Reducing carbon with algae at local power plant

BOONE COUNTY, Ky. (Josh Knight) — While algae might be a nuisance in your fish tank, researchers think it might be part of the answer to slowing greenhouse gas emissions at power plants, and ultimately climate change. As global carbon dioxide levels continue to go up, more mandates are likely to come down and power plants need solutions.

About half of the electricity produced in the United States is done at coal fire plants like the Duke Energy East Bend Station in Boone County. That process releases gas into the air and now it’s being trapped and used to grow algae. Then the algae can be turned into other important things.

“We’ve made jet fuel, we’ve made renewable diesel fuel,” said Biofuels Research Engineer Michael Wilson with the University of Kentucky. Going from algae to jet fuel may sound like a big jump, but making new materials out of coal burning byproducts has been going on for years.

Doug Durst, Technology Development Manager with Duke Energy, explained the majority of what can be seen at a power plant isn’t actually generating electricity. The coal burning and the spinning turbine are housed in one area and the rest is all environmental equipment. Over the years, as environmental laws are passed, new equipment is added that traps different chemicals.

At this plant, things like sulfur, ash, and mercury are no longer released into the air, but it goes one step farther. The byproducts created while capturing these chemicals can sold and used in concrete and even drywall manufacturing. “The flue gas coming from a coal fire plant, ten percent of it is CO2,” Durst said.

Nitrogen is the most abundant gas coming from the stack (also the most abundant gas naturally found in the atmosphere) and the part you can see is predominantly water vapor. The University of Kentucky and Duke Energy have partnered on this project to capture the flue gas and grow algae.

Algae research is happening around the world, but this is the only place in the country where the team is tied into an actual power plant. The gas coming out the stack is actually the same gas running through the tubes. “We’ve got it in an applied nature at a pilot level and now we’re just going to be improving efficiencies,” said Wilson. Algae are growing in clear tubes several feet tall.

“Algae are microscopic water balloons, dissolved and very diluted in water,” said Wilson. Like all plants, they grow and make food using carbon dioxide, sunlight, and water through photosynthesis. Inside the tubes with the flue gas, they have all the carbon dioxide they could want. Wilson said, “it’s a Kentucky alga, readily found in many of the waterways around here. We’re harnessing its ability to do photosynthesis very, very fast. So it’s consuming CO2 as it grows.”

At this point, the amount of gas being diverted is miniscule, “It’s the equivalent to a leak in the duct work,” said Durst. However, they’re proving it’s possible. “They call it research for a reason, there’s a ‘re’ in research, so you’re going to do it over and over again until you find a way that works,” Wilson said.

In order to scale this up, to take on all of the flue gas, it would be a much bigger operation. “We’re talking hundreds of acres, potentially square miles. That’s just a factor of how quickly the organism grows and how much CO2 is being generated,” Wilson said. “If you look at that from a positive side, you could say that’s an awful lot of biomass we’re producing, an awful lot of final product,” he added. “They can double every day. So you could potentially take a harvest out of this reactor, if the growth conditions are right, every day,” Wilson said.

The algae biomass can be used to make anything from bio-fuel, to bio-plastics, foods and pharmaceuticals, allowing power plants to grow green, go green, and even make some green. This is still experimental, but Wilson believes that algae are the answer to reducing carbon emissions. “It can be done, but when it is done, it will be done in a big way,” said Wilson.


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