ClearFlame Engines is a technology company.
ClearFlame Engines has raised $50.0M across 3 funding rounds.
ClearFlame Engines has raised $50.0M in total across 3 funding rounds.
ClearFlame Engines has raised $50.0M in total across 3 funding rounds.
ClearFlame Engines's investors include Ag Startup Engine, Breakthrough Energy Ventures, Clean Energy Ventures, Powerhouse Ventures, Prelude Ventures, Vitalize Venture Group, Wind Ventures, 2048 Ventures, Bain Capital Ventures, Liquid 2 Ventures, Matchstick Ventures, Monochrome Capital.
# ClearFlame Engine Technologies: High-Level Overview
ClearFlame Engine Technologies is a clean-tech startup that modifies heavy-duty diesel engines to run on renewable, plant-based fuels instead of diesel fuel.[1][4] Founded in 2016 by Dr. BJ Johnson (CEO) and Dr. Julie Blumreiter (CTO), both mechanical engineers with doctoral research from Stanford University, the company addresses a critical decarbonization challenge: how to rapidly reduce emissions from sectors that are difficult to electrify.[3][4]
The company's core offering is patented engine modification technology that allows existing and new diesel engines to operate on clean, renewable liquid fuels—primarily ethanol—while maintaining the same performance, durability, and cost-effectiveness as traditional diesel engines.[3][4] This approach achieves approximately 45% reduction in CO₂ emissions and 99% reduction in soot and particulate matter compared to conventional diesel engines.[1] ClearFlame serves heavy-duty sectors including long-haul trucking, agriculture, power generation, and construction—markets representing 3.3 million Class 8 trucks on U.S. roads alone.[1] The company solves the fundamental problem that electric powertrains face significant barriers for heavy-duty applications, offering an immediate, scalable decarbonization pathway without requiring new infrastructure or green premiums.[3]
# Origin Story
ClearFlame emerged from rigorous academic research. Co-founders Johnson and Blumreiter developed the foundational combustion technology during their doctoral studies at Stanford University and subsequent work at Argonne National Laboratory.[4] The company was established as a Black- and Women-founded business with an explicit commitment to addressing climate change alongside energy equity and environmental justice issues.[4]
The startup gained early validation through substantial grant funding—over $3 million in research support—from agencies including the Department of Energy, Department of Agriculture, and the National Science Foundation.[4] In October 2021, ClearFlame secured $17 million in Series A financing led by Breakthrough Energy Ventures, with participation from Mercuria, John Deere, and Clean Energy Ventures.[5] This funding enabled commercialization efforts, with demonstration trucks deployed by the end of 2021 and agricultural equipment and generator deployments planned for 2022.[5] Mercuria subsequently led a second investment round, reinforcing confidence in the technology's market potential.[3]
# Core Differentiators
# Role in the Broader Tech Landscape
ClearFlame operates at the intersection of three powerful trends: the urgent need for rapid decarbonization, the limitations of electrification for heavy-duty applications, and the growing availability of renewable fuels. Diesel fuel consumption accounts for approximately 26% of overall CO₂ emissions from the U.S. transportation sector, making heavy-duty decarbonization a critical climate lever.[3]
The company's timing is strategically advantageous. While electric vehicles dominate climate narratives, the physics and economics of battery-powered long-haul trucks and agricultural equipment remain prohibitively challenging. ClearFlame fills this gap by offering a pragmatic, near-term solution that leverages existing industrial infrastructure rather than waiting for transformative breakthroughs. The company's focus on "hard-to-electrify" sectors positions it as a complement to, rather than competitor with, electrification efforts—expanding the total addressable decarbonization opportunity.
ClearFlame's influence extends beyond its direct market impact. By demonstrating that internal combustion engines can be rapidly decarbonized through fuel switching rather than complete redesign, the company influences how policymakers, fleet operators, and equipment manufacturers think about emissions reduction timelines and pathways. The involvement of major industrial players like John Deere signals that traditional equipment manufacturers view this technology as strategically important to their own decarbonization roadmaps.
# Quick Take & Future Outlook
ClearFlame stands at an inflection point. The company was awaiting EPA regulatory approval as of late 2023 to enable full commercialization.[6] Once cleared, the path to scale is relatively straightforward: retrofitting the existing installed base of 3.3 million Class 8 trucks represents an enormous addressable market, followed by agricultural and power generation sectors.
The company's future will likely be shaped by three factors: regulatory approval timelines, the competitive emergence of alternative heavy-duty decarbonization technologies, and the trajectory of renewable fuel availability and pricing. If ClearFlame successfully navigates EPA approval and demonstrates real-world performance at scale, it could become a critical infrastructure for industrial decarbonization—not as a replacement for electrification, but as the pragmatic near-term solution for sectors where batteries remain impractical. The founders' academic rigor, combined with strategic investor backing from both climate-focused and traditional industrial capital, suggests the company is well-positioned to capture this opportunity and influence how the heavy-duty sector approaches its climate transition.
ClearFlame Engines has raised $50.0M across 3 funding rounds. Most recently, it raised $30.0M Series B in March 2023.
| Date | Round | Lead Investors | Other Investors |
|---|---|---|---|
| Mar 1, 2023 | $30.0M Series B | Ag Startup Engine, Breakthrough Energy Ventures, Clean Energy Ventures, Powerhouse Ventures, Prelude Ventures, Vitalize Venture Group, Wind Ventures | |
| Oct 1, 2021 | $17.0M Series A | Breakthrough Energy Ventures, Powerhouse Ventures, Prelude Ventures | |
| Apr 1, 2020 | $3.0M Seed | 2048 Ventures, Ag Startup Engine, Bain Capital Ventures, Clean Energy Ventures, Liquid 2 Ventures, Matchstick Ventures, Monochrome Capital, OCA Ventures, Union Square Ventures, Village Global, Vitalize Venture Group, Mark Ghermezian |