microscopic photo of green algae

Algae is the fastest-growing plant in the world, capable of doubling its mass in 2-3 hours.

If you have ever owned a fish aquarium or a swimming pool, green algae has been a problem for you at some point.  It takes hold on every surface and even exists as free-floating colonies.

But don’t dismiss the green stuff as merely an annoyance.  Algae are now being used to filter greenhouse gasses from industrial power plants, reducing CO2 emissions by 80 – 90%.

Scientists at MIT had been using the little green plant to filter carbon dioxide emissions by pumping waste gasses into pipes filled with algae and water.  Green Fuel Technologies, the now-defunct MIT start-up, has led the way to more research and experimentation using the green triangle system to control the amount of C02 emissions coming from industrial power plants.

To facilitate photosynthesis, the “green triangle” pipes are built on rooftops in space-saving upright triangles, allowing the algae to receive just the right amount of sun exposure.

green triangle diagram

The green triangles are fed carbon dioxide and mono-nitrogen oxides to produce more algae and clean the air before being released into the atmosphere.

Each year, industrial plants around the globe produce over 33 metric tons of C02, 50% of which ends up in the atmosphere, contributing to the phenomenon known as global warming.  Industrial plants in the U.S. are required to install “scrubbers” in their emissions towers, which are basically water filters that remove particles from the air.  But once the water removes the waste particles from the air, it is often dumped back into rivers, lakes and streams, contributing to groundwater pollution.  By using traditional scrubbers, power plants are not eliminating the problem, they are just moving it somewhere else.

The solution:  employ algae to “eat” the waste.  Algae not only converts emissions waste into an ecologically safe byproduct, the leftover “algae powder” can be used to make bio-fuel or

smoothies, your choice.

Most types of algae grow best when there is lots of light, and some types of algae are able to convert carbon dioxide and/or mono-nitrogen oxides (nitric oxide and nitrogen dioxide) into energy to grow and reproduce.  So the folks at MIT gave their algae plenty to eat.  Waste gas from MIT’s 20-megawatt cogeneration plant was pumped into the tubes, and the algae would go to work converting the CO2 into oxygen and nitrogen, byproducts of photosynthesis.

dried green algae

Dried algae is the byproduct of green algae triangles and can be used as bio-fuel, animal feed or making smoothies.

Algae grow fast – as in doubling mass every few hours fast.  So, the more waste gasses are pumped through the algae tubes, the more the algae “eats”.  MIT’s green triangles were shown to reduce CO2 emissions by 82 percent on mostly sunny

days and 50 percent on cloudy days.  Although they are not yet cost effective for widespread use, research continues in an effort to make the green triangle system more efficient in hopes of producing a sustainable filtration system for industrial power plants and a good source for farm-free bio-fuel.

Watch a video to learn more about how the green triangles work.

By India Stone

Photos from GreenEnergyTV and GreenFuel Technologies.