Heimdal: CO2 Removal & Sustainable Cement Production

Addressing Rising CO2 Levels with Ocean-Based Carbon Capture

The increasing levels of carbon dioxide in our atmosphere are directly correlated with rising CO2 concentrations in the ocean, posing significant threats to marine wildlife and disrupting established ecosystems. Heimdal, a pioneering startup, is actively developing a scalable solution to remove CO2 from the environment. Their approach leverages renewable energy sources to produce carbon-negative industrial materials, notably limestone for concrete production, and has already garnered substantial investment despite being in its initial phases.

Concrete Production and Seawater Minerals

The connection between carbon capture and concrete might not be immediately apparent. However, it’s estimated that concrete manufacturing accounts for as much as 8% of all global greenhouse gas emissions. Furthermore, seawater is naturally rich in the minerals essential for concrete production. This realization was key for Heimdal’s founders, Erik Millar and Marcus Lima, during their master’s programs at Oxford University.

Both founders share a strong conviction that climate change represents an existential threat to humanity. They were, however, dissatisfied with the prevalence of temporary solutions addressing the multifaceted consequences of this global challenge. Millar highlighted that carbon capture often involves a cyclical process – capturing emissions only to re-release them later. He questioned the lack of methods for permanently removing carbon from the environment.

A Linear Process for Permanent Carbon Sequestration

The founders envisioned a novel, linear process that utilizes only electricity and CO2-rich seawater to generate valuable materials while permanently sequestering carbon dioxide. They acknowledged the inherent challenges in realizing such a process, stating that widespread implementation would already be occurring if it were simple.

Image Credits: Heimdal

“The necessary carbon markets to ensure economic viability have only recently materialized,” Millar explained. Simultaneously, the cost of energy has dramatically decreased due to the expansion of solar and wind power. The combination of carbon credits and affordable energy creates new business opportunities, and Heimdal’s model is a prime example.

The Heimdal Process: From Seawater to Valuable Materials

The Heimdal process, currently demonstrated at a laboratory scale, involves several key steps. Initially, seawater is alkalinized, increasing its pH and facilitating the isolation of gases like hydrogen and chlorine, alongside a hydroxide sorbent. This mixture is then combined with another stream of seawater, leading to the precipitation of calcium, magnesium, and sodium minerals. This process also reduces the saturation of CO2 in the water, enhancing its capacity to absorb CO2 from the atmosphere upon its return to the ocean.

Image Credits: Heimdal

Ultimately, the process transforms seawater and electricity into hydrogen and chlorine gas, calcium carbonate, sodium carbonate, and magnesium carbonate, effectively sequestering significant amounts of dissolved CO2. For every kiloton of seawater processed, one ton of CO2 is isolated, alongside two tons of valuable carbonate minerals.

Industrial Applications of the Carbonates

MgCO3 and Na2CO3 find applications in industries like glass manufacturing. However, CaCO3, commonly known as limestone, holds the greatest potential impact. Limestone is a crucial component in cement production, a sector currently responsible for substantial atmospheric carbon emissions. Industries worldwide are investing in carbon reduction strategies, with a growing preference for genuinely carbon-negative processes over mere financial offsets.

Synergies with Desalination Plants

To further enhance its viability, Heimdal is exploring collaborations with desalination plants. These facilities, prevalent in regions with limited freshwater resources but abundant seawater and energy – such as California, Texas, and the MENA region – produce highly saline brine as a byproduct. Traditionally, this brine requires treatment to avoid disrupting local ecosystems.

Heimdal proposes integrating its mineral-collecting process between the desalination plant and the ocean. This would allow the plant to effectively manage its brine byproduct while providing Heimdal with a concentrated source of minerals. “Heimdal’s ability to use brine effluent to produce carbon-neutral cement solves two problems at once,” stated Yishan Wong, former Reddit CEO and current CEO of Terraformation, and an investor in Heimdal.

A Scalable Solution for Carbon-Neutral Cement

Wong emphasized that Heimdal’s approach creates a scalable source of carbon-neutral cement and transforms desalination brine into a valuable economic product. The potential for scaling this integrated system is transformative. Terraformation, a strong advocate for solar desalination, recognizes the synergy with Heimdal and is developing a formal partnership.

The primary cost driver for Heimdal’s business, beyond initial infrastructure investments, is the cost of solar energy. With ongoing investments and declining costs, this expense is expected to continue decreasing. The potential profit per ton of CO2 captured – currently around 75% of $500-$600 in revenue – is also projected to increase with scale and efficiency.

Competitive Pricing and Seamless Integration

Millar noted that their limestone is already price-competitive with industry standards when factoring in government incentives and subsidies. As energy costs fall and production scales up, this advantage will become even more pronounced. Importantly, their product is chemically indistinguishable from naturally sourced limestone. “We don’t require any retrofitting for the concrete providers – they just buy our synthetic calcium carbonate rather than buy it from mining companies,” he clarified.

Investment and Future Outlook

Heimdal’s promising potential has attracted a $6.4 million seed round from investors including Liquid2 Ventures, Apollo Projects, Soma Capital, Marc Benioff, Broom Ventures, Metaplanet, Cathexis Ventures, and Yishan Wong. The company has already secured Letters of Intent (LOIs) with major cement and glass manufacturers and is planning its first pilot facility at a U.S. desalination plant.

Following the delivery of test products to partners, totaling tens of tons, Heimdal anticipates commencing commercial production in 2023.