Even for those who are not science orientated, the discussion of renewable and sustainable energy sources is universal- a theme that has a lot of pertinence to this day and age. First to make the definition clear, there is a slight difference between the terms, renewable and sustainable energy sources, which are often used interchangeably.
The term renewable Energy refers to an energy source that cannot be depleted or completely exhausted, whereas the term sustainable is very similar to renewable but it simply refers to the different economic and social issues to using renewable sources.
There are many different types of renewable resources that could potentially be harnessed at a magnitude that could eradicate all the world’s energy problems. One of theses sources which is on the rise, is the use of Solar energy or Photovoltaics. One impressive figure: if we covered an area the size of Nevada with solar panels, there would be enough energy harnessed to power the entire United States. Although this seems almost too good to be true, this goal has many obstacles. Many are against solar plants (this is also true for wind turbines) because of their perhaps less than natural appearance. Many governmental regulations as well as communal hesitation and the expense, slow the development of solar energy “farms.”
A few electric facts about solar energy:
Solar energy generated constant electricity or direct current. Most household appliances run on AC, alternating current, which means that the photovoltaics need a inverter to change the photovoltaics into alternating current.
-The term “light intensity” (what we measured for the experiment) is simply the measure of the energy of light. The higher the intensity logically means the more photons are generated equalling a greater current and voltage.
*The speed of light is measured at c=3 x 10 to the 8th power m/s.
A solar panel is made from silicon. Silicon is a semi-conducter, meaning it is partly an insulator of electricity as well as partly a conductor.
Experiment:
With solar energy in mind and these facts in mind, we conducted an experiment of our own to really grasp the amount of energy a single solar panel could produce.
We were given our own small, “handheld” solar panel , roughly the size of the palm of a hand and a flashlight. Using our lego robots, connected to the program, Labview. Our task was to measure the amount of energy produced at different distances from the flashlight to the solar panel.
With the flashlight off, the amount, the amount of voltage measured was : .017384 watts
0 distance: .42662 watts
(solar panel held:) 2 inches away: .39587
3 inches away: .324022
5 inches away: .30990
7 inches away: .229394
As indicated by the numbers, the farther the solar panel was away from the flashlight, the less energy was produced.
Here’s a graph: Lab
The seoond part of the experiment was to see how the energy changed when putting different color filters over the flashlight and see how that affected the amount of energy.
The first filter we tried was
Light Blue: with a voltage (at zero distance) was .396
meaning that the light blue did not really adversely affect the amount of light produced. The voltage was similar to when the solar panel was held 2 inches away from the flashlight.
Pink: voltage measured was .324, similar to when the panel was held 3 inches away from the flashlight.
and finally
Dark Blue: voltage measured was .310, similar to when the was held 5 inches away from the flashlight.
Conclusion: This experiment really demonstrated how much energy can be captured, even in the form of a handheld device. Even though solar cells max out at around 23% efficiency, it is still a form of energy that with modern day technology becoming easier to produce, and produces no greenhouse gases; way better for the environment!