CO2 storage following the application of Limenet technology in Augusta site

Carbonmark : CMARK-2-2024

Accredia

RINA

Limenet

The purpose of the project activity is to install a Limenet storage plant at the gulf of Augusta (Siracusa, Italy) in order to permanently store CO2 in the form of calcium bicarbonates in seawater to remove CO2 emissions from the atmosphere and generate negative emissions. The aim of this document is to describe specifically the plant built in Augusta and calculate the removal of CO2 emissions due to the storage of CO2 in the form of calcium bicarbonates, by applying Limenet technology. The aim of Limenet is to remove CO2 emissions which come from different sources. CO2 can come from Direct Air Capture (DAC), biomass or other external sources. Depending on the process from which CO2 has been obtained, the type of CO2 storage will be considered removal or avoidance. The Augusta project aims at storing only biogenic CO2 after initial tests with technical CO2.

Verification Report of Voluntary Declarations Related to Greenhouse Gas Projects

Project Design Document CO2 storage following the application of  Limenet technology  in Augusta site

Methodology CO2 storage following the application of Limenet technology

Limenet is an Italian climate tech company revolutionizing carbon removal with its patented pH-equilibrated Ocean Alkalinization technology—a groundbreaking method that accelerates the natural oceanic carbon cycle to combat anthropogenic emissions. This innovative approach permanently stores CO₂ in seawater as equilibrated calcium bicarbonates, increasing ocean alkalinity and helping restore marine ecosystems affected by acidification.

Technology & Methodology

Limenet’s process mirrors and amplifies the Earth’s natural geochemical cycles. The company captures CO₂ from the atmosphere or industrial sources, such as the Iren biogas plant in Reggio Emilia, and reacts it with calcium carbonate (lime) and seawater in a controlled reactor. This reaction produces an aqueous solution of calcium bicarbonates, which is then released into the ocean. The result is a stable, long-term carbon sink, capable of sequestering CO₂ for over 10,000 years, while simultaneously improving ocean chemistry.

Limenet’s industrial-scale pilot plant, operational since September 8, 2023, in Augusta, Sicily, is the world’s largest facility for ocean-based CO₂ storage. It currently processes 100 kg of CO₂ per hour, with an annual target of 800 metric tons, and aims to scale up to 100,000 metric tons per year by 2028.

Environmental Impact & Co-Benefits

BOAE technology not only removes carbon dioxide from the atmosphere but also provides a range of additional environmental benefits. By increasing ocean alkalinity, this approach plays a crucial role in mitigating ocean acidification, a major threat to marine ecosystems. The process fosters a more hospitable environment for marine biodiversity, particularly benefiting coral reefs, seagrasses, and calcifying organisms that depend on stable pH levels for survival.

In addition to enhancing biodiversity, Limenet’s technology supports fisheries and coastal ecosystems by stabilizing ocean chemistry, thereby promoting healthier fish populations and protecting marine food webs. Species highly sensitive to pH fluctuations, such as plankton and mollusks, benefit from these improvements, ensuring the resilience of oceanic ecosystems.
This initiative is particularly significant in Augusta, Sicily, where the site’s history as the quadrilatero della morte(Quadrilateral of Death)—an area devastated by petrochemical pollution—is being transformed into a beacon of environmental restoration.

Scientific Rigor & Digital Transparency 

Limenet’s technology is backed by years of scientific research from leading institutions such as Politecnico di Milano and Università Milano-Bicocca. Their research group, Desarc Maresanus, has published over 10 scientific papers validating this approach. The company’s proprietary carbon removal methodology has been independently verified by RINA, one of the world’s oldest and most respected verification bodies.

To ensure full transparency, Limenet has developed a state-of-the-art digital monitoring, reporting, and verification (dMRV) system, leveraging blockchain technology. Real-time data on CO₂ sequestration is recorded and securely stored on the Polygon blockchain, eliminating the risk of double counting and ensuring public accountability.

Limenet’s carbon removal credits adhere to ISO 14064-2 standards and are natively issued on a public blockchain-based system via the Carbonmark Direct solution.

Scaling Ocean-Based Carbon Removal

As one of the few companies globally leveraging the ocean for CO₂ sequestration, Limenet is positioning itself as an industry leader. With a patented process, a commitment to scientific excellence, and digital transparency, Limenet is set to make a lasting impact in the fight against climate change.

CO2 storage following the application of Limenet technology

CO2 storage following the application of  Limenet technology in Augusta site

Limenet is an Italian climate tech startup pioneering carbon removal through its patented pH-equilibrated Ocean Alkalinization technology. By mimicking natural processes, Limenet permanently stores CO₂ in seawater as calcium bicarbonates. In addition to carbon removal, this solution combats ocean acidification and helps restore marine ecosystems—delivering scalable, transparent, and scientifically verified results.