Enhanced Rock Weather and Eion's New Initiatives

Frontier buyers sign $33M in offtake agreements with Eion - Frontier Climate

Enhanced Rock Weathering (ERW) is a carbon removal strategy that also functions as a soil amendment/fertilizer for crop production as well.

I haven’t covered ERW much in Upstream, so wanted to give a baseline overview.

By spreading finely crushed silicate rocks (often volcanic in origin, like basalt or olivine) onto field, ERW accelerates geochemical weathering processes to draw CO₂ out of the atmosphere and store it in stable forms over long time horizons.

The process sequesters carbon and can also enhance soil fertility, making ERW a dual-purpose carbon management and agronomic tool.

Scientific Basis of ERW: Geochemistry and CO₂ Uptake

ERW “supercharges” the natural chemical weathering of silicate minerals. Silicate rocks (such as basalt, peridotite/olivine) contain minerals rich in calcium (Ca), magnesium (Mg), potassium (K), silicon (Si), and other elements. When exposed to carbon dioxide and water, these minerals undergo chemical reactions that consume CO₂ and produce carbonate compounds.

Rainwater absorbs atmospheric CO₂, forming carbonic acid. This reacts with crushed silicate rock in soil, releasing cations (like Ca²⁺ and Mg²⁺) and converting CO₂ into dissolved bicarbonate (HCO₃⁻). These bicarbonates are eventually washed into waterways and oceans, where they can effectively lock up carbon for a long, long time.

Eion

Eion is a U.S.-based ERW company, that just sold a $33 million offtake agreement via Frontier to deliver more than 78,000 tons of CO₂ removal between 2027 and 2030.

The company focuses on crushed olivine mined by investor-partner Sibelco. The mineral dissolves in soil over 1–4 years, manages soil acidity, and sequesters atmospheric CO₂ via bicarbonate formation.

Olivine is applied at a 1:1 rate with ag lime (typically ~1 ton/acre), with no operational change for the farmer or ag retail applying.

One thing that differentiates Eion apart is its MRV (measurement, reporting, verification) tech. The company holds a patent on its “soil fingerprinting” method, using trace elements like magnesium and nickel as proxies to determine how much olivine has weathered—and by extension, how much CO₂ has been removed.

Price

The one challenge is the incremental price for olivine. The product costs 50+% more than lime per acre for the farmer. However, part of the logic of using the olivine vs. lime is that a farmer can access a high value carbon credit to offset a significant portion of that increase cost. What’s interesting is that ERW carbon credits are worth more (because of permanence) and can get upwards of $300-$500/ton. Even with that, there is still a challenge on a unit economics basis for Eion to incentivize the farmer enough, while still capturing margin themselves, and reaching the scale possible to bring the per ton cost of olivine down to make it even more price competitive with lime. Just like any physical goods business in agriculture, scale can bring down the cost and in a conversation with CEO Anastasia Pavlovic and founder Adam Wolf, the closer this gets to volumes of close to 7 figure tonnage per year, the closer to parity, or better, this product becomes.

GTM

Eion gets product to the farmer via partners like Southern Ag and GROWMARK and supporting the logistical reach to access into new geographies.

In Illustrative AgTech Insights: The Last Mile Driving Product Decisions in Agribusiness I wanted to reinforce the importance of getting groups like retailers on board— Eion is leaning into this with GROWMARK, and doing so with the right incentives: GROWMARK can make money on the ton of product sold, plus a cut from the carbon credit side the farmer gets. Eion plans to bring on more retailers in the near future.