Heimdal extracts CO2 and cement-making materials from seawater using renewable energy – TechCrunch

One of the consequences of increasing CO2 levels in our atmosphere is that levels also increase proportionately in the ocean, harming wildlife and changing ecosystems. Heimdal is a startup that works to extract this CO2 on a large scale using renewable energy and producing carbon-negative industrial materials, including limestone to make concrete, and it has attracted significant funding even in its early days.

If the concrete aspect seems to be a bit of a non sequitur, consider two facts: It is estimated that the manufacture of concrete produces up to 8% of all greenhouse gas emissions, and seawater is full of minerals used to make it. You probably wouldn’t make this connection unless you were working in a related industry or discipline, but Heimdal founders Erik Millar and Marcus Lima did so while working in their respective masters programs at Oxford. . “We went out and did this right away,” he said.

They both firmly believe that climate change is an existential threat to humanity, but have been disappointed by the lack of permanent solutions to its many and diverse consequences across the world. Carbon capture, Millar noted, is often a circular process, meaning it is captured only to be used and emitted again. Better than producing new carbons, of course, but why aren’t there more ways to get them out of the ecosystem for good?

The two founders envisioned a new linear process that consumes only electricity and seawater with a high CO2 content and produces useful materials that permanently sequester gas. Of course, if it was that easy, everyone would be doing it already.

Image credits: Heimdal

“The carbon markets to make this economically viable have only just been formed,” Millar said. And the cost of energy has plummeted through the ground as massive solar and wind power plants rocked decades-old energy savings. Along with carbon credits (the market I won’t explore, but suffice to say it’s a catalyst) and cheap electricity come new business models, and Heimdal’s is one of them.

The Heimdal process, which has been demonstrated on a lab scale (think terrariums instead of thousand gallon tanks), is roughly as follows. First, seawater is alkalized, increasing its pH and allowing the isolation of hydrogen gas, chlorine and a hydroxide sorbent. This is mixed with a separate stream of seawater, causing the minerals calcium, magnesium and sodium to precipitate and reducing the saturation of CO2 in the water, allowing it to absorb more of the atmosphere when returned to the sea. (I was shown an image of the small-scale prototype installation but, citing pending patents, Heimdal declined to provide the photo for publication.)

A diagram describing the Heimdal carbon extraction process

Image credits: Heimdal

Thus, from seawater and electricity, they produce hydrogen and chlorine gas, calcium carbonate, sodium carbonate and magnesium carbonate, and in the process sequester a large part of the CO2 dissolved.

For each kilotonne of seawater, one tonne of CO2 and two tonnes of carbonates are isolated, each for industrial use. MgCO3 and Na2CO3 are used, among other things, in the manufacture of glass, but it is CaCO3, or limestone, that has the greatest potential impact.

As a major component of the cement manufacturing process, limestone is always in high demand. But current methods of supply are huge sources of atmospheric carbon. Industries around the world are investing in carbon reduction strategies, and although purely financial offsets are common, in the future the preferred alternative is likely to be carbon-negative processes.

To further stack the bridge in his favor, Heimdal seeks to work with desalination plants, which are common in the world where fresh water is scarce but sea water and energy are plentiful, for example the coasts of California and Texas in the United States, and many other parts of the world, but especially where deserts meet the sea, such as in the MENA region.

Desalination produces fresh water and a proportionately saltier brine, which usually needs to be treated, as simply returning it to the ocean can upset the local ecosystem. But what if there was, say, a process of collecting minerals between the plant and the sea? Heimdal benefits from more minerals per tonne of water, and the desalination plant has an efficient way to manage its salty by-products.

“Heimdal’s ability to use brine effluent to produce carbon neutral cement solves two problems at once,” said Yishan Wong, former CEO of Reddit, now CEO of Terraforming and individually an investor in Heimdal. “It creates a scalable source of carbon neutral cement and converts the brine effluent from desalination into a useful economic product. Being able to change this together is a game-changer on several levels. “

Terraforming is a big supporter of solar desalination, and Heimdal fits perfectly into this equation; the two are working on a formal partnership which is expected to be announced shortly. Meanwhile, a negative carbon source for limestone is something cement makers will buy every gram in their efforts to decarbonize.

Wong points out that the main cost of Heimdal’s business, beyond the initial costs of purchasing tanks, pumps, etc., is solar power. The trend has been declining for years and with huge sums invested regularly, there is no reason to believe the cost will not continue to fall. And the profit per tonne of CO2 captured – already around 75% of the $ 500-600 in revenue – could also increase with scale and efficiency.

Millar said the price of their limestone, when government incentives and subsidies are included, is already at price par with industry standards. But as energy costs go down and scales increase, the ratio will become more attractive. It is also pleasant that their product is indistinguishable from “natural” limestone. “We don’t require any upgrades for the concrete suppliers – they just buy our synthetic calcium carbonate rather than buying it from mining companies,” he explained.

Overall, this appears to be a promising investment, and while Heimdal has yet to make his public debut (reportedly coming up on Y Combinator’s summer 2021 demo day), he has attracted a funding round of $ 6.4 million. Participating investors are Liquid2 Ventures, Apollo Projects, Soma Capital, Marc Benioff, Broom Ventures, Metaplanet, Cathexis Ventures and, as mentioned above, Yishan Wong.

Heimdal has already signed letters of intent with several major cement and glass manufacturers and is considering its first pilot plant at a desalination plant in the United States. After providing its partners with test products on a scale of several tens of tonnes, they plan to enter commercial production in 2023.

Comments are closed.