Fi networks to turn major loads on and off. This level of reliability is a major concern for utilities seeking more precise data on just how much load-shifting they’re getting out of their pricing signals or emergency power-down commands.

What’s the utility’s role in smart home electrification? 

There’s an interesting connection between utility load-control projects like these and the challenges of upgrading utility service to handle increasingly electrified homes, according to Russell Unger, a principal with nonprofit think tank RMI’s building electrification initiative. (Canary Media is an independent affiliate of RMI.) If utilities can reap the benefits of home circuit control to avoid expensive and time-consuming service upgrades, should they incentivize it as an alternative to beefing up their grid infrastructure?

The divide between utilities and homes has traditionally been set at the electrical meter. But why not your circuit panel in your house? Why not the equipment in your house or in individual apartments? The delineation is not completely obvious,” he said.

Brian Stewart, a former vice president of sustainability at footwear giant Nike who co-founded the electrification advocacy and education group Electrify Now, highlighted that many home electrification projects can be delayed or rendered impractical by the lack of adequate utility grid service. Convincing utilities to subsidize, or perhaps even actively own, in-home systems that can reduce those barriers makes as much sense as the standard utility practice of paying to build out new grid infrastructure to serve newly built homes, he argued.

Customers who are installing heat pumps and EV chargers will use more electricity,” he said. It makes sense for the utility to help cover some of the upfront costs to upgrade their home electrical systems since they will recoup those costs in long-term electricity sales.”

Homeowners and utilities alike stand to benefit from this new range of products that can augment or replace electrical panels. Expect the offerings to continue to grow — and the discussions about who should pay for them to really take off. It’s a question of whether or not the regulators recognize it and create the policies to make it happen,” Anderson said. 

Jeff St. John is director of news and special projects at Canary Media. He covers innovative grid technologies, rooftop solar and batteries, clean hydrogen, EV charging and more.