Moxion Power and the Future of Mobile Battery Storage

The Story of Moxion

On a hiking trail in Mill Valley, California, during the devastating 2019 fire season, two entrepreneurs stumbled upon a diesel generator churning away. It was powering critical water infrastructure while much of their town relied on similar units for grocery stores, coffee shops, and essential services. The acrid smell of diesel exhaust mixed with smoke-filled air crystallized a simple question: "Isn't there a better way to deliver temporary power?"

That question sparked the creation of Moxion Power, a company that would raise over $110 million, deliver 400+ battery units, attract investments from Amazon and Microsoft, secure a partnership with one of America's largest equipment rental companies, and host California Governor Gavin Newsom at its factory launch - before collapsing spectacularly in July 2024.

The story of Moxion Power is more than a tale of startup failure. It's a complex case study in climate tech scaling, market timing, and the brutal economics of hardware manufacturing. And remarkably, it's a story that didn't end with bankruptcy. Today, as Viridi Parente has moved into Moxion's former facility with fresh capital and lessons learned, the mobile battery storage market faces a critical question: Was Moxion too early, or was the business model fundamentally flawed?

The Early Startup Days

Paul Huelskamp and Alex Meek, the hiking partners who conceived Moxion during the 2019 fires, weren't naive entrepreneurs. Huelskamp brought more than 15 years of experience as a private equity professional in renewable energy, having been part of founding teams at EverStream Yield (which went public as Terraform Power) and White River Solar. Meek had founded Newday, an asset management firm overseeing $175 million. Together with co-founders Alex Smith (an experienced battery engineer from NIO and LG Chem) and Jed Mickle, they formed Moxion Power in 2020.

The founding team understood the market opportunity intimately. Diesel generators have long dominated temporary power for construction sites, live events, film production, disaster response, and defense applications. But these workhorses come with significant drawbacks: constant noise pollution, maintenance headaches, fuel logistics, and—most critically in California's regulatory environment—millions of tons of greenhouse gas emissions annually. In California's South Coast and Bay Area alone, diesel generators emit 20 tons of fine particulate matter, 62 tons of volatile organic compounds, and nearly 1,000 tons of nitrogen oxide each year.

Moxion's thesis was elegant: create a portable battery powerful enough to replace diesel generators, offering 75 kilowatts of power and over 600 kilowatt-hours of energy. The units would be silent, zero-emission, and when charged from renewable sources, truly clean. They could be swapped when depleted, turning the traditional generator rental model into a battery-as-a-service business.

The idea gained immediate traction. In 2021, Moxion joined Y Combinator's winter cohort—a prestigious accelerator that typically focuses on software but saw potential in this hardware-heavy climate tech play.

The Meteoric Rise: $100 Million and Governor's Approval

By September 2022, just two years after founding, Moxion had achieved what many climate tech startups only dream of: a massive $100 million Series B round led by Tamarack Global. The round included participation from Energy Impact Partners (their Series A lead), and strategic investments from major corporations including Sunbelt Rentals, Amazon's Climate Pledge Fund, Microsoft's Climate Innovation Fund, Enterprise Holdings Ventures, Marubeni Ventures, and Suffolk Technologies.

Sunbelt Rentals' involvement was particularly significant. As one of the country's largest equipment rental companies with a massive fleet of diesel and gasoline generators serving construction sites, film locations, and concert festivals nationwide, Sunbelt's dual role as investor and customer seemed to validate both the product and the market opportunity. If the experts in temporary power rental saw the future in batteries, conventional wisdom suggested, surely the market was ready.

The validation continued throughout 2023. According to a LinkedIn post from a former manufacturing engineering manager, Moxion successfully delivered over 400 first-generation units that year. The company held a launch ceremony for a new manufacturing plant with 7 gigawatt-hours of planned capacity, attended by California Governor Gavin Newsom, a powerful signal of government support for domestic clean energy manufacturing.

