Most of us think of solar power as coming from glass panels on rooftops, and increasingly large arrays in the middle of some sun-drenched desert. Now it can come from green, slimy ponds and bioreactors filled with algae that soak up the rays to make oil.

Some species of algae contain as much as 50% oil, and out-produce other biofuels. An acre of soybean produces around 70 gallons of biodiesel. The same area of corn makes roughly 420 gallons of ethanol. Algae can produce about 5,000 gallons of biodiesel per acre. Not too shabby!

Another plus is that algae don’t compete with our food supply as other biofuels can. No exorbitantly priced corn tortillas just to fill our gas tanks!

As if that’s not enough to make you cheer, algae thrive on things that are either free, or considered pollutants that need treating - sun, CO₂ and compounds commonly found in wastewater. Team algae production up with power plants, and suddenly a CO₂-emissions problem becomes an oil boon.

A number of experimental algae biodiesel production plants have been built. Last year New Belgium Brewing Company in Colorado installed test systems to scrub its annual 5,000 metric tons of CO₂ emissions. Several power companies around the country gather data from systems treating CO₂-laden flue gas.

Commercial algae-based biodiesel production is several years away, however. A number of problems plague the nascent industry, not least of which is that algae are finicky. They need the right temperature, pH and salinity. Unlike us, they don’t like much oxygen, which is one of their own waste products. Other microorganisms can invade their cultures. Two California companies, Solazyme and LiveFuels, are developing hardier strains of algae that also contain more oil.

Several other firms are forging the way for commercial production. GreenFuel Technologies started as the brainchild of MIT Chemical engineer Isaac Berzin. While working on an International Space Station project in the 90’s he came across references to algae with high oil content. He designed and installed a system on MIT’s 20 megawatt power plant that removed 40% of the plant’s CO₂ emissions, and 86% of its nitrogen oxides (the orange smog over cities, and the main ingredient needed to make ground level ozone, which causes respiratory problems).

This year, GreenFuel completed tests of its patented technology at Redhawk Power Station near Phoenix, Arizona. The technology addresses one of the tricky aspect of algae production: delivering light to the algae. You’d think that would be simple in a place as sunny as Arizona. However, open pond systems, while inexpensive to install, are not very efficient as light does not penetrate very deeply. Stacked tubular systems increase surface area exposed to light. GreenFuel’s technology is apparently a matrix system, which they claim increases efficiency still further. Having field-tested the technology, GreenFuel is “in active negotiations with several potential partners to deploy its first commercial installation,” according to its website.

Late last year Green Star Products of Chula Vista, California, signed an agreement to deliver biofuel reactors to South Africa with production capacity of 900 million gallons of biodiesel per year – four times the US output. The reactors initially use sunflower seeds, but will transfer to algae. The firm has completed successful tests of algae production facilities in Montana.

Solix Biofuels, a Colorado start up founded in 2006 to develop commercial-scale algae biodiesel, and Aurora Biofuels of California, are both developing improved harvesting and extraction methods.

And the list of companies in the algae-fuel business goes on. They’re approach to boosting productivity may be different, but what they all have in common is their zeal for algae. They see it as the answer to the world’s increasingly limited oil supply. Chief among the starry-eyed is Green Star Products President, Joseph LaStella, who said recently, “Today we are closer than ever before to solving our energy and global warming issues. The solution is ‘ALGAE’, one of the oldest forms of life on Earth.”

Be that as it may, one thing’s for sure. What only a couple of years ago sounded as viable as fusion – although, maybe we shouldn’t snigger too loudly at that, either, as Britain recently announced that it is designing a fusion machine – now sounds full of promise.