A. 0% - 15%
B. 15% - 30%
C. 30% - 45%
D. Over 45%
Before I give you the answer, take a look at the picture below. Unless you have flown over Peddie recently, you might not be aware that solar panels are installed in all of the locations highlighted in green. The capacity of the Peddie solar array is almost 1 megawatt.
While the size of our installation is impressive and a "megawatt" certainly sounds like a lot, the most important statistic is of course the answer to my question above. How much of the electricity that is used by the Athletic Center is being produced by our solar panels? If you would like to know the answer to this question you don't have to take my word for it, you can see for yourself anytime! We now have a real-time web accessible display of how much electricity we are producing. Currently this can be seen on the display in the Technology Center, but you can also view it from any Flash enabled web browser by going to the Peddie solar statistics web page. A sample of the solar stats page is shown below.
[Note: if you have any trouble viewing the stats page using Chrome just manually refresh the page and it will display properly.]
One thing that it is important to keep in mind when you view the page is the difference between power and energy. Power is a measure of the rate at which energy is being consumed or produced at a given instant in time. On the Peddie solar statistics page, power is expressed in kilowatts (kW) with 1 kilowatt equivalent to the amount of power used by ten 100-watt light bulbs. On the other hand, energy is a measure of the quantity of power consumed. On the solar stats page, energy is expressed in kilowatt hours (kWh).
One helpful way to conceptualize the relationship between power and energy is to think of water in a garden hose. You can think of power as being a measure of the strength of the stream of water coming out of the hose at any instant in time. Using this analogy, energy would then be the volume of water that came out of the hose over a period of time.
The solar stats page shows a graph of the power currently being delivered by the solar panels and by the electric utility company as well as a comparison of today's energy delivered by solar vs. utility. The bottom of the page shows the energy statistics for solar vs. utility for today, this week, this month, and even this year. When you look at the figures for this year keep in mind that the solar array did not come fully online until late spring.
Lastly, you will also see the current irradiance displayed on the page. The irradiance is a measure of the amount of power in sunlight measured in watts per square meter. If solar panels could turn all of the sunlight that hits them into power then the amount of power they produced would be their area (measured in square meters) times the irradiance. In practice, power is lost in many ways so the efficiency of solar panels is much less than 100% and the efficiency fluctuates based on several factors. It is interesting to see how things such as the time of day, time of year, and cloud cover affects the irradiance.