Moxion was on a hiring spree, growing to over 400 employees. Many came from prestigious tech and automotive companies including Tesla, Proterra, and Uber. The company outgrew its original Mill Valley headquarters and in January 2024 signed a lease for a massive 100,000-square-foot expansion in Richmond, California. According to one co-founder's profile, the company delivered over $100 million in revenue in its first year.

For those in Bay Area CleanTech circles, Moxion had become "the company you want to work for," according to a former senior manager who spoke to reporters after the collapse.

The Cracks Appear: Growth Without Validation

But beneath the surface of this success story, critical problems were emerging - problems that would ultimately prove fatal.

According to multiple insiders who spoke to the press after the bankruptcy, Moxion's leadership made a crucial strategic error: they "anticipated the market demand too early, without much validation." The company scaled production and headcount aggressively based on the confidence that if Sunbelt, which understood the generator rental market better than anyone, was placing multi-million-dollar orders, the product must be ready to scale.

"They know [the market] much better than we do, so let's just trust them and just go and start building," summarized one former senior manager describing leadership's mindset.

This approach led to what insiders described as "rapid growth" that the company couldn't properly manage. The hiring of several hundred people and the commitment to massive new manufacturing capacity happened before the company had fully resolved technical issues with their first-generation product.

Technical Problems at Scale

The rapid scaling meant that "silly little mistakes" became expensive to fix. One critical oversight: the first-generation batteries lacked bidirectional charging capability, meaning they couldn't charge and discharge simultaneously. While this might seem like a minor technical detail, it fundamentally changed the user experience. Customers accustomed to the straightforward operation of diesel generators—which can run continuously while being refueled—found the Moxion units less convenient, leading to lower utilization rates.

Making updates to fix such hardware problems became both expensive and logistically difficult once hundreds of units were already in the field and the company had committed to large-scale production. The company planned to begin production of an improved second-generation unit by the end of 2024, but that timeline proved overly optimistic.

Market Fit Challenges for Mobile Storage

Beyond technical issues, evidence emerged that Moxion may have been targeting the wrong segment of the market. Neel Vasavada, founder of Overdrive Energy Solutions (itself a competitor using portable batteries for live events), had rented 41 Moxion units over eight months and found them excellent for his needs. His clients were happy and increasing their use, making the business profitable despite rental costs.

But Vasavada believed Moxion's fundamental strategic error was thinking they could successfully sell to diesel generator rental companies at scale. While companies like Sunbelt might rent out some battery systems, "none of them are deploying these battery systems in any meaningful volumes," he observed.

The live events market - where Moxion eventually dabbled by powering a festival in Mill Valley in May 2024 - might have been a better fit despite being smaller. Live events increasingly prioritize decarbonization, and the silent, emission-free nature of batteries offers unique value for concerts, festivals, and film production where noise and air quality matter. Amazon Studios had even invested in Moxion specifically for batteries to power film and television sets.

But by the time these market dynamics became clear, Moxion was already committed to a scale and cost structure that required massive volume in the construction and generator rental markets.

The Collapse of Moxion

In February 2024, Bloomberg Law reported that Moxion was attempting to raise a new equity round of $200 million at a $1.5 billion valuation. But the timing couldn't have been worse. The company was seeking capital amid what analysts called "a shakeout in the climate tech market" throughout 2024, with numerous high-profile climate startups struggling to raise follow-on funding as investors became more cautious about hardware-heavy cleantech businesses.

The first public signs of trouble came in June 2024, when Moxion laid off 101 employees in what appeared to be a cost-cutting measure. It was a sharp reversal for a company that had seemed unstoppable just months earlier.

On July 19, 2024, Moxion furloughed most of its remaining staff—a total of 248 employees according to a WARN notice filed with California. The notice, required for mass layoffs, indicated the company "was not able to raise more capital" despite efforts to do so.

Just one week later, on July 26, CEO Paul Huelskamp sent the email that ended it all: "I'm writing to you this morning with a heavy heart. We have not found a path that will allow us to continue operations as Moxion Power Co., and effective today, we will be closing our doors."

