Power plants are still the single largest source of carbon dioxide (CO2), a greenhouse gas that traps heat and makes the planet warmer. According to the U.S. Environmental Protection Agency, coal- and natural gas-fired plants were responsible for a third of U.S. greenhouse gas emissions in 2012.
At TreeHugger we used to comment frequently on ways to capture greenhouse gases and (ostensibly) reduce global warming. Around 2009 there were plenty of strategies and talk about how carbon capture was definitely going to be a tool to slow global warming.
Carbon capture and sequestration (CCS) was a very real idea but a very expensive proposition for power companies, and after some spendy pilot programs - like at the Mongstad plant in Norway - the idea started to fade away.But not entirely. At the University of Illinois, for example, one project recently celebrated sequestering one million tons of CO2.
And a recent Harvard team has reported on materials that enable a safer, cheaper, and more energy-efficient process for carbon capture at power plants. The new materials are based on good old kitchen-grade baking soda. You know - in the orange box with the arm and the hammer.
Otherwise known as sodium carbonate, the baking soda achieves an order-of-magnitude increase in CO2 absorption rates compared to the type of absorbing materials currently used.
These materials, based on caustic amine solvents, separate CO2 from the flue gas escaping the power plant's smokestacks. But they are expensive, result in a significant reduction in a power plant's output, and yield toxic byproducts.
The new technique developed by the Harvard team encapsulates the baking soda and is called microencapsulated carbon sorbents (MECS). While currently-used amines break down over time, carbonates have much better staying power.
"MECS provide a new way to capture carbon with fewer environmental issues," said Roger D. Aines, leader of the fuel cycle innovations program at Lawrence Livermore National Laboratory and a co-lead author. "Capturing the world's carbon emissions is a huge job. We need technology that can be applied to many kinds of carbon dioxide sources, with the public's full confidence in the safety and sustainability."
With the EPA proposing rules that would require reduced emissions from new plants, the cheaper MECS process for capturing greenhouse gases may bring CCS back to life, and help stall climate change.