Solar-battery systems may be useful for providing backup power during power outages. But many of the systems on the market today don’t pack enough punch to start up power-hungry air conditioner or pumps, or store enough power to run an entire home’s electricity load for more than a handful of hours at a time. 

That’s how Generac Power Systems sees it, at least. Since its entry into the solar-storage market last fall, the U.S. natural-gas backup generator giant has focused on systems with extra oomph, compared to competitors Tesla, Sunrun and LG Chem. While that extra power and capacity has come at a higher cost, Generac has been dropping prices to match competing systems in recent months, analysts say. 

On Monday, Generac unveiled the latest version of its “whole-home solar power solution," which includes a revamped PWRCell battery with more power and capacity than before, along with technology to simplify its off-grid operations and maximize its backup potential at the household circuit level.

Managing backup power at the circuit level

“There’s a gap between what the customers want and what they’re being delivered” in the solar-storage field, Russ Minick, head of Generac’s clean energy business unit, said in an interview. A typical installation requires significant work to rewire critical loads and replace household electrical panels to provide reliable backup power, which can add several thousand dollars to the final price. 

The new PWRCell automatic transfer switch, set for release in late August, eliminates much of this work for installers. “Whatever they’re doing today for whole-home backup power, it will cut back enormously on labor costs [and] on total expense,” Minick said. 

Besides disconnecting from the grid during power outages, the automatic transfer switch can manage up to four household circuits, and smart management modules can be installed on up to eight more. The hardware monitors power frequency to shut down loads when the total draw is exceeding system capacity, with the homeowner pre-selecting which should shut down first and which should be kept on as long as possible. 

That’s a simpler proposition for installers compared to “worrying about doing load calculations and tripping breakers,” Minick said. Other unessential loads can be “locked out” from being backed up. That stands in contrast to pre-selecting critical backup loads for other solar-battery systems, as most solar-battery systems do today. 

There are more advanced options for circuit-by-circuit controls, such as startup Span.IO’s smart home electrical panel, or the ecoLinx system from sonnen using smart circuit breakers from Eaton. But those are more expensive than Generac’s solution, Minick said.  

Extra power for critical loads

Waukesha, Wisconsin-based Generac has also beefed up its PWRCell inverters, also set for release in late August, from 8 kilowatts of continuous power today to 9 kilowatts from a single battery or up to 11 kilowatts with a second battery. That compares to 5 kilowatts of continuous power from Tesla’s Powerwall and Sunrun’s Brightbox, or 3.5 kilowatts of continuous power from LG Chem’s Resu battery. 

That’s a key metric for how much household load a backup battery can power simultaneously. As Greentech Media noted last year, most systems are configured to support fewer loads to ensure they can be kept running as long as possible. 

Along with greater power density, the new inverters can provide up to 50 amps of peak motor starting current, up from 42 amps today. That’s enough to start up a 3-ton air conditioning unit or a well pump, something lower-power inverters can’t do, although contenders like Enphase Energy, which is bringing its own battery solution to North American market this year, has software to boost its ability to start up AC and pump motors. 

Generac has also redesigned the battery modules developed by Pika Energy, the Massachusetts-based startup it acquired last year to enter the storage market, to boost their storage capacity from 17.1 kilowatt-hours to 18 kilowatt-hours per battery, or 36 kilowatt-hours behind a single inverter. Enhanced cooling via silicon pads conducting heat to aluminum heat sinks will also allow the batteries to be installed in outdoor enclosures when they’re available in early October. 

The entire system is managed through software from Vancouver, Canada-based startup Neurio, which Generac acquired last year. “It’s going to tell you production, consumption — you can set energy budgets and bills, it will show you if there are 'vampire' loads, how you compare against a peer group, are you using more than your neighbors,” Minick said. 

From backup generators to virtual power plants

Whether these changes will allow a relative newcomer to make inroads against well-established competitors such as Sunrun and Tesla, or residential solar inverter leaders with storage plans such as SolarEdge and Enphase, remains to be seen. Beyond using its existing network of generator dealers, Generac partnered with Sunnova, a rising residential solar provider, in February as its exclusive lease and power-purchase agreement provider to tap into this key avenue for solar-storage sales. 

Generac set a goal of 125 to 150 megawatt-hours of battery sales this year, although CEO Aaron Jagdfeld noted during the company’s second-quarter earnings conference call last month that solar installations slowdowns driven by the COVID-19 pandemic are expected to yield 2020 totals on the lower end of that guidance. 

For long-term power outages, generators fed by natural-gas lines, which aren’t nearly as susceptible to storm-driven outages as the electric system is, are still a better bet for backup power, Minick told Greentech Media last year. On the other hand, solar-storage systems designed primarily to shift generation and load to increase net-metering value against time-of-use pricing may not need the extra battery capacity and power that Generac provides. 

But the combination of increasingly favorable economics of solar and batteries and the rising need for protection from storms, wildfires and other grid supply disruptions is putting backup power at the forefront of many customers’ minds, he said. 

At the same time, Generac’s new solar-storage systems could be combined with its massive installed base of generators to become a significant resource for the grid itself, much as Sunrun has been doing with its solar-storage systems. The company’s partnership with Virtual Peaker, a software startup aggregating behind-the-meter distributed energy resources for utilities including Portland General Electric and Green Mountain Power, opens up new opportunities on this front, Jagdfeld said last month. 

“In the clean energy space, most people have been considering these blocks of load to be storage items or wind power or other clean sources,” Jagdfeld said. “We look at natural-gas generators, which in their own right, are quite clean.”