The shutdown was immediate and brutal. According to the company's messaging, funding negotiations had fallen through at the last minute, creating an "unexpected and last-minute shortfall" that made it impossible to provide any severance to remaining employees. The company sent notices to vendors stating it had put "a hold on payments, including critical vendor payments."

One laid-off employee filed a lawsuit against the company, alleging violations of California's WARN Act for failing to provide adequate notice before the mass layoff and claiming unpaid wages.

The Bankruptcy Filing

On August 12, 2024, Moxion Power filed for Chapter 7 bankruptcy liquidation in Delaware, listing estimated liabilities between $100 million and $500 million. The filing provided a stark picture of the company's financial position:

Assets (totaling $118.2 million):

• $51.7 million in inventory (split between raw materials and finished mobile generators)

• Over 200 mobile power units valued at $140,688 each (totaling $28.7 million)

• Other property and equipment

Liabilities (totaling $86.9 million):

• $33.1 million owed to Silicon Valley Bank (secured by collateral, likely to be paid first)

• Approximately $30 million owed to four Michigan manufacturing companies

• $7.5 million owed to Bay Area battery maker Gotion

• $15,150 priority claims for several Moxion leaders

• Claims from 324 additional businesses (many under $200,000, but 20 owed at least $200,000 each)

• A checking account balance of just $201,980

The bankruptcy filing revealed that Moxion had reported a $28 million net operating loss in 2022, underscoring how the company had been burning through its raised capital without achieving profitability.

For laid-off employees, the collapse was devastating. With no severance and in many cases with unpaid final wages, workers who had left stable positions at companies like Tesla and Uber found themselves suddenly unemployed. The enormous Richmond facility they'd planned to occupy sat incomplete, a physical monument to ambitions that exceeded execution.

Enter Viridi Parente: A Different Approach to the Same Market

As Moxion's assets entered liquidation, a Buffalo, New York-based company called Viridi Parente saw opportunity where others saw failure.

Founded in 2009, Viridi had spent 15 years developing what it calls "fail-safe" battery energy storage systems with a proprietary anti-propagation architecture designed to prevent thermal runaway - a critical safety concern with lithium-ion batteries. Viridi's systems had achieved a significant milestone: becoming the first and only commercial-scale battery energy storage system approved for installation in occupied spaces.

While Moxion focused on mobile batteries for temporary power replacement, Viridi had initially concentrated on behind-the-meter installations for industrial, medical, commercial, and municipal buildings. But the company also had experience with mobile applications, deploying systems for remote mountain races, large sporting events, and music festivals, as well as critical infrastructure during hurricanes Helene and Milton.

Viridi's CEO Jon Williams saw Moxion's collapse not as a failure of the market, but as a validation opportunity. "Moxion vetted out all the issues in the market that we were able to solve for with our unit," Williams told reporters, "and really helped us build a better unit, in honesty."

The Acquisition Deal

On September 27 and October 30, 2024, Viridi completed asset purchase agreements acquiring key Moxion assets for $7 million through the bankruptcy auction. The acquisition included:

• The 40,000+ square-foot production facility in Richmond, California

• Much of Moxion's built inventory of battery units

• Intellectual property and patents

• Equipment and manufacturing capabilities

Critically, Viridi also assumed Moxion's relationship with Sunbelt Rentals, which still had significant numbers of Moxion units deployed in the field. Williams told reporters that Viridi would use the acquired resources to help maintain Sunbelt's existing fleet inventory, a practical necessity since Sunbelt had invested heavily in the units and needed ongoing support.

In fact, Sunbelt deployed several of these hybrid systems during the devastating Los Angeles fires in early 2025, combining Viridi battery systems with diesel generators for locations like command centers, canteens, and bathroom facilities. Several of the units were already in the LA area when emergency calls for temporary power came in.

The $9.3 Million Grant and California Expansion

The acquisition became even more attractive when Viridi secured a $9.3 million grant from the California Energy Commission (CEC) to upgrade and operationalize the facility. This grant, announced in April 2025, marked a major milestone for Viridi's expansion strategy.

