Bacon's Rebellion

Testing the Impact of Solar

Solar panels at Dominion’s Philip Morris USA partnership program site.

Virginia has been slow to embrace small-scale solar energy, but Dominion’s Solar Partnership Program could show how to integrate variable solar generation into local distribution systems.

by James A. Bacon

The biggest solar farm built in Virginia to date isn’t very big by anybody’s standards — only 2.5 megawatts, enough to power about 500 homes. But Dominion Virginia Power, which owns and operates the facility on land leased from Philip Morris USA, says it will apply what it learns from the project to smooth the integration of larger volumes of solar power into Virginia’s electric grid in the future.

Built for $4.9 million, the Philip Morris facility is one of ten projects either completed or underway under Dominion’s “Solar Partnership Program.” The scale is tiny: Projects conducted in cooperation with various Virginia universities and corporations total 6.7 megawatts, about one two-hundredth the capacity of the new gas-fired power station the utility is building in Greensville County.

The purpose of the program is experimental. Dominion’s system, like those of most electric utilities, is dominated by huge power plants that rely upon high-voltage transmission lines to move electric power long distances and lower-voltage lines to complete the connection to local homes and businesses. Anticipating a surge of solar power, much of it small-scale and scattered, Dominion wants to see how solar impacts the reliability of its distribution system.

“What happens when you put a new power source on a lightly loaded circuit?” says Brett Crable, director-new technology and energy conservation: “Do our traditional power grid components handle it well?”

Dominion has come under intense criticism from environmentalists who say the power company is biased toward building massive, gas-fired power stations instead of more distributed, smaller-scale solar power. Dominion has dragged its feet on solar, argues Ivy Main, author of the Sierra Club-Virginia’s Power to the People blog.

The Commonwealth had only about 22 megawatts of solar installed as of the end of 2015, but by the end of this year, we should be comfortably into the triple digits. That’s still trivial compared to neighboring North Carolina, which added over 1,000 megawatts last year alone, but it’s grounds for celebration here in the “dark state.”

Dominion counters that it is moving slowly but deliberately in order to preserve the integrity and the grid and the reliability of service. Solar is an intermittent power source — it generates power only when the sun shines. Its output can fluctuate dramatically over the course of a day as clouds sail by. While the high-capacity transmission grid is robust — PJM Interconnection maintains that its service territory, which includes Virginia, could accommodate up to 30% renewable energy sources — Crable says less is known about the impact of variability on local distribution systems. “We want to do it the most effective way possible by learning on a small scale.”

After a few months of operation at the Philip Morris location, Dominion has already made one finding: Electric power is flowing the opposite direction the circuit is designed for. That’s not necessarily a bad thing, says Crable, but only time will tell.

The Philip Morris project is one of ten small solar facilities either completed or underway in partnership with Virginia corporations and educational institutions. Participants include Canon Virginia, Old Dominion University, Capital One, Virginia Union University, Prologis, Randolph-Macon College, Western Branch High School, Merck and the University of Virginia.

Dominion approached Philip Morris, which operates a major tobacco de-stemming operation in eastern Chesterfield County. The cigarette manufacturer provided 11 acres of vacant land in a 20-year lease. Aside from wanting to be a good partner with Dominion, which has always been responsive to power outages and other issues, Philip Morris thought the solar farm would complement its reclaimed wetlands and cogeneration facility, says Greg Ray, senior vice president of manufacturing. The company saw “an opportunity to educate people about ways to make manufacturing more sustainable.”

While Dominion leