A fundamental breakthrough in carbon mineralization

Scaling Heirloom’s direct air capture technology

Over the past ten months, our scientists and engineers have been quietly chipping away at one of the most important engineering challenges facing humanity: the removal of carbon dioxide from thin air. We are excited to finally share a white paper about our journey towards achieving gigaton-scale, low-cost direct air capture — including a major breakthrough in our carbon mineralization process.

Read the white paper here.

The Heirloom approach

In their 2018 Special Report, the IPCC revealed that, with high confidence, every pathway that will limit warming to 1.5°C requires carbon dioxide removal to mitigate emissions from hard to abate sectors and remove CO2 already in the atmosphere. Reducing emissions across all sectors is critical, but we won’t hit our climate targets without employing permanent and high quality forms of carbon dioxide removal, such as direct air capture.

In April of 2021, when we first announced Heirloom, we were a sheltered-in-place, remote team of 4 with an idea. Armed with some experimental results and plenty of ambition, we set out to build a direct air capture system so affordable and scalable that it could single-handedly remove billions of tons of CO2 from the atmosphere. We had a vision of a system that relied on cheap, earth-abundant minerals, a simple, modular design, and off-the shelf technologies borrowed from well-established industries. We wanted to build a solution that would not compromise the health of people or the environment — something to look back on 30 years from now with pride.

Since then, 35 engineers, scientists, and concerned citizens have joined us to tackle this problem. We have transformed a neglected warehouse into a vibrant headquarters, scaled up our process thousands of times, and iterated through the first three versions of our passive air contactor. Though we still have so far to go, the possibilities of cheap, scalable direct air capture become more real every day.

Today we want to give a peek behind the curtain and share more about the breakthrough that unlocked a $53M Series A from some of the best climate investors on the planet.

A fundamental breakthrough in carbon mineralization

The Heirloom process works by exposing rocks to the atmosphere and letting them naturally react with CO2 in a process known as “carbon mineralization”. The rocks are then heated to release the CO2, which is then captured and safely pumped underground into rock formations where it is stored permanently. While there is plenty of clever science and engineering that makes it all work, the beauty of Heirloom’s process lies in its simplicity.

While carbon mineralization occurs over long timescales in nature, we can speed up the process substantially, resulting in fewer minerals, less capital expenditure, and less time needed to capture the same amount of CO2.

We launched Heirloom with the understanding that the timescale of the carbonation process could be reduced from years in nature down to just four weeks. That was fast enough to give us confidence in the approach, but not fast enough to reach sub-$100/ton costs. But in the past 10 months, through thousands of hours of experimentation and development, our scientists and engineers have made as close to a fundamental breakthrough in carbon removal as you can get by accelerating the process further. We’ve taken that process, which took roughly 4 weeks when we launched, and improved it by a factor of 10. We are now consistently observing 85% carbonation extents in just 2.5 days, a metric which, when combined with our modular, simple system design, has unlocked a clear glide path to ultra-low-cost direct air capture.

We’re sharing more about the process for the first time, including a closer look at the results of those experiments. This white paper covers the process, system design, and scaling strategy behind Heirloom’s technology. We can’t wait to hear what you think.

Our principles, and building the right team for the job

We are incredibly proud of the people that have come together to build Heirloom. Our team hails from cutting edge tech companies and top research institutions, drawing expertise from a diversity of technical backgrounds and disciplines, from industrial automation to geochemistry. Together we’re using our collective experience to build a more equitable, prosperous future for all.

We are a united, resilient, and optimistic bunch, and are all here for the same reason: to slow climate change. We recognize the magnitude of the challenge ahead of us, and believe we can solve it. We can see a hopeful future where we reverse climate change.

But building this industry as quickly as we need will require many, many more motivated minds.

We need people from all walks of life, with a shared motivation, aligned behind common principles to succeed. Heirloom is committed to diversity and building an equitable and inclusive environment for people of all backgrounds and experiences. We believe wholeheartedly that building a diverse company is critical to Heirloom’s success.

This is a multi-decade journey, and the people on that journey will define the path we take. If these principles resonate with you, please apply. We especially encourage members of traditionally underrepresented communities to apply, including women, people of color, LGBTQ+ people, veterans, and people with disabilities. There’s no better time than right now.

Our principles:

• Radical Honesty. We are open, transparent, and inclusive in everything we do. We aren’t scared to challenge each other, but bring clear motives and our best intentions when we do.
• Persistent Optimism. We carry an infinite amount of optimistic energy with us on our journey, constantly chipping away at what may seem insurmountable.
• Maximizing Our Learning Rate. Compounding knowledge is our key to victory — we continuously hone our crafts, seek the fastest paths to new learning, and are quick to absorb new knowledge.

What’s next

Today represents a small milestone on our collective journey to slow climate change. While it’s always worth celebrating progress, there’s a long, long way to go. Over the next year we will deploy our technology at commercial scale for the first time, and show the world that this can make a meaningful difference.