Could ancient shipwrecks at the bottom of the Black Sea hold the key to effective carbon sequestration? That was the premise that prompted the creation of Rewind, a company that has pledged to ‘rewind the clock on climate change‘.
Founded in Tel Aviv in 2022, Rewind’s approach to carbon sequestration is inspired by how plants absorb carbon – rather than using conventional carbon capture technologies that extract and store carbon underground, the firm uses biomass, such as agricultural waste and plant matter, as a ‘natural’ form of carbon storage.
“Understanding that reducing emissions is already not enough to mitigate climate change, Rewind’s story began with the question: how can we sequester gigatons of carbon today, with humanity’s existing resources?” Rewind’s chief executive, Ram Amar, tells SustainabilityOnline. “This question quickly leads one to look at plants, which already capture 50 gigatons of CO2 per year, equivalent to humanity’s annual emissions.
“The problem with plants is that they ‘breathe’ the CO2 on an annual cycle – whatever amount of CO2 that is captured, is also released back to the atmosphere. So Rewind’s quest turned to plant storage: where on earth can we preserve gigatons of plants for thousands of years?”
Here’s where the Black Sea comes in. Given its anoxic conditions, which limit the breakdown of organic material – with “wood, ropes, and even wine that has been preserved for 2,000 years,” says Amar – it represents the ideal storage environment for this carbon-rich biomass, by preventing carbon from being released back into the atmosphere during decomposition.
“This natural preservation capability, along with the amount of plants growing around the Black Sea, led Rewind to explore the potential of storing surplus biomass in oxygen free environments for permanent carbon removal,” he says.
A ‘nature-aligned’ solution
A former software engineer with a BSc in Physics and Computer Science, Amar turned his attention to climate matters some years back, following the sale of a big data startup to Google. He co-founded Rewind as a “nature aligned” solution, which seeks to emulate natural carbon storage processes with minimal energy input. The Israeli firm aims to prioritise sustainability by ensuring biomass is responsibly sourced – collected from material that would otherwise be incinerated, or from areas where biomass levels are maintained or increased – and stored.
“The cost-effectiveness of the method is by design, relying on transportation energy only, which surprisingly is very efficient, much more efficient than thermal energy,” says Amar. “Energy is directly related to costs as well as to carbon emissions, and Rewind’s method emits on average only 10% of the carbon it removes.
“In other words, Rewind’s method results in 90% carbon removal efficiency, and some of Rewind’s projects, where biomass and storage are co-located, reach 98% efficiency.”
But does the science stack up? Observing the wrecks of sunken galleons is one thing, but transforming it into an efficient, eco-friendly carbon capture solution is quite another.
“From day one, we knew that a carbon removal solution, especially one that aims to leverage the marine environment, must be backed with solid science,” says Amar, who adds that the firm has conducted PhD level research projects to demonstrate the permanence and environmental safety of its methods, and engages regularly with a dedicated scientific advisory board, and the academic community, to review and validate its work.
Two key initiatives the company is “particularly proud of” include the Framework Protocol for Marine Terrestrial Biomass Storage (MTBS), which outlines procedures, risk mitigation, and monitoring strategies for safely storing biomass in the Black Sea and was peer-reviewed by marine carbon removal experts, and the MACS (Marine Anoxic Carbon Storage) Workshop, co-hosted with GeoEcoMar, which brought together 35 researchers from 25 institutions across 13 countries.
“The workshop focused on how the group can create an international collaboration to advance MACS,” Amar notes.
Marine environment
The scalability of Rewind’s solution is based on responsible growth, given that its solution interacts with the marine environment – the company needs to make sure that it follows “local and international laws and regulations relating to protection of the marine environment,” says Amar.
“The first step of MACS in the Black Sea is to place 100 tonnes of biomass on the oxygen free seabed and to carefully monitor the biomass and the marine environment for changes in chemical and biological composition,” he says. “After reviewing the results and validating the safety criteria with the local and international scientific and environmental communities, the next step of scale can commence, sequestering 1,000 tonnes and continuing the same monitoring regime.
“This process will continue scaling similarly, increasing the volume by an order of magnitude at every step, while ensuring and validating environmental safety.”
The company is confident that this stepwise model will ensure environmental safety while allowing significant growth in carbon sequestration capacity over time. Given that the Black Sea contains approximately 540,000 gigatons of water, the potential addition of one gigaton of biomass (around 2 cubic kilometers in volume) would be negligible in terms of spatial and environmental impact.
“In more scientific terms, the particular chemical composition which should be monitored is sulfide and methane production in the Black Sea, both of which are core components to Rewind’s MRV [monitoring reporting and verification] technology,” says Amar.
“When it comes to biomass, the annual growth of plants in agriculture and forests around the Black Sea surpasses a gigaton and provides ample opportunity for sustainable biomass sourcing at these scales.”
Growth prospects
Looking ahead, Rewind faces two main challenges in ensuring its carbon sequestration model is fit for the future. The first is regulatory compliance, including conducting environmental assessments and working with stakeholders. “To address the first challenge, Rewind actively collaborates with governments, local communities, and scientific organizations to build trust and ensure that all operations meet environmental and safety standards,” says Amar.
The second challenge, meanwhile, involves gaining the support of carbon markets. To address this, Rewind works “with the leading – both private and governmental – organisations for setting carbon removal standards, and engages with potential buyers to build reliable demand for Rewind’s services.”
Rewind is also actively expanding beyond the Black Sea to identify additional oxygen-free environments suitable for biomass storage, such as marine sediments and in deep underground mine chambers.
“Rewind is committed to expanding its impact and scale globally and has several projects under these methodologies in different stages of development,” Amar adds.
Who knows what the ancient mariners of yesteryear might have made of it all?
Learn more about Rewind at www.rewind.earth.
