All of the electricity generation discussed so far has involved turbines. Either water is heated (by burning fuel or from nuclear fission) to make steam, that turns turbines, or wind, water or waves turn the turbines directly. Solar power works on a completely different principle. In the photovoltaic effect, absorbance of light energy causes some substances to emit electrons. In a solar cell, this movement of electricity is captured as an electric current. Unfortunately, while this has great potential as a renewable resource, it is still not used very much. A couple of years ago solar accounted for 1% of US electricity and estimates suggest this will rise to 4% by 2020. Many LEGO creations, particularly futuristic ones, feature solar panels, such as Annie Corder's city,
Doctor Sinister's Aurora Station,
and Zg1134's WALL-E.
Here's a solar power installation from Legoland Billund.
LEGO has even made two official real solar cell elements that are used in a few of the educational Dacta sets.
Here Peter Hoh used one of them to make a solar-powered car.
And that's it for our little foray into understanding how electricity is produced. I'll go back tomorrow to a series of more random MOCs that have popped up recently.