Tour: Solar Panels at UVA

Hi, I am Sathish Anabathula. I'm with Power & Light within Facilites at
UVA. The Power & Light group is primarily responsible
for power distribution, exterior lighting, and rooftop solar. We at UVA have three different types of solar. One, the main, is the UVA-owned rooftop solar. Second is the PPA, Power Purchase Agreement. We agree to buy all of the power at two of
the offsite sources of Facilities.

Each is about 120 acres. And then the third is the solar lease, which
we are on, the roof of Ridley Hall, used to be Ruffner Hall, we agreed to lease this roof
to Dominion Energy for 15 years. All of the electricity that is produced on
this site goes back to Dominion, but we get payment for leasing the roof. The four buildings that we have that are owned
and operated by UVA are Skipwith Hall, Alderman Substation, Clemons Library and Ivy Stacks. All these combine for about 327 kW. And then the solar lease facility, the
bookstore facility is about 179 kW and then Ridley Hall is about 275 kW. All of these systems have something in common,
that is the module. The solar module is either a combination of
60 or 72 cells, and each cell is made up of three different materials, and primarily they're
all silicon-based.

So, a p-type and an n-type silicon materials. N-type has an extra electron, and then a p-type
has a hole to accept the electron. When sunlight excites the n-type material,
the electron jumps from that material over to the p-type material, having a transfer
of electron, movement of electron. Movement of electrons is electricity. So that generated electricity and when you
put together 60 or 72 cells, you get the voltage, a usable voltage, that you need. And that is DC, direct current, and we take
that to AC through the inverter, and then from there we bump up the voltage to put it
on the grid. And William is going to go over, you know,
the system more in detail. Hi, my name's William Evans and I'm with UVA
Facilities Management Power & Light, and we're on the roof of Ridley Hall.

You can see we have over 960 solar panels
up here, and each panel is made up of 60 cells, and each cell has about one volt of voltage
under full sun. And so you can think of like a 9-volt battery,
if you put together nine cells you have about that much voltage. And so each panel has 60 cells, so you put
those together and you wind up with about 40 volts. Then you put each panel end to end with the
next panel, and by the time you get 10 or 15 together you get up to about 600 volts. This is all DC power, so it's direct current,
like a battery, which is not what we use in our homes. We use alternating current. So we have to take the DC current to an inverter,
and then that inverter converts it to alternating current, which we can use in our homes. Here at Ridley Hall, this is owned by Dominion
Energy, the power company, and so it actually goes down to a transformer on the ground level,
which we'll see later, and then up onto the power lines and then around to Charlottesville.

The way these modules make power is: You have
packets of energy coming from the sun called photons. When the photon enters the solar module,
it enters the silicon crystalline structure, and energizes an electron enough so that it
breaks free. Sathish was talking about the p-type and n-type
material in the module, which actually creates a standing electric field. When the electron is knocked loose in the
standing electric field, it moves from negative to positive, and like Sathish said, moving
electrons is what we call electricity. And that's how we do it. We have a website for tracking all our renewable
energy projects at UVA. On this website you can also find additional
resources such as classes that are being offered at UVA, and the research that is going on
at UVA in the field of solar energy. Additionally, we have also made the Sustainability
Plan available to the public on this website, and all the actions UVA is taking to reduce
greenhouse gas emissions and its carbon footprint. As always, you can reach out to me or William
if you have any additional questions.

Thank you..

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