Axle Energy raises $25m as device makers carry its virtual power plant

On 8 July, Axle Energy announced a $25m (£18.7m) Series A led by Energize Capital, a US investor in energy software, with its existing backers Accel, Picus Capital and Eka Ventures investing again. The London company writes software that connects home batteries, EV chargers, heat pumps and other devices to electricity markets. Pooled together, those devices act as a virtual power plant: they charge when power is plentiful and cut demand or discharge when the grid is short, and their owners are paid for it.

Axle was incorporated on 2 February 2023 by Karl Bach, its chief executive and a former executive at the energy supplier Bulb, and Archy de Berker, a data scientist who is its chief technology officer. Companies House lists both as persons with significant control, each holding between 25% and 50% of the shares. In Accel’s account, the pair spent years working on electricity markets before starting Axle and saw how hard it was for small, scattered devices to take part in the markets that balance the grid. Their pre-seed announcement in June 2023 described the product as software “that makes it trivial to connect domestic assets to electricity markets”.

That round raised $1.6m from Picus and Eka. Accel led a $9m (£6.7m) seed in August 2024, and the Series A takes Axle’s disclosed funding to about $36m. Tyler Lancaster, a partner and co-head of ventures at Energize, was appointed a director of Axle on 21 April 2026, Companies House records show, 11 weeks before the round was made public.

Flexibility from homes has usually reached the market through the energy supplier, which owns the customer, the meter data and the tariff. Axle’s announced partnerships this year go around it. They have been with the manufacturers of inverters and home batteries, which offer Axle’s virtual power plant to their own customers whoever supplies their electricity. Energize is paying to take that route abroad, and it moves the earnings from home flexibility toward the companies that make and run the devices.

Selling through the battery makers

In January, Axle signed up FoxESS, the inverter and storage maker, so that its battery owners could earn “regardless of their energy supplier or tariff”, as the announcement put it. Users were offered £1 per kilowatt-hour for the grid services their batteries provide and a £10 monthly minimum until March 2026, and installers £50 for each customer they referred.

SolaX followed in February with what the two companies called a global partnership, starting in France and Axle’s home market and promoted to SolaX battery owners through a virtual power plant feature in the SolaXCloud app. “By partnering with SolaX, we’re making it easy for households and businesses to play an active role in supporting the grid,” Bach said at the time. Solis, the inverter brand of the Shenzhen-listed Ginlong Technologies, joined in March: owners of compatible hybrid inverters can enroll without changing supplier or switching tariff.

For the manufacturer, the arrangement turns grid payments into a feature it can sell without becoming an energy trader. Axle runs the commercial chain behind it, from connecting the devices and forecasting when they will be available to bidding into markets, dispatching them and settling payments, according to Accel, and shares the revenue with the device makers and their customers.

The founders wrote in their Series A post that device manufacturers, energy suppliers and fleet operators use the platform, and that “dozens of clients” have built consumer offers on it. Energy suppliers remain one of those channels. Accel puts the platform at more than 300,000 connected assets and more than 2GW of flexible capacity, figures that come from the company.

What the Series A pays for

Bach and de Berker said the round would speed Axle’s expansion “into Europe and beyond”. The company estimates there are around 75 million eligible energy assets across Europe and the US, representing roughly 375GW of potential flexible capacity, according to Accel’s investment note. On its own figures, Axle has connected about 0.5% of that today.

“Axle’s goal is to make it trivial for distributed devices to participate in energy markets, wherever in the world they’re deployed,” the founders wrote. The manufacturer partnerships are what make that goal plausible. A battery brand that sells across a dozen countries can carry Axle into each of them through an app update, while a supplier partnership stops at the supplier’s own customer base.

Energize brings a board member from the US side of the market. Lancaster, whose earlier work at Accenture Strategy covered distributed energy resources for electric utilities, also sits on the boards of Patch, Smartcar, Urbint and TWAICE, according to Energize’s website. Zhenya Loginov, a partner at Accel, said in comments published by UKTN that flexibility would become “one of the most important layers of the modern energy stack”.

Who earns from home flexibility

For energy suppliers, the round confirms a competitor for the margin on flexible demand that does not need to win the household’s electricity account. For fleet operators and charger makers, it adds a buyer for capacity they already own. For Axle, the test abroad is whether market rules in each new country let an independent aggregator trade devices directly, as it now can at home.

The $25m is a bet that the virtual power plant will be sold the way connected devices are sold: through the brand on the box, with the energy supplier as one partner among many.