Drawing From the Sun: UVA Expands Its Solar Array

“The Data Science project is very small, as the roof space conducive to solar is small,”  Sathish Anabathula, associate director of power and light for UVA Energy and Utilities, said. 

The University has contracted with Tiger Solar to install a 208.12-kilowatt system on the Old Ivy Road structure, which will provide approximately 27% of the building’s electric draw. The roof-mounted panels feed directly into the building, using an inverter to translate direct current into a usable alternating current. Each solar panel has 72 cells converting solar energy to electricity. The solar-generated current, and the current generated by Dominion Energy, feed the building’s electric needs.

“Think of it as a bucket of water filling from two taps, the bigger tap from the utility and the smaller tap from the building’s solar array, and you are drawing water from the bucket,” Anabathula said. “The way most of our buildings work, much of the load is in the heating and cooling of the building as well as the computers and servers, so the buildings never go to zero electric draw.”

Sathish Anabathula, associate director of power and light for UVA Energy and Utilities, said the electricity generated by the solar panels will power the building at 2420 Old Ivy Rd. (Photo by Erin Edgerton, University Communications)

The buildings have meters that constantly monitor how much electricity is coming in from the utility and the solar array, as well as how much is being used in the building. When the solar array provides enough to satisfy the building’s demands, the meter turns off the feed from the utility; any excess electricity it generates is sent onto the electric grid and the meter runs backward.

“If we don’t use it, we’re sending it back to the grid,” Anabathula said. “But it is very few times where we’re spinning the utility meter backward. Our electric bill is based on a month duration, so if the meter is spinning forward five days out of the week and spinning back just a little bit a couple of days in a month span, we’re still consuming. Technically, we’re not selling anything back to the grid, just reducing the bill.”

And the reduction is less per unit than what the University is paying.

“If we buy electricity at 10 cents per unit, about 4 or 5 cents of that is the production cost,” Anabathula said. “The other 5 or 6 cents is the distribution, maintenance and all the costs that are associated with it. When you over-produce and you’re selling units back to the power company, they are not going to pay you 10 cents, which they charge you for the usage, they are going to pay you at 4 or 5 cents.” 

Anabathula said the Old Ivy Road installations should break even in nine years, without factoring in an increase in electric rates, which would accelerate the payback. Recent changes in the law have made it more lucrative for the University to purchase solar panels now. Homeowners have been able to get a tax rebate on their solar panel purchases, but not the University.

“As a state entity, UVA doesn’t pay taxes,” Anabathula said. “We were not able to get the rebate that was available to the homeowners and the private companies. But with the federal Inflation Reduction Act, that rebate is available to even businesses like us that do not pay taxes.”

The base rebate is 30%, but if the University purchases U.S.-made solar panels, the rebate is increased to 40%. The University is getting its panels from Mission Solar Energy in San Antonio. 

Anabathula said the panels may last 40 to 50 years, though they lose efficiency as they age. 

“Let’s say these modules are about 20% efficient, meaning they can convert about 20% of solar energy into electricity,” Anabathula said. “In year 25, they’re going to be at 17% or 16%, based on what the manufacturer warrants. So, in year 25 they still producing, but not as good as on Day 1.”

While reducing electricity costs, solar panels have other benefits, especially when considered in light of UVA’s commitment to two solar farms operated by Dominion Energy specifically for UVA. 

“Installing solar panels on roofs is one of the strategies of our sustainability plan,” Anabathula said. “A large-scale solar farm has huge economies of scale and faster payback compared to rooftop solar. The two solar farms UVA has agreed to buy power from have been operating for a few years now. They help us achieve the sustainability goals we had set.”

The University has invested in two Dominion Power solar farms. The UVA Hollyfield Solar project produces a peak of 17 megawatts of direct current, a figure representing about 12% of the University’s electricity demand. Dominion’s Puller Solar facility, a 120-acre solar farm in Middlesex County, is producing a peak of 15 megawatts of electricity, about 9% of the University’s electricity demand.