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Wiser Power Plants

A breakthrough water-repellent coating aims to drastically reduce carbon dioxide emissions in power plants. 



With over 62,500 power plants operating around the world, the balance between global energy production and environmental sustainability has become more crucial than ever before. Thanks to a new technology, steam-driven power plants, which generate more than 85 percent of the world’s power, can be transformed to ensure cleaner energy production, reduced water consumption and less carbon emissions.

Professor Kripa K. Varanasi

Kripa K. Varanasi, associate professor of mechanical engineering at Massachusetts Institute of Technology, and his colleagues at DropWise Technologies Corp., have developed a breakthrough water-repellent coating that makes power plants more efficient and environmentally sustainable, while saving millions of dollars in annual costs.

Global carbon emissions from fossil fuels have radically increased over the past 100 years. According to the U.S. Environmental Protection Agency, emissions increased over 16 times between 1900 and 2008, and 1.5 times between 1990 and 2008. Professor Varanasi says that applying DropWise’s new coating at just one steam-driven power plant would reduce yearly emissions equal to taking 4,000 cars off the road. Power plants using the new coating could also save up to half a million dollars per year on fuel cost. “From Day 1, our team’s goal was to focus on improving an existing process, rather than reinventing the wheel,” says Professor Varanasi. “We saw a huge opportunity to realize efficiencies that would have a profound effect on global energy.”

All steam-driven plants are powered by condensers. Fuel—nuclear, coal, natural gas or solar thermal—is burned to produce steam that spins a turbine. As steam surfaces, it is suddenly cooled down and condensed back into water, generating a powerful suction force that helps propel the turbine and create energy.

During the process, however, it is common for a film of water to build up on the walls of the condensers, slowing the cooling procedure and making the method less efficient. A water-repellent coating could reduce the inefficiency in the steam condenser. “Solving this materials challenge was our first obstacle,” says Professor Varanasi. “We’re talking about a coating that is 2,000 times thinner than a piece of paper, yet strong enough to withstand years of harsh usage in a power plant.”

After years of testing at MIT’s research labs, DropWise is now prepared for the commercial launch of the product. The startup was officially formed in late 2014, and has been busy lining up strategic investors. DropWise will deploy the water-repellent coating through a patented vapor-phase process, now capable of forming a durable bond on a variety of complex industrial parts.

Professor Varanasi estimates that power plants would start using the coating within the next two years, which would immediately deliver a 3 percent efficiency gain in the plants’ output. Thermal power plants are the second largest consumer of water on the planet, and the improvement in condenser efficiency would have a huge effect on global energy production and environmental sustainability.

DropWise’s unique coating could significantly improve the global energy outlook. Professor Varanasi says DropWise’s goal is to see their product make the world a better place. “We don’t want to stop at writing papers about our research; we want to scale things up and completely change the paradigm.”


Jason Chiang is a freelance writer based in Silver Lake, Los Angeles.