Mimicking Nature: Power Generating Artificial Trees

August 28, 2008 – Vol.13 No.23

MIMICKING NATURE: POWER GENERATING ARTIFICIAL TREES.

If there’s a problem with solar energy, it’s that it takes up too much space, too much surface area, too much real estate for the amount of power produced. For a solar power plant to generate a significant amount of electricity – perhaps hundreds of megawatts – to compete with a conventional power plant vast acreage is needed. Land costs money; money that adds to the cost of solar energy being generated. The cost, or value, of real estate on which to build large solar systems may limit the construction of large scale solar power plants to areas where real estate is cheap, or to roof tops where a solar system’s footprint can be only as large as the area of the building.

Manmade solar technologies need, mostly, direct sunlight to work optimally, which is why they need so much space; Solar needs a direct view of the daytime sky, as it were. Solar doesn’t work so well in the shade.

But that’s manmade solar devices. Nature has its solar devices too, we call them plants. While plants don’t convert sunlight to usable electricity, they do use the energy in light to convert water and air into cellulose, the structure of the plant. This is considerable work in itself.

Take for example the grandaddy of plants, the tree, a hardworking solar energy conversion device. The leaves on a tree absorb sunlight, yet not all leaves are in direct view of the sun. Some leaves are in the shadow of other leaves, but they still thrive. (When you get a chance, take a gander at the leaves on your favorite tree and witness this phenomenon.)

How does nature do this? How does nature ensure that the leaves deep with the canopy of a tree get enough sunlight to continue working, growing? Nature has designed tree branches to strategically keep leaves in the sunlight. There’s space between leaves to allow light through to those beneath. Leaves reflect light onto each other. Leaves can be slightly translucent, allowing some light to filter through for other leaves to benefit. And leaves seem to work in indirect and reflected sunlight, which is why all the leaves on a tree aren’t pointed directly at the sun.

If man wants to wants capture significant solar energy he should try to mimic how trees and all plants capture sunlight. Solar Botanic Energy Systems wants to try to do this: Build artificial trees the generate power from sunlight, and going a step further, generate power from the wind too.

In its concept Solar Botanic will use a combination of technologies on artificial trees to generate power. Using nanotechnologies, leaves would become solar generators using light and heat to generate power. Where the leaf connects to stem on a branch (in a real tree the petiole) nanopiezovoltaic material would be incorporated. The rustling of the leaf in the wind or rain would cause this small generator to generate even more power.

The company plans to design 20 different “species” of artificial trees. Its first project is a Solar Botanic palm tree to be planted at an undisclosed location in the Middle East. This palm tree with its 36 power generating fronds will generate more than 5000 kilowatt hours per year of electricity, according to the company.

Natural trees work as wind breaks, shade buildings to keep them cool, are attractive and add value to properties. Can an artificial, power generating tree do all that and provide clean power too? This concept, as with all unusual and offbeat clean energy providing ideas, should be considered as the energy and climate change crisis continues.

Links:

e-mail Solar Botanic: solarbotanic@apollo.lv

--- Sun Drenched Parking Lots: A National Energy Asset.