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Lithos raises $6.3m to bring ERW carbon capture to scale

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Lithos Carbon has raised $6.3 million in seed funding round to scale and commercialise its enhanced rock weathering (ERW) carbon capture technology. 

  • Enhanced rock weathering involves spreading crushed minerals over agricultural land to accelerate a natural process of permanent carbon capture and sequestration. 
  • Up to two billion tons of CO2 must be captured by 2030 in order to meet net zero by 2050, but existing technologies are failing to deliver. 
  • The development of economic incentives for carbon capture will be crucial in bringing innovative technologies to scale. 

Lithos Carbon has closed a $6.3 million seed round, led by Union Square Ventures and Greylock, which will be used to bring its enhanced rock weathering (ERW) carbon capture to scale. The Washington-based start-up aims to sequester 10,000 tons of CO2 in 2023. It projects that if it is able to scale up by five to 10 times each year, a billion tons of CO2 could be removed by 2030. 

“This funding supports our vision to shape the future of low-cost, highly-scalable, and directly-measured carbon removal in agriculture.  Leveraging a decade of rigorous research, we are moving at a speed that the climate crisis demands”, the company said. 

What is enhanced rock weathering? 

Rock weathering is a natural component of the Earth’s carbon cycle, identified by scientists over 50 years ago. The process occurs as rainwater, made slightly acidic by the CO2 in the atmosphere, reacts with exposed silicate rocks exposed on the Earth’s surface. 

A chemical reaction between the acidic rainwater and the rock surface then turns the atmospheric CO2 into bicarbonate, which gradually runs into the ocean where it is permanently sequestered as solid limestone. This natural process can be enhanced, or sped up, by crushing silicate rocks to reduce their surface size and spreading the ground up minerals over large bodies of land. 

Lithos’ ERW process applies crushed basalt, the most abundant volcanic rock available, to agricultural soils. The firm says that for each three tons of basalt applied, up to 1 ton of CO2 can be captured. 

The need for innovation in carbon capture 

In order to stay on track to meet a net zero by 2050 scenario, between one and two billion tons of CO2 must be captured in 2030. According to research by Bloomberg NEF, however, only 0.1% of global carbon emissions are currently being captured. Even if the current pipeline of projects is realised, carbon capture capacity in 2030 would account for just 0.6% of today’s emissions. 

Existing carbon capture technologies have been limited in their commercial viability, due to high costs, technological constraints and the need to invest in large-scale transportation and storage infrastructure. Indeed, a report from the Institute for Energy Economics and Financial Analysis suggests that the majority of existing carbon capture projects are underperforming.  

The Energy Transitions Authority, meanwhile, has warned that bringing CO2 removal to the necessary scale would require up to $15 trillion in investment over the next thirty years. 

In addition to the investment and technological development needed to scale carbon capture, existing technologies are also associated with several controversial trade-offs. Bioenergy with carbon capture and storage (BECCS), for example, has been criticised for its excessive land use, lifecycle emissions and its impacts on food security and biodiversity. 

ERW has several co-benefits 

ERW could provide a solution to some of these issues. Research suggests that it uses less land than BECCS, afforestation, reforestation or biochar projects and around half as much energy as mechanical direct air capture solutions. It also consumes between 10 and 100 times less water than these alternative strategies. Furthermore, ERW is considered one of the cheapest carbon capture technologies available. 

A study published by the University of Sheffield in 2022 reveals several co-benefits that could be gained from ERW. It says that ERW can help to reduce the soil acidification caused by intensive agriculture, while also serving as a replacement for traditional fertilisers. In doing so, ERW would lower the demand for costly fertiliser imports while also reducing the nitrous oxide emissions associated with chemical inputs. 

According to the study, applying ERW to the UK’s agricultural soils could remove up to 30 million tonnes of CO2 annually by 2050. This figure equates to around 45% of the country’s emissions reduction targets. 

Senior author Professor David Beerling said: “Our analysis highlights the potential of UK agriculture to deliver substantial carbon drawdown by transitioning to managing arable farms with rock dust, with added benefits for soil health and food security.” 

Naturally, there are some drawbacks to ERW that must also be considered. The mining, grinding and transportation of rocks, for example, results in CO2 emissions, air pollution and operational costs.  

These impacts could be partially limited by the use of renewable energy in mining operations, the electrification of transport networks, or reducing the distance between the rocks’ source and its end deployment. There is also a need for further research on the impact of ERW on aquatic biodiversity, with some suggesting that it could contribute to eutrophication. 

Leveraging economic incentives to bring ERW to scale 

The process simplicity, low cost, global abundance of basalt rock and availability of deployment infrastructure make ERW a promising solution for carbon capture that can be rapidly upscaled.  

Lithos plans to accelerate this adoption by leveraging several economic incentives, such as by sourcing its ground basalt from industrial waste. In doing so, it could allow demolition waste or steel slag to be upcycled in support of a circular economy and provide sustainable revenue and employment opportunities in sectors such as coal mining. 

Futhermore, the start-up has created a software that enables it to work with farmers to develop site-specific approaches that optimise its process to deliver the best improvements in crop yields, crop resilience, soil health and carbon sequestration. 

It has also developed a system for measuring captured CO2 from farm-to-ocean, allowing it to issue accurately verified carbon credits after the carbon has been removed rather than based on future predictions.  

The company pays for farmers’ ERW feedstock delivery, soil sampling and application, then sells carbon credits to purchasers seeking a credible, transparent and trustworthy approach to carbon offsetting. As such, it incentivises farmers to participate in the voluntary carbon market by reducing the costs, resource requirements and technical understanding required. 

By capitalising on the economic advantages of ERW, Lithos could be well-positioned to bring the technology to scale. With over $3 billion invested in carbon capture in 2022 so far, there is certainly a market for its approach.

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