Case Study: Carbon Cell

Following the news Carbon Cell have recently closed a £1.2M funding round to scale their low carbon, plastic-free foam technology, we spoke to CEO, Elizabeth Lee. With Carbon Cell being an Onnu customer, we were keen to delve a bit deeper into their start-up journey, as well as their mission to replace plastic foam, using biochar as a primary ingredient.

There are many different ways our biochar gets used - whether that is in soil remediation, for commercial growers, or for use in animal bedding. We love how versatile biochar is and, every now and then, our biochar gets put to use in a way that we never would have imagined - Carbon Cell certainly fit into that category!

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“We've been working with biochar since mid-2022, when we were studying at Imperial College London. Our decision to start working with biochar was as much about the opportunity as it was a problem.”

 - Elizabeth Lee, Carbon Cell

Carbon Cell is a London-based startup developing a sustainable, high-performing alternative to traditional plastic foams like expanded polystyrene (EPS). Their product is fully compostable and carbon-negative, made from biochar and natural polymers.

Carbon Cell’s core innovation is a patent-pending expandable foam that offers:

• Carbon Negativity: Carbon Cell’s foam is made with biochar. Biochar is stable, carbon-rich and produced from biomass waste via pyrolysis – a process that locks carbon away for centuries, preventing CO₂ from entering the atmosphere.

• High Performance: Carbon Cell’s foam is three times stronger than expanded polystyrene (EPS), has competitive thermal insulation, performs well under fire, and offers sound insulation comparable to conventional foams.

• Full Compostability: It can decompose in home composting conditions, making it a truly circular material.

• Flexible Manufacturing: The foam can be moulded into various shapes, making it suitable for applications in packaging, construction, and insulation.

“We quickly realised biochar’s potential for massive carbon dioxide removal. We need more, and more valuable uses for the resulting char than simply use in agriculture, in order to support growth. That's where our problem-solution fit comes in. By leveraging biochar's natural properties (highly porous, moisture buffering, thermally resistive) we are able to create a foam material that aids the built environment and manufacturing sector in transitioning away from petrochemical-based plastics, and towards bio-based alternatives.”

-Elizabeth Lee, Carbon Cell

According to Carbon Cell, in 2024 alone, over 10 million tonnes of expanded polystyrene were produced, enough material to cover the continent of Europe 50mm thick. Carbon Cell’s material replaces plastic foams such as expanded polystyrene, expanded polypropylene, and PUR/PIR, a collective market worth over $109BN.

The start-up’s latest round of funding will support their scale up from batch processing to continuous production. Carbon Cell are also working with early customers to deliver several thousand units of product for testing, evaluation, and trial.

“Biochar is a critical piece of our low-carbon foam technology, and we will continue to use it to improve performance and lower the carbon footprint of our core products.”

-Elizabeth Lee, Carbon Cell

We’ll be keenly following Carbon Cell’s progress over the coming years and hope that their innovative use of biochar inspires others to use the material in ways that push boundaries and contribute to a climate-positive solution.

You can find out more about Carbon Cell here.

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