Because it smells bad
Ummm . . . windmills use the wind to keep them turning. No biofuels are involved.
Use as gas
source:(http://en.wikipedia.org/wiki/Biofuel)we use biofuels because they do not make as much pollution as normal fuels.
Biofuels
Challenges to widespread use of wind energy include intermittency of wind supply, land-use requirements for wind farms, potential negative impacts on wildlife, and high initial investment costs. Additionally, issues related to transmission and grid integration can also restrict widespread adoption of wind energy.
If they are diesel powered they can.
There is widespread use of the internet.
Perhaps greed. Because leds cost less and last longer. Or mabye there not bright enough or to bright.
In order to grow the crops required to produce biofuels more forests need to be knocked down to make the necessary fields.
SG Biofuels was created in 2007.
The steady increase in carbon dioxide concentrations in the atmosphere come from our use of fossil fuels. If we were able to stop using fossil fuels, the amount of carbon dioxide in the atmosphere would stop rising. Biofuels are a partial answer, because by using biofuels you are reducing our use of fossil fuels.