You are here

Can Pond Scum Save the World

Friday, April 8, 2011

In labs around the world, plastic bags of green water are quietly basking in sunlight. The water’s filled with what’s commonly known as ‘pond scum’. Its official name is green algae- a tiny, unicellular organism found in ponds, rivers and oceans worldwide. It looks slimy, murky and just plain yucky. In spite of this, scientists worldwide are furiously trying to figure out how to best grow and process it. If they succeed, they might just save the world.

When I first heard about this massive effort, I thought to myself “Why”? Why is so much effort going into something so apparently mundane? 

A quick web search later, I had my answer. Put simply, green algae has an unparalleled ability to absorb and store energy. If scientists can harness this power, they just might be able to create a clean alternative to gasoline and other fossil fuels. This potential that has attracted hundreds of researchers and billions of dollars of investment to date. 

Green algae is currently one of the hottest prospects in alternative fuels. Green algae is an example of a biofuel — a fuel made from a biological material like corn or sugar cane. What gets scientists — and armchair observers like myself — so excited about it is its tantalizing combination of properties. 

Given the right conditions, green algae grows so quickly it doubles its mass overnight. Just try and get corn or any other land crop to do that! As it grows, green algae converts sunlight into oil stored inside its cell walls. If scientists can efficiently extract and process this fuel, they’d generate vast amounts of gasoline and diesel. Critically, the process would be virtually pollution free.

If just less than half a percent of the world’s land was devoted to growing green algae, it would produce enough oil to replace fossil fuels entirely. But only if we can extract it efficiently.

This ‘if’ is where the sticking point lies. Research into green algae is still in its infancy. Only tiny amounts of biodiesel fuel have been produced from it so far. The technology is unproven and may never pan out. 

Green algae growth is highly sensitive to surrounding conditions and the process of extracting oil from it is complex and unperfected. But, with billions of dollars of investment to date, a dwindling supply of fossil fuels and global climate change, the stakes couldn’t be higher.

If green algae biofuel can be produced on a large scale, the pay-off would be immense. By 2030, it just might be providing a significant fraction of the world’s energy, helping to free us from the shackles of fossil fuels. This prospect has attracted hundreds of the world’s smartest scientists, engineers and entrepreneurs, not to mention significant support from governments worldwide.

Who knows, in 2030 you and I just might be filling up our cars with pond scum.


Written by: Damian Pope

Damian has a PhD in theoretical physics from the University of Queensland in Australia. He also has extensive experience communicating science to the public and is currently the Senior Manager of Outreach at Perimeter Institute for Theoretical Physics.