By Michael J Coren,Michael J Coren

Solar power is nothing new under the sun. Plants have been doing it since photosynthesis first evolved more than 3.5 billion years ago.

But scientists are taking a cue from the experts by borrowing this ancient photosynthetic machinery to derive our own truly green solar panels that trade toxic chemicals for the more natural compounds in leaves and grass clippings. If successful "this intricately organized photosynthetic nanocircuitry ... carries the promise of inexpensive and environmentally friendly solar power," reports Nature.

The secret is a photosynthetic pathway called Photosystem 1 (PS1). This pigment-protein membrane complex is "at the heart of the Earth's energy cycle." Sunlight goes in and energy comes out, usually in the form of plant sugars and carbohydrates.

Scientists discovered about 40 years ago that a key PS1 protein converting sunlight to energy in spinach continued to work outside the plant's cells. For decades, they have been experimenting with ways to make PS1 work as well for solar panels as well as it does for plants.

They're not there yet, but researchers have started making real progress. Scientists at Vanderbilt University managed to integrate the PS1 protein into solar panels, achieving much higher efficiencies than "biohybrid" cells, about two and a half times more current than previous versions.

The only problem with this and other biohybrid cells is that they are radically underpowered. Despite the efficiency gains, conventional panels generate several orders of magnitude more electricity per unit area. But scientists are inching closer to parity. The process of creating PS1 substance is now so simple that "virtually any lab could replicate it, including college or even high school science labs," reports MIT, and the technology only needs another tenfold or so increase in efficiency to become useful.

Once the technology hits that mark, says MIT researcher Andreas Mershin, you can starting thinking about ways to mix up solar cells in a plastic bag by just using a few chemicals and grass clippings. Now, that's renewable energy.

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