Direct capture of atmospheric carbon dioxide (DAC) holds the promise of helping to achieve global warming mitigation goals. However, many DAC technologies are hindered by high cost and inefficiency. The company RepAir Carbon (Yokne-am Illit, Israel; www.repair-carbon.com ) recently launched a prototype of their DAC technology, which is based on a continuous electrochemical process that reduces energy consumption and costs compared to other DAC solutions. Similar to a fuel cell, the RepAir process uses two electrodes separated by a selective polymer membrane. Cells can be "stacked" to multiply carbon removal capacity. "Atmospheric air is drawn into the cathode, where an electric current generates hydroxide ions that bind to CO molecules ₂ and form carbonate and bicarbonate ions. Only these ions pass through the membrane to the anode, where the binding process ends, hydroxides are consumed and pure CO gas ₂ is sucked out," explains Amir Shiner, CEO and co-founder of RepAir Carbon. Unlike other DAC processes that must run in discrete batches, RepAir technology can run continuously because the cell is designed so that the polarity of the electrodes and the air inlet are switched every few hours. The technology can be fully run using renewable electricity without an additional heat source, resulting in 70 % lower energy consumption compared to other DAC processes, the company says. (Mary Page Bailey)