Our independent variable was the weather condition and the dependant variable was the electrical output of the solar panel. Our hypothesis was that the electrical output would decrease as the cloud cover increased. During sunny conditions there was not a cloud in the sky. During partly cloudy conditions, there were some clouds in the sky with sunny breaks. During overcast conditions, the sky was entirely covered with cloud. Precipitation is defined as a steady down pouring of rain or snow during the test period.
Our hypothesis was accepted. During sunny conditions, we experienced our highest energy output, which averaged 20.74 volts. During partly cloudy conditions, we experienced our second highest electrical output of 18.21 volts. During overcast conditions our average electrical output was 14.88 volts. Finally, during precipitation, we experienced our lowest electrical output, with an average output of 12.66 volts. The precipitation condition was used as our control. We compared all of our other conditions' output to the electrical output recorded during precipitation. Using the ANOVA method of statistical calculation, we determined that our results were not due to chance. In fact, the probability of our results being due to chance is .0002% (see appendix)
We found that as the light intensity increased, our efficiency decreased. This was an incidental finding that we observed while examining our data. This indicates that the weather condition is not the only factor which affects the energy output of the solar panel. According to Dr. Ashok Vijh, Ph.D., D/Sc., O.C., C.Q., F.R.S.C. of the Institut de Recherche d'Hydro Quebec, it is well understood by engineers who specialize in the field of solar energy that the efficiency of solar panels' voltage output decreases with increasing amounts of light energy. There is a mathematical formula which explains this phenomenon. Simply stated, the voltage loss due to resistance in the solar panel increases with increasing light intensity. Therefore, the solar panel cannot produce voltage energy which is directly proportional to the light intensity.
Further investigation may be undertaken to determine whether solar panels may have better performance in higher latitudes. Other future experiments could include: analysis of electrical output during different temperatures, calculation of the longevity of solar panels and comparison of the amount of time that different solar panels take to fully charge a batttery.
Solar panels and solar electricity could be used for much more than powering small batteries. Solar electricity could be used to power heating systems, air conditioners lighting, stoves, ovens, and other systems which consume electricity. In fact, remote areas that are inaccessible to electric grids can use solar panels to meet their electric demands. As we discussed earlier, remote areas of Tibet currently use solar panels in place of kerosene and cow dung. Solar panels could be placed on the roofs of houses in isolated areas in order to bring the modern conveniences which urban dwellers take for granted. As well, solar power stations could reduce the reliance on coal burning and nuclear energy. Our coal and oil supplies are finite and when burned, emit the carbon dioxide and other by products which contribute to air pollution and global warming. Nuclear energy produces highly radioactive and unstable waste for which governments around the world are working tirelessly to find safe storage. In addition, there is the risk of disasters due to nuclear reactor failure such as the accidents that occurred at Chernobyl, Ukraine and Three Mile Island, Pennsylvania.
Solar energy is very cost efficient. In Freiberg, Germany, architect Rolf Disch has built an apartment complex that is run entirely on solar energy. The solar panels which power this apartment complex are so efficient that the German power company pays each resident an average of seven hundred and seventy-five Canadian dollars a month to buy the surplus which that they produce. This is an example of how financially efficient solar energy can be. If solar power stations are built, money can be saved due to the reduction of demand for fuels such as coal, uranium, oil and gas, as well as the transportation and storage costs of spent nuclear fuel rods. Finally, solar powered cars could reduce our dependence on Middle Eastern oil. Oil is a finite resource and its price is volatile due to instability in the Middle East.
While we conducted our experiment, we faced many challenges. Firstly, we had to stand out in the cold for an extended period of time, while sometimes facing heavy snow. Also, the solar panel became covered in snow during a snow storm and had to be constantly brushed clean. Finally, the project would not have been possible without a solar panel. It was also difficult to find the kind of solar panel we required. This demonstrates one of the challenges that solar energy proponents face: the fact that solar panels are not widely available. Since need drives the market, panels are still relatively expensive as they are produced in small numbers.
Now that we have experience with solar panels, we would make several key changes to our science fair project. We would design an experiment in which we would charge a battery with the power generated by a solar panel in different weather conditions. Using this battery, we would try to power a small appliance such as a radio or an electrical toothbrush to demonstrate a practical application for the energy produced by a solar panel under different weather conditions.