All Aboard Fund I Targets Climate Tech’s “Missing Middle” With $300M Fund

A new funding vehicle has landed in the climate tech space, and it’s an important one.

All Aboard Fund I is seeking to raise $300 million to help climate tech companies move from validated technology to commercial-scale deployment. The fund’s final close is expected on June 30, 2026.

The fund is connected to the broader All Aboard Coalition, a group of leading climate and deep tech investors, including Breakthrough Energy Ventures, Khosla Ventures, DCVC, and Clean Energy Ventures.

The distinction matters: the Coalition member firms are not investors in the Fund. Instead, All Aboard Fund I is designed to co-invest alongside members of the Coalition.

Many climate tech startups have proven their technology but face a major hurdle when moving from pilots to full commercial deployment.

This challenge is often called the “missing middle.” It’s the stage where promising innovation risks stalling because traditional venture investors may see the opportunity as too capital-intensive, while infrastructure financiers may view it as too early.

All Aboard Fund I is built to help close that gap.

What Is All Aboard Fund I?

All Aboard Fund I is a climate-focused investment fund created to support companies that have moved beyond early technical validation and are ready to scale.

Unlike seed-stage climate funds, this vehicle is focused on helping companies cross the difficult stretch between venture-backed innovation and infrastructure-ready deployment.

In simple terms, All Aboard Fund I is positioned to help climate companies move from pilot projects and early commercial traction into broader production and deployment.

Why the “Missing Middle” Matters in Climate Tech

This stage of financing is critical for climate innovation.

Many climate startups can prove their technology in a lab, pilot, or first commercial setting. The harder part comes next: building larger systems, expanding production, or financing the first wave of commercial-scale projects.

Those efforts often require significant capital, patient investors, and sector-specific expertise.

Traditional venture firms can hesitate at this stage because climate hardware and infrastructure-adjacent companies often need more time and capital than software businesses. Infrastructure funds, meanwhile, usually prefer mature assets with predictable revenue.

That leaves a funding gap where too many promising technologies slow down or stall.

Funds like All Aboard Fund I are stepping into that gap, helping later-stage climate technologies become investable, scalable, and commercially viable.

The Role of the All Aboard Coalition

The All Aboard Coalition brings together leading firms across climate, deep tech, and industrial innovation.

Members include Breakthrough Energy Ventures, Khosla Ventures, DCVC, and Clean Energy Ventures.

These firms bring deep experience backing companies across clean energy, advanced manufacturing, carbon removal, climate infrastructure, and industrial decarbonization.

All Aboard Fund I is not backed by these Coalition members as limited partners. Instead, the fund is designed to co-invest alongside them, helping provide additional capital for companies that are ready to move from proven technology to broader deployment.

That structure is important because it connects experienced climate investors with a dedicated financing vehicle aimed at the scale-up gap.

What This Means for Climate Tech Founders

For climate tech founders with validated technology and a clear path to commercial scale, All Aboard Fund I could open new doors.

This type of capital can help companies build first commercial facilities, expand production capacity, support project development, or enter new markets.

It’s especially relevant for sectors like long-duration energy storage, green hydrogen, carbon removal, advanced materials, industrial decarbonization, and other capital-intensive climate technologies.

These are the kinds of innovations that can reshape major industries, but only if they can move beyond pilots.

For the broader climate ecosystem, All Aboard Fund I signals something bigger: climate tech is maturing. The market now needs more than early-stage checks. It needs financing structures that can help companies cross the messy, expensive, and essential middle stage between invention and infrastructure.

That’s where some of the most important climate work will happen next.