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Spaceship Earth: Getting Energy from Algae

By: Dr Gareth Evans - Updated: 25 Aug 2012 | comments*Discuss
 
Algae Energy Renewable Clean Green

There’s nothing new about the idea of getting energy from algae. It has been known for years that some kinds of these simple plants can yield over 1,500 gallons of oil per acre – that’s more than three times the amount that can be produced by palms and a staggering 40 times more than soy. The difficulty in making the most of this huge potential has always lain in the massive demands on land and resources that it would take, not to mention the costs involved in constructing the necessary algal ‘bioreactors’ and then running them.

That could all be about to change, however, if a revolutionary new approach to algal oil production being developed by America’s space agency, NASA, lives up to expectations.

Spaceship Earth

Ask any Star Trek fans about the weapons aboard the Starship Enterprise, its warp drive or the transporter system and the chances are they’ll tell you all you want to know – and more! Ask them about the toilets, on the other hand, and you’ll probably have them stumped, but as NASA realised a long time ago, how you deal with sewage is going to be one of the key factors in making manned missions into deep space possible in the future.

It was pondering this problem which inspired the project, named “Sustainable Energy for Spaceship Earth”, and ultimately led the way to the new method of clean energy biofuel production from algae, which could benefit us all, not just future generations of astronauts. Best of all, it also helps to remove carbon dioxide from the atmosphere and reclaim valuable nutrients from the poo – cleanly and efficiently.

How Does It Work?

Despite its ‘rocket-science’ origins, the idea is surprisingly simple. In the words of the project’s leader, Jonathan Trent, it is “a large plastic bag” filled with sewage, and floating in the sea, although the fabric of these particular bags is a little more complicated than your average bin-liner, of course. They’re technically known as forward osmosis membranes and created from a purpose-made, semi-permeable material which keeps sea water out, but allows gases and freshwater to escape.

Inside, a freshwater alga, officially known as Botryococcus braunii, uses the nutrients from the sewage to grow, taking carbon dioxide from the air to photosynthesise and making oxygen as a natural by-product, like other plants. Unlike most other plants, however, the algae produce special oil-rich cells within themselves, and it is these which make them so attractive as a source of harvestable energy, since the oil can be refined to provide ‘green’ substitutes for the likes of petrol, diesel and aviation fuel.

Once the sewage has been treated, the algae are harvested and the oil reclaimed for use – but it doesn’t stop there. Their remains could also be turned into fertiliser, animal food supplements or even cosmetics, while the bags themselves can be recycled for horticultural uses. Managing limited resources very carefully is not just for astronauts!

A Commercial Reality?

Growing energy-producing algae at sea isn’t simply a gimmick; there are three very sound reasons for doing so. Firstly, it obviously gets around the previously mentioned problem of competition for available land, which is always a major stumbling block for ground-based biofuel production. It’s very hard to justify growing energy crops for the industrialised nations’ cars and planes when so much of the rest of the world is hungry. Secondly, the sea itself acts as a buffer, shielding the temperature inside the bags from the sort of big fluctuations often seen in similar systems on-shore. Finally, tide and wave action adds up to a lot of free mixing, ensuring that the contents of the bags remains well mixed without needing costly pumps or a power source.

All of this perhaps sounds a bit too good to be true, and you might be forgiven for thinking that it’s another great idea destined to be forgotten in a couple of years, when the next new scheme comes along – except that it’s poised for commercial use. According to the aptly named company, ‘Algae Systems’ the much-heralded potential of algae as a renewable, clean energy source will soon begin to become a reality, with the arrival of the world’s first Offshore Membrane Enclosures for Growing Algae (OMEGA) system. Company founder, Matthew Atwood, has big hopes for what he calls the “transformational powers” of OMEGA, which he believes will bring huge benefits in terms of providing both cheap local energy and jobs. After all, as NASA’s deputy director of the New Ventures and Communication Directorate, Lisa Lockyer points out, the agency does have “a long history of producing highly successful energy conversion systems and innovative life support devices.”

So far at least, it’s all looking good, Houston!

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