"This grant from the CEC is a testament to the urgent need for advancing energy storage solutions that are both safe and scalable," said Williams. "Our expansion to the West Coast represents more than just growth—it's a pivotal step toward transforming California's energy landscape."

The Richmond facility gives Viridi bicoastal manufacturing, R&D, sales, and service operations, expanding from its Buffalo headquarters to California—the fifth-largest economy in the world and a leader in renewable energy policy. Viridi plans to employ 75 people at the California facility.

California Energy Commission Chair David Hochschild emphasized that "Viridi's innovative approach to energy storage aligns with California's commitment to advancing safe, sustainable and resilient energy solutions," while California Air Resources Board Chair Liane Randolph noted that "energy storage plays a vital role in creating cleaner air and healthier communities."

Lessons Learned: Why Viridi Might Succeed Where Moxion Failed

The contrast between Moxion's collapse and Viridi's acquisition offers critical lessons about navigating the mobile battery storage market.

1. Manufacturing Strategy: Build vs. Buy

One of Moxion's fatal decisions was attempting to vertically integrate manufacturing. The company built its own factory, hired hundreds of manufacturing employees, and took on the enormous fixed costs and complexity of battery production in-house.

Paul Huelskamp, Moxion's former CEO, who has since launched a new startup called Anode Technology Company, explicitly identified this as a key lesson: "One of the main lessons learned is it's really tough as a startup to take on that part of [the manufacturing]," he told reporters.

Anode will use contract manufacturers to make its batteries rather than building them in-house—a capital-light approach that dramatically reduces risk and fixed costs.

Viridi, meanwhile, is acquiring an existing facility at a fraction of the cost of building new, with additional grant funding to offset upgrades. By purchasing Moxion's already-built infrastructure for $7 million (plus the $9.3 million CEC grant for improvements), Viridi gets manufacturing capacity without the development risk and at a far lower effective cost than Moxion's original investment.

2. Product Differentiation: Safety as Selling Point

Viridi's core differentiator is its proprietary anti-propagation technology that prevents thermal runaway in lithium-ion batteries. This fail-safe design enables the company's batteries to be installed in occupied spaces—something competing systems cannot do.

This safety positioning matters enormously in a market where battery fires remain a significant concern for potential customers. By prioritizing safety from the ground up, Viridi can access applications that other mobile battery systems cannot, including indoor installations and locations near sensitive infrastructure.

Moxion, by contrast, focused primarily on power density and portability to match diesel generator specifications, but may not have sufficiently differentiated its safety profile in a crowded market where established players are also introducing battery alternatives.

3. Market Focus: Multiple Applications vs. Single Bet

Viridi's strategy includes diverse applications: large-scale, behind-the-meter commercial installations, mobile power for events and construction, emergency response, and increasingly EV charging depots. This diversification reduces dependence on any single market segment.

Moxion appears to have bet heavily on penetrating the construction and generator rental markets—particularly through its partnership with Sunbelt—without fully validating demand at scale in that segment. When that primary market didn't materialize as quickly as projected, the company had limited alternatives.

Neel Vasavada of Overdrive Energy Solutions, who successfully used Moxion batteries for live events, believes Moxion should have focused more on the events market where decarbonization is a higher priority and customers value the silent, emission-free operation more intensely. "The reason why I believe Moxion failed is because they thought that they could sell products to diesel generator rental companies, and find a lot of success," he said.

4. Growth Philosophy: Slow and Validated vs. Fast and Ambitious

Perhaps the most important lesson is philosophical. Moxion's former senior manager summarized it succinctly: "The lesson for me was 'grow slow, grow small.' If the timing works out well, and if you are lucky, you will make it big. Otherwise, you are not the exception."

Moxion grew too fast based on the assumption that Sunbelt's large order validated product-market fit. They hired hundreds of people, signed leases for massive facilities, and ramped production before thoroughly testing and iterating on their technology in real-world deployments.

