Re: Can trees be used to generate electricity?

Hi Stuart!
The answer is, "not yet."

Since trees are driven by sunlight, what you really might be after is a biological solar-cell. Such things do exist, but are experimental only as far as I know. They don't use trees directly, but instead use the photosynthesis process as part of a solar battery. Here's one link about a lab which is investigating bacteria photosynthesis for solar energy production http://www.nanothinc.com/NanoVentures/Publications/Scotland/issue4/issue4.html

Another possibility is to somehow use trees to provide fuel for a fuel cell. A fuel cell is much like a standard battery, it is a chemically-powered "electricity pump". But rather than storing its fuel as metals which corrode, it uses hydrocarbon fuels which oxidize. Fuel cells can use fuels from biological sources: methane from fermentation, or alcohol. There is nothing you could use today as a tree-battery, but future biological batteries might resemble modern fuel cells: http://whyfiles.news.wisc.edu/shorties/fuel_cell.html

Genetic manipulation and nano-engineering might someday give trees which supply energy to us in a directly-usable form. But by that time, it would probably be just as easy to breed phosphorescing walkway-light shrubs as the appropriate product.

Of course we use trees for energy production right now. Chop them down and burn them (or use coal, the remains of ancient forests). Or grind trees up and ferment them into methanol. I imagine that neither the trees nor your customers approve of such things!

On another topic: trees have been used to directly generate electric energy from wind power. A set of trees was tethered by cables, and as they swayed in the wind, the powerful but slow-moving cables were geared upwards and used to spin a generator. This experiment was done in the last ten years, but I've found no references about it.