How Redwood is delivering energy faster and cheaper

Today EV batteries can live two lives. First, powering a vehicle. Then, powering today's industrial energy demands. The idea of connecting a repurposed EV battery to the grid may sound like a simple and straightforward solution, but the ability to offer power to the companies who need it today quickly, cost-effectively and with the durability needed, requires a purpose-built hardware and software architecture surrounding that battery. And this is just what Redwood has built.

We sat down with Redwood CTO, Colin Campbell, to learn about how Redwood's materials business fed into the work the company has done to build an energy ecosystem truly offering the Speed to Power solution it seems everyone is chasing to meet the growing demands for energy.

Redwood started as a battery recycling company. What led the company to expand into storage?

We've always been a battery company. We handle huge volumes of battery material, from small consumer products such as cell phones, electric toothbrushes, e-bike and scooter batteries, all the way to large format electric vehicle packs. The idea of building an energy business came from watching perfectly good EV packs go into our recycling equipment and wondering if we could figure out a way to reuse these batteries that have a ton of useful life left.

Our recycling business instilled in us a deep distaste for throwing away anything useful, and the energy business is the same instinct applied one step further upstream. We were recycling perfectly useful energy storage capacity!

Since we were already collecting EV batteries at scale, and knowing we had leaders who could develop the power electronics to deploy those packs cheaply, it felt almost inevitable to build a second life for these batteries.

Repurposed EV batteries have been discussed as a major opportunity for years. What's changed to make this a significant commercial business now?

The demand for energy has accelerated over the last few years. AI data centers, domestic manufacturing, electrification of transportation, and industry are all straining the grid simultaneously. Companies are looking for energy, and smart storage capability, and they need it now.

At the same time, the electric vehicle industry in the U.S. is just now old enough that we're receiving many GWh of used packs every year - enough to make a real impact on the nation's energy storage demand.

That convergence of surging demand meeting a growing domestic supply is what we've been building toward since 2017. Redwood became the largest battery recycler in North America, and the infrastructure we built lets us deploy gigawatt-hours of that supply to support the grid directly.

What happens when a used EV battery arrives at Redwood? How do you know whether the battery should be recycled or repurposed for stationary storage?

Our internal power electronics teams built a tool that runs each pack through a short boot camp, so we can assess remaining capacity and electrical health really swiftly - this takes just a few minutes. While that's happening, we give the pack a thorough physical inspection.

Packs that have sufficient capacity and meet our safety thresholds, go into energy storage. Packs that don't, go directly into recycling and materials recovery.

What are the biggest technical challenges in building commercial energy storage systems from retired EV batteries?

The hardest part is that there's so many different kinds! More than 100 different electric cars are driving around in the U.S., each with different pack chemistry, architecture, voltage, and controls software. We have to use every one simply, quickly, and cheaply.

To do that, we built the Pack Manager. Custom Redwood power electronics that acts as a universal translator for any EV battery pack, regardless of manufacturer, voltage, or chemistry. This one device is how we scale across the variety of packs available today and the packs that will enter the fleet in the years ahead.

Our team brings deep expertise across automotive battery systems, power electronics, and energy - engineers who understand both what these packs were designed to do in a vehicle and what it takes to make them perform reliably as stationary infrastructure. Building a system that can seamlessly integrate a GM pack alongside a Rivian pack alongside something else entirely, and guarantee performance across all of them, is genuinely hard. It's where some of the toughest, and frankly most fun, engineering work in this business lives.

What can Redwood do that a utility, an inverter company, or a big storage developer can't?

There's no other company that builds as much of the power stack as Redwood. No other energy storage company is acquiring batteries, integrating them safely, manufacturing key power electronics, writing the control software living on those power electronics, designing the site itself (e.g. roads, grading, LV and MV transmission lines), optimally sizing the storage (and sometimes solar and generators), integrating diverse resources like solar and turbines, operating it as a power plant with in-house economic optimization software, and writing and running the software that operates it. You might see a company that specializes in one step in this stack, or maybe two, but not all of them.

We can do this because we're great systems and full stack engineers. Being able to zoom all the way out to the site level and all the way into the power electronics, or the battery chemistry, or battery thermals, and move between all of those views fluidly gives us a unique and incredibly valuable ability to pull cost out of the site and move fast.

One specific example: on one of our recent solar plus storage off-grid sites, we are DC coupling the solar to the storage using a unique-to-Redwood arrangement of our Pack Manager. This configuration pulls out 90 percent of the transformers and inverters that would be in a traditional AC-coupled solar site. That's quite literally speed to power.

Everyone is talking about AI-related power demand. Why are repurposed batteries promising for this use case?

Data centers need a lot of power, and they need it now. The grid can't add capacity fast enough, and just getting a new grid connection can take two to four years. So many developers have stopped waiting and started building power on site.

That's where we fit. The batteries already exist, they're already here in the U.S., and they're cheap. Our first system was a12 MW / 63 MWh microgrid powering an AI data center for Crusoe. We went from idea to operating it in months, and it's run at >99% availability since launch. Crusoe has increased their compute power draw on that campus by 7x over that time!

It's not just data centers. Rivian and GM are also partners. Both manufacturers see value in offsetting electricity costs, reducing demand charges, and improving energy resilience for operations that run around the clock. Same idea: lots of power, reliable, and faster than the grid can deliver it.

Where is Redwood headed from here?

We'll keep moving up the stack. We started with very cheap, utility-scale storage. Then we paired that storage with solar to make clean firm power: cheap, fast, and there around the clock, not just when the sun's out.

Now we're getting closer to the data center itself. We know how to build chemical plants, and the cooling and power architecture of a data center is simple compared to a hydromet refinery. Every time we take on more of the stack and engineer it as one system, it gets cheaper to build, and the market gets bigger.