Viridi, having watched Moxion's trajectory, can now move into a fully built facility, support an existing customer base (Sunbelt), and scale more cautiously based on actual market demand rather than projected demand.

The Market Opportunity: Still Real, Still Growing

Despite Moxion's failure, the fundamental market opportunity for mobile battery storage remains not only viable but growing rapidly.

Market Size and Growth

Multiple market research firms project strong growth for mobile battery energy storage systems:

• The global mobile energy storage system market is projected to grow from $58.28 billion in 2025 to $156.16 billion by 2032, representing a compound annual growth rate (CAGR) of 15.12%

• The more specific mobile battery energy storage system (MBESS) market is projected to reach $391.3 million in 2025 with a CAGR of 9.4% through 2033

• The broader battery energy storage system market is expected to reach $20.22 billion by 2029, growing at 23.9% CAGR

The temporary power market—the immediate addressable market for mobile batteries replacing diesel generators—is estimated at approximately $12 billion in 2021, projected to grow to over $20 billion by 2028, representing nearly 8% CAGR.

Compelling Drivers

Several powerful trends support continued growth in mobile battery storage:

Regulatory Pressure and Emissions Targets

Governments worldwide are implementing increasingly strict emissions regulations. California's aggressive carbon neutrality targets and clean air standards make mobile diesel generators a liability. Europe is following similar paths, with mobile battery systems providing zero-emission alternatives required to meet decarbonization goals.

Total Cost of Ownership Advantages

While battery systems have higher upfront costs than diesel generators, their operational economics are compelling for high-utilization applications:

• Batteries can charge at 3-5 cents per kilowatt-hour from the grid or renewable sources, compared to several dollars per kilowatt-hour effective cost for diesel generators

• Minimal maintenance requirements (no oil changes, engine maintenance, or mechanical repairs)

• Instant on/off capability without engine wear from frequent starts and stops

• No fuel logistics, delivery, or storage costs

• Silent operation enables use in noise-sensitive locations and time periods

For customers who use temporary power frequently—rather than occasional backup needs—the economics strongly favor batteries over time.

Growing Renewable Energy Integration

As the grid becomes increasingly powered by renewable energy, mobile batteries charged from grid power become inherently cleaner. This creates a virtuous cycle: as renewable energy expands, the value proposition of battery systems strengthens.

Some companies are even developing innovative models like charging large battery systems at industrial solar facilities, then deploying them to remote construction sites—enabling truly zero-emission temporary power.

Adjacent Market Growth

The explosion of electric vehicles creates new demand for mobile charging solutions. EV fleet charging depots need substantial temporary power during buildout, and mobile batteries can provide that power without expensive grid upgrades. Companies like Anode (Paul Huelskamp's new venture) are specifically targeting this emerging market.

Data center growth, high-speed rail construction, and increased disaster response needs all create additional demand for flexible, deployable power solutions.

The Verdict: The Opportunity Is Real, But Execution Is Everything

After examining Moxion's rise and fall, Viridi's acquisition, and the current market landscape, a clear picture emerges: the market opportunity for mobile battery storage is genuine and growing, but the business model requires careful execution and realistic expectations.

Why the Opportunity Is Real

The fundamentals supporting mobile battery storage are sound and strengthening:

• Regulatory tailwinds: Emissions regulations will only become stricter, making diesel generators increasingly expensive and restricted

• Economics at scale: For high-utilization customers, batteries already offer better total cost of ownership than diesel

• Technology maturity: Battery costs have fallen 97% over recent decades, making energy storage commercially viable for the first time

• Market size: With 500,000+ diesel generators currently deployed in the US alone, the addressable market is enormous

• Adjacent opportunities: EV charging, data centers, and grid stabilization create new applications beyond simple generator replacement

Multiple companies beyond Viridi are actively pursuing this market, including POWR2 (showcasing mobile BESS at Bauma 2025), established players adding battery options, and numerous startups globally. This sustained interest from diverse players signals genuine market opportunity rather than hype.

