The $45M-$100M "Missing Middle" - Why Climate Tech's Hardest Funding Gap Isn't Seed or Series A

General
1

Everyone talks about the Series A crunch. But the data shows a different story: the hardest funding gap for climate tech is actually between $45M and $100M.

The Missing Middle Problem

This range sits in a no-man’s-land:

  • Too large for traditional VC: Most growth funds max out around $30-50M checks
  • Too small for infrastructure investors: Infrastructure PE typically starts at $100M+
  • Too risky for project finance: Technology not yet proven at commercial scale

Where Companies Die

Looking at climate hardware company failures, here’s when they tend to fail:

Stage Failure Rate Primary Cause
Seed 25% Technology doesn’t work
Series A 30% Can’t find product-market fit
Series B 20% Unit economics don’t work
Missing Middle 40% Can’t fund first commercial facility
Scale-up 15% Execution failures at scale

The missing middle has the highest failure rate, yet gets the least attention.

Why This Gap Exists

VC Perspective

A $50M check from a $500M fund is 10% of the fund in a single bet. That’s concentrated risk. And if the company then needs another $100M for scale-up, the VC can’t follow on.

Infrastructure PE Perspective

“Call us when you have a permitted project with offtake agreements.” They want construction risk, not technology risk.

Project Finance Perspective

“We need 3+ years of operational data at commercial scale.” But you can’t get that data without capital to build.

The FOAK (First-of-a-Kind) Problem

69% of investors surveyed expect first-of-a-kind capital availability to shrink in 2026.

This is the funding that enables the transition from pilot to first commercial facility - exactly the missing middle.

What’s Working

Government catalytic capital: DOE’s Loan Programs Office and direct grants can fill the gap, but applications take 12-24 months.

Specialized climate funds: A few funds have raised specifically for this stage (Congruent Ventures, Prelude Ventures, etc.)

Strategic co-investment: Corporate strategics who want the technology sharing risk with financial investors.

Blended structures: Combining debt, equity, grants, and tax credits to make the capital stack work.

The missing middle is where climate tech goes to die. Until we solve it, many promising technologies will never reach commercial scale.

2

Rachel, that failure rate table is sobering. Let me add the technical perspective on what milestones actually fall in this missing middle.

Technical Milestones in the $45M-$100M Range

This is where the most critical technical de-risking happens:

Pilot to Demo Scale

  • Going from lab-scale (kg/day) to demo-scale (tons/day)
  • First time seeing real manufacturing defects at volume
  • Integration challenges that only appear at scale

Engineering Validation

  • Building the first full-scale unit
  • Testing cycle life under real operating conditions
  • Validating maintenance and serviceability

Process Optimization

  • Yield improvements from 60% to 85%+
  • Energy efficiency gains from process integration
  • Waste stream handling at scale

Why This Phase Is So Expensive

The costs are brutal because you’re:

  1. Building custom equipment - No off-the-shelf solutions at this scale
  2. Running 24/7 operations - Need continuous data over months
  3. Iterating on hardware - Each iteration might cost $5-10M
  4. Building the team - Need operators, maintenance, safety personnel

The Technical Catch-22

Infrastructure investors want proven technology. But you can’t prove the technology without the capital to build and operate at demo scale for 2-3 years.

The missing middle is fundamentally a technology risk problem disguised as a capital problem. Until investors are willing to take technology risk at this scale, the gap persists.

3

The creative financing structures that can bridge this gap are emerging, but they’re not simple.

Bridging Strategies That Work

1. The Convertible Project Finance Model

Structure:

  • Equity investors provide $20-30M for development
  • Project finance commits to $50-100M when milestones are hit
  • Early equity converts or gets bought out at defined terms

Why it works: Aligns incentives - equity investors de-risk for project finance, project finance provides the scale capital.

2. The ARPA-E to Commercial Pipeline

  • Start with ARPA-E grant ($2-5M) for early R&D
  • Use results to get DOE demonstration funding ($10-30M)
  • Apply for DOE Loan Guarantee ($50-200M) for first commercial

Why it works: Government takes technology risk, private capital comes in once technology is proven.

3. The Strategic Partner Bridge

Structure:

  • Corporate strategic provides $30-50M for demo facility
  • In exchange: right of first refusal on commercial scale, preferential pricing
  • Financial VCs come in once technology is validated

Why it works: Corporate gets technology optionality, startup gets patient capital and a customer.

4. Tax Credit Monetization

  • Structure project to generate IRA tax credits
  • Sell credits to tax equity investors for upfront cash
  • Use cash flow to service debt financing

Why it works: Converts future government incentives into today’s capital.

The CFO Complexity

Every one of these structures requires:

  • Multiple legal entities
  • Complex intercompany agreements
  • Different reporting for different investors
  • Treasury management across entities

It’s a full-time job just managing the capital structure. But it’s the only way to bridge the gap.

4

The missing middle shapes every engineering decision we make. Let me share how funding constraints affect technical choices.

Engineering Decisions Shaped by Funding Reality

Build vs. Buy Differently at Each Stage

When capital is plentiful (not now):

  • Custom equipment for optimal performance
  • Purpose-built facilities
  • Specialized tooling

When in the missing middle:

  • Retrofit existing industrial equipment
  • Lease facilities instead of build
  • Share infrastructure with partners

Phased Technical Approaches

We’ve had to redesign our technical roadmap around what can be funded:

Phase 1 - Shoestring Proof ($5-15M)

  • Use university lab facilities
  • Small-scale demonstration with modified commercial equipment
  • Prove the chemistry/physics works

Phase 2 - Scrappy Pilot ($15-30M)

  • Partner with existing industrial facility
  • Integrate into their operations for reduced capex
  • Generate real operational data

Phase 3 - Bootstrapped Demo ($30-60M)

  • Modular approach - build in stages
  • Revenue from partial operations to fund next module
  • Prove unit economics before full build-out

The Engineering Trade-offs

  1. Speed vs. cost: Can’t afford the fastest approach, optimize for capital efficiency

  2. Custom vs. standard: Standard equipment that’s 80% optimal beats custom that runs out of money at 90% complete

  3. Vertical integration vs. partnerships: Partner for everything non-core to reduce capital needs

The Human Cost

This funding environment means engineers are:

  • Doing more with less
  • Wearing multiple hats
  • Making technical compromises they wouldn’t make in a well-funded environment

The technical debt accumulates. Eventually it will need to be paid. But you have to survive to get there.