What if we could turn carbon dioxide into electricity?

Jul 24, 2013 - By Janet Fang - Smartplanet.com

Emissions from smokestacks typically include between 5 and 20 percent of carbon dioxide. What if we could convert that greenhouse gas into electricity? A new technique from Dutch researchers hopes to do just that. ScienceNOW reports.

Electric power-generating stations worldwide release about 12 billion tons of CO2 annually from the combustion of coal, oil, and natural gas; home and commercial heating produces another 11 billion tons.

Sure, they contribute to climate change, but CO2-ridden plumes could also be a new source of electrical power, according to Bert Hamelers and colleagues from Wetsus, the Dutch center of excellence in sustainable water technology. Usually, it all just goes to waste.

To transform trash into treasure, the team used a device called a capacitive electrochemical cell:

Built roughly like a battery, the cell has two electrodes — one surrounded by a membrane that allows hydrogen ions to flow in and out, and the other that does the same with bicarbonate ions, produced when carbon dioxide is bubbled through water.

They developed a two-stage process to harvest the chemical energy in CO2 emissions.

1. They pump water flushed with CO2 through the cell, which causes the hydrogen and carbonate ions to flow into their respective electrodes. This separation of ions charges the cell and drives an electrical current.
2. Once the electrodes have absorbed as many ions as they can, the researchers begin to pump air-bubbled water through the cell. This drives the ions out of the electrodes and back into the cell.
3. By constantly alternating between these two stages, the cell can produce electrical power.

The new process could generate about 1,570 terawatt-hours of power each year by tapping into existing CO2 emissions from power plants, industrial smokestacks, and residential heating worldwide.

That’s about 400 times that produced by the Hoover Dam. And like other hydroelectric power facilities, the electricity would be produced without adding to global carbon dioxide emissions, Hamelers added.

The work was published in Environmental Science & Technology Letters today.

[ACS news release via ScienceNOW]

Image: Curran Kelleher via Flickr