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The battery that captures CO₂

A new device able to generate energy while reducing emissions.

by Chris Dalby
6 min read
by Chris Dalby
6 min read

In late 2019, researchers from Massachusetts Institute of Technology (MIT) announced a new method to trap carbon dioxide from the air even when present in very low concentrations. This was an attention-grabbing mission statement given the potential applications of carbon-trapping in the fight against climate change. MIT's track record as a conveyor belt of new green technologies speaks for itself, but can this latest development live up to the hype?

How does it work?

In October 2019, seemingly every media outlet from PBS to Mashable showcased the discovery. Officially named a "faradaic electro-swing reactive adsorption for CO2 capture" by creators Sahag Voskian and T. Alan Hatton, the technique is composed of a large battery bearing electrodes that capture carbon dioxide from the air above them as the battery is being charged. Essentially, the charging of the battery causes a chemical reaction that attracts carbon dioxide from the atmosphere. The CO2 immediately surrounds the device, a process referred to as direct air capture.
What has scientists excited about the potential of this creation is that the electrodes have been specially designed to attract carbon dioxide and react with its molecules, even when present in relatively small amounts. Another advantage is that the device does not need any sort of specific conditions to work. “All of this is at ambient conditions—there's no need for thermal, pressure or chemical input. It's just these very thin sheets, with both surfaces active, that can be stacked in a box and connected to a source of electricity", Voskian told MIT News.
The battery currently works with carbon dioxide at 400 parts per million and can then release the CO2 into other streams removing it from the atmosphere. And Voskian is confident that scaling up won't be a problem. As he explained to PBS, an area the size of a football field with stacks of batteries "tens of feet high" could remove 200,000 to 400,000 metric tons of CO2 a year.

CCS concerns

Renewable energy sources may be on their way to replacing fossil fuels as the driving forces of global energy, but scientists have long argued that their development must be accompanied by a solution to capture and store carbon emissions already produced. In order to meet recommendations by the Intergovernmental Panel on Climate Change (IPCC) to keep global warming at just 1.5°C, the IPCC's own research found investments in low-carbon energy technology would need to increase by 500% between 2015 and 2050.
Quite a few major failures have stopped this from happening, however. In 2007, the UK launched a major CCS investment plan to encourage existing power plants to trap carbon dioxide and store it in underground reservoirs. Ten years and US$200 million later, there was nothing to show for it. Voskian and Hatton's idea has people excited, as their battery design is versatile enough to be tailored to the specific carbon capture and storage requirements of specific industries.

The MIT's headquarters in Massachusetts

Commercial applications

While many carbon capture projects have never moved past the design phase, the MIT team is confident about finding commercial avenues, and has already created a private company to tap into this market. At the moment, the device works by removing CO2 from a stream of air passing over its electrochemical cells. While it is not a panacea yet, there are clear industrial settings in which it could be used to great efficiency. One such application, reported The Engineer, could be in a power plant continuously producing exhaust gas. Two sets of the cells could theoretically be set up in tandem—the first capturing carbon from the exhaust until it needs to discharge it, and the second taking over at that moment. This could create a constant loop of carbon capture and discharge.
Voskian has also thought of another number of applications. One could be for the carbonation of soft drinks, with captured carbon dioxide injected into the water stream to create fizz inside bottling factories. Another could be for agriculture, for when farmers need carbon dioxide to nourish plants in greenhouses. Even renewable power plants, such as wind and solar, could benefit by using the battery system to use any excess energy they produce to capture carbon. “That's one of the nice aspects of this technology—that direct linkage with renewables", explained Jennifer Wilcox, a chemical engineer at Worcester Polytechnic Institute, to PBS.

Proving market viability

As always, one must be cautious when placing too much hope in a single technology, especially since Voskian and Hatton's carbon capture system has yet to prove its worth on a grand scale. Richard Newell, CEO of Resources for the Future, described it as a great breakthrough, "but the distance between showing something in the laboratory and then demonstrating it at a commercial scale is very big".
Nonetheless, the two scientists believe in the commercial applications enough to have launched a startup, named Verdox, focused on its development. They have even tentatively priced their services at US$50-100 per metric ton of carbon dioxide captured. With 2020 shaping up to be a bullish year for sustainable finance initiatives and with predictions that the price of carbon capture will continue to go down in the next few years, they may be hitting the market at just the right time.

The author: Chris Dalby

Energy and political journalist with experience covering politics, energy, oil and gas, mining, finance, business, Latin America, China, and the Olympics.