Equatic has developed an electrolytic process for atmospheric carbon dioxide removal that leverages the size and scale of the oceans. The process stabilizes carbon dioxide permanently in the form of dissolved bicarbonate ions (in seawater), and in the form of solid mineral carbonates. Moreover, the process produces hydrogen – a green fuel – as a co-product that generates revenue and clean energy.
Anew California-based startup is trying to take on climate change by simultaneously taking carbon dioxide out of the ocean and air while creating hydrogen as an alternative fuel. Boeing has already inked an agreement with Equatic.
Equatic has developed an electrolytic process for atmospheric carbon dioxide removal that leverages the size and scale of the oceans. The process stabilizes carbon dioxide permanently in the form of dissolved bicarbonate ions (in seawater), and in the form of solid mineral carbonates. Moreover, the process produces hydrogen – a green fuel – as a co-product that generates revenue and clean energy.
Process
The oceans are the world’s sink of CO2. In fact, 30% of annual CO2 emissions are absorbed by the world’s oceans. Equatic leverages a first-of-a-kind electrolytic approach that removes CO2 equivalents from the ocean, in turn allowing the ocean to remove more of it from the atmosphere.
The process exploits the ocean-air equilibrium of CO2 and the enormous abundance of calcium and magnesium ions in seawater. By coupling carbon dioxide removal and generation of hydrogen as a green fuel it achieves two objectives essential for a de-carbonized economy:
It immobilizes CO2 permanently in the ocean, as dissolved bicarbonate ions (in water), and in the form of solid mineral carbonates.
It produces hydrogen, a green fuel that can replace fossil fuels, to thereby eliminating any further CO2 emissions.
As both outputs share the same equipment and capital investment, Equatic can achieve unique cost, another enabler of the decarbonized economy.
electrolytic process, developed by scientists at UCLA’s Institute for Carbon Management, is based on continuous (flow-through) electrolysis of sea-water to permanently lock CO2 within stable carbonate solids and in the form of dissolved inorganic carbon (DIC). It is this permanent “lock-up” that allows the ocean to draw-down additional CO2 from the atmosphere.
The removal of CO2 from seawater is coupled to the generation of green hydrogen. The natural alkalinity of seawater is restored by dissolving alkaline rocks prior to discharge, thereby keeping the natural composition of sea water intact.
Seawater has contained dissolved inorganic carbon for millions of years, and is in effect oversaturated with respect to calcium carbonate (as exemplified by the stability of sea shells). The Equatic process exploits this fact to immobilize, carbon dioxide in the oceans for tens of thousands, if not millions of years.
The Implementation
The technology is being demonstrated with two pilots, one at the Port of Los Angeles and a second one in Singapore. Each of these first-of-a-kind plants removes ~100 kg of CO2 per day. Equatic has designed and built novel, two-chamber, flow-through electrolytic reactors and is validating and optimizing their performance with the two pilots. The pilots also verify that CO2 is being effectively removed from the atmosphere.
We use mass balances to quantify carbon removal
Total Carbon Removal CO2e＝Drawdown CO2e－Emissions CO2e
where, Emissions CO2e includes the total embodied CO2 emissions from material and energy use (e.g., the grid emissions factor of electricity, electrode fabrication, etc.), and:
Drawdown CO2e＝Equatic Dissolved, CO2e ＋Equatic Solid, CO2e－Evasion from seawater
The CO2 sequestered as dissolved HCO3– and CO32– ions, and solid carbonates can be quantified unambiguously by weighing the masses of Mg(OH)2 and CaCO3 produced, and multiplying these masses by a carbon removal factor, as follows (in units of g CO2 per m3 of water processed):
Equatic Dissolved, CO2e (g CO2/m3 water) = mass % Mg(OH)2 × total mass of solids (g/m3 water) × (1.7 mol CO2/mol Mg(OH)2) × (44.01 g CO2/mol CO2) × (1 mol Mg(OH)2/58.3197 g Mg(OH)2)
Equatic Solid, CO2e (g CO2/m3 water) = mass % CaCO3 × total mass of solids (g/m3 water) × (1 mol CO2/mol CaCO3) × (44.01 g CO2/mol CO2) × (1 mol CaCO3/100.0869 g CaCO3)