Electric-vehicle charging stations are becoming more powerful in order to serve the next generation of plug-in cars, outfitted with bigger batteries that allow them to travel longer distances. Widespread availability of affordable, long-range EVs, coupled with convenient charging options, is considered essential if these vehicles are to reach mainstream consumers.

The problem is that high-powered fast chargers put a strain on the electric grid, which can be difficult for a utility to manage and hit EV customers with high rates.

Enter the Bay Area startup FreeWire Technologies.

FreeWire offers mobile distributed energy systems that are roughly the size of a washing machine and packed with second-life EV batteries. The benefit of using second-life batteries is that they’re more affordable than new ones, while still high-performing. Lithium-ion battery costs have dropped precipitously in recent years, but CEO Arcady Sosinov maintains that the used EV batteries in FreeWire’s Mobi systems are still six times cheaper.

The startup is gaining traction as an alternative to diesel generators with its Mobi Gen product line, and as a concierge EV-charging solution with its Mobi Charger series. With the advent of faster charging systems, FreeWire has found another business opportunity -- and attracted the attention of a large European utility.

Battery-backed EV charging is becoming an important part of the electrification discussion as charging speeds accelerate past 50 kilowatts, to 150 kilowatts, to 350 kilowatts and beyond. Earlier this year, ChargePoint announced it would soon begin offering a 400-kilowatt charging system, which is the most high-powered charging system announced by a manufacturer to date. Today’s mainstream EVs are unable to handle that rate of charge, but the new Tesla Model 3 and Porsche Mission E are expected to be able to.

If two Tesla Model 3s plug in at the same time, in the same place, it would throw 800 kilowatts onto the grid in instant. Now, imagine there are 10 Model 3s looking to fast-charge at the same time -- “It’s a huge, huge spike,” said Sosinov.

“It’s a problem that has sort of been dropped in utilities’ laps by the auto manufacturers, who are pushing for the higher [fast-charging] standards,” he said. “We realized this, and we realized our solution looks better and better as the charging speeds go up.”

FreeWire’s battery-backed fast-charging solution pulls power from a regular 120- or 240-volt outlet, into the second-life battery system, in a slow and steady manner and at times when there’s a surplus of electricity generation. The battery system can then deploy quick-charging up to 50 kilowatts when an EV needs to plug in, insulating the grid from the spike.

“It really becomes a problem of...probability and statistics -- how many cars will come to your charging station, versus how much capacity do you have in your battery, versus what's the input charging speed?” said Sosinov.

FreeWire has already cracked the code for a 50-kilowatt charging system, which can add roughly 200 miles of electric range in an hour. The startup is now striving to deliver faster charging speeds in partnership with the Italian energy multinational Enel.

This summer, the European utility company signed a memorandum of understanding with FreeWire to use the startup’s Mobi Chargers as part of its e-mobility research center. Enel will work with FreeWire to adapt the product to the European market, and explore integration with power conversion systems developed by the utility. The goal is to scale the Mobi’s power delivery to 350 kilowatts in order to serve longer-range EVs.

In Italy, Enel is on the leading edge of recharging infrastructure development and deployment, having recently been awarded EU tenders to build 180 recharging stations of 50 kilowatts and eight high-power recharging stations of up to 350 kilowatts.

The FreeWire agreement “is another piece in the jigsaw of our strategy of 'open innovation' for the development of innovative technologies and solutions to increase the competitiveness of technology for electric mobility and transfer it to a mass market,” said Federico Caleno, head of e-mobility solutions at Enel, in a statement.

“I personally believe that the only way to get charging speeds up to 350 kilowatts is with some sort of buffering solution like ours,” said Sosinov. “Just laying down copper underground is not the smart solution on how to do this.”

Even at 50 kilowatts, the Mobi offers a compelling value proposition for EV fast-charging, he said. Take Uber’s use case, for example. The mobility company wanted to install fast-charging stations for its autonomous electric-vehicle fleet in San Francisco, but it was going to take a year and a lot of money to build out all of the wiring necessary, said Sosinov. By purchasing FreeWire’s Mobi Charger, Uber avoided the expensive infrastructure upgrades by using the battery as an intermediary between the vehicles and the grid.

The Mobi also helps to control charging costs. In the U.S., companies and other organizations that offer public or workplace fast-charging often get hit with high demand charges when EVs plug in, due to the spike in electricity usage. A recent report by the Rocky Mountain Institute concluded that utility demand charges virtually eliminate the business case for public EV fast-charging networks. FreeWire’s battery-backed charging system mitigates the demand spike to reduce or eliminate the demand charge.

Not all countries have these charges. “But whether or not they have incentive structures or penalty structures -- as some would say for demand charges -- the grid still feels it,” Sosinov said. “The grid still sees spikes that happen, and this is a way to smooth that out.”

With the FreeWire Mobi Charger system, a utility can request a predictable power draw of, say, 7 kilowatts. FreeWire’s software system then pulls 7 kilowatts on a continuous basis, topping off the second-life battery pack continuously. When a car comes and grabs energy at the 50-kilowatt rate, the battery depletes and the utility doesn’t feel a thing. Sosinov believes this feature will play a critical role as 350-kilowatt and even 400-kilowatt fast chargers come to market.

In addition to battery-backed rapid recharging, Enel and FreeWire will explore how mobile storage systems can be used to support the distribution network in order to improve resilience, as well as how the systems can be employed during maintenance operations and emergency situations by using the Freewire AMP software platform that allows for remote control of the Mobi fleet.

As the Enel partnership gets underway, FreeWire is also in discussions to deploy its EV fast-charging solution with utilities in California and the U.K.

Earlier this month, the startup brought on board Forrest North, founder of PlugShare, founder and CEO of Mission Motors, and an early employee at Tesla, to serve as vice president of systems integration.

To support growth across all of the company’s lines of business, FreeWire recently secured Stanley Ventures as the lead investor in its $10.5 million Series A round, which is expected to close in the coming weeks.

“We've chosen to partner with Stanley because they've done this before, having pioneered a transition to electrified power tools decades ago. Together, we believe in a rapid and systematic shift to electrification,” said Sosinov. “Similar to what's happening in automotive, we see a similar story playing out in the markets that Stanley operates in. Fossil fuels have been, and still are, the de facto standard in industrial applications, but FreeWire believes that will no longer be true going forward.”