Why Execution Determines Success

However, Moxion's failure reveals that opportunity alone doesn't guarantee success. Winners in this market will need:

1. Disciplined Growth: Scale based on validated demand, not projected demand. Resist the temptation to over-hire and over-build based on large initial orders.

2. Product-Market Fit First: Thoroughly test and iterate products in real-world applications before scaling. Identify which customer segments truly value the benefits enough to overcome the higher initial costs.

3. Capital Efficiency: Use contract manufacturing, strategic acquisitions of distressed assets, and grants/incentives to minimize capital intensity. Hardware businesses require different financial models than software startups.

4. Technical Excellence: Safety, reliability, and user experience cannot be compromised. The technology must work as well or better than diesel generators in practice, not just in specifications.

5. Market Segment Focus: Target customers who benefit most from batteries' unique advantages (silence, zero emissions, indoor use) rather than trying to replace all diesel generator applications immediately. Live events, film production, indoor applications, and noise-sensitive construction sites may be better initial markets than general construction.

6. Realistic Timelines: The transition from diesel to batteries will take years or decades, not months. Business models must accommodate longer adoption curves than software products.

The Current State: Cautious Optimism

As of late 2025, the mobile battery storage market appears healthier than it did during Moxion's 2024 collapse. Battery costs continue declining, regulatory pressure continues intensifying, and customer awareness is growing. The $9.3 million California Energy Commission grant to Viridi signals continued government support for the sector.

Viridi's move into Moxion's former facility with support from Sunbelt Rentals suggests the market is learning from past mistakes. By acquiring infrastructure at distressed prices rather than building from scratch, using proven safety technology, and maintaining existing customer relationships, Viridi has a more capital-efficient path than Moxion attempted.

The founder of Anode Technology Company (Paul Huelskamp, Moxion's former CEO) returning to the space with a leaner, contract-manufacturing model indicates that even those who failed see continued opportunity—they're just pursuing it differently.

Meanwhile, a growing ecosystem of companies—from POWR2 to numerous international players showcased at industry events—demonstrates that mobile battery storage is becoming an established category rather than an experimental one.

Conclusion: A Market in Transition

The Moxion Power story is ultimately about the brutal realities of climate tech hardware businesses: massive capital requirements, long development cycles, complex manufacturing challenges, and entrenched competition. Even with over $110 million raised, impressive technology, support from major corporations and governments, and real customer demand, execution missteps proved fatal.

But it's equally a story about market resilience. When Moxion's doors closed, the market didn't disappear. Competitors like Overdrive Energy Solutions continued serving customers profitably. Sunbelt Rentals still needed support for its deployed units. And Viridi saw enough potential to invest $7 million (plus secured grants) in continuing the mission.

For Neel Vasavada of Overdrive Energy Solutions, Moxion's demise was frustrating precisely because the technology worked. "The market for portable renewable power — and even for Moxion's battery specifically — is still very much there," he said. "I can't even get my grubby hands on a unit. It's maddening."

That sentiment—frustration at the loss of working technology rather than skepticism about the market—may be the most telling indicator of all. The opportunity isn't failed; it's still emerging. Companies that learn from Moxion's mistakes while pursuing the validated opportunity have genuine chances of success.

As Viridi's CEO Jon Williams puts it, crediting his predecessor: "Moxion vetted out all the issues in the market that we were able to solve for with our unit, and really helped us build a better unit."

In climate tech, as in many industries, being first doesn't guarantee winning. But being smart, learning from others' mistakes, and executing with discipline? That just might be the formula for turning a failed startup's vision into a thriving market reality.

The mobile battery storage revolution is coming—just more slowly, more carefully, and with more hard-won lessons than the optimists of 2022 imagined. And that might be exactly what it takes to make it sustainable.

Note: Market size projections and financial figures cited in this article are based on publicly available research reports and news coverage as of October 2025. Actual market development may vary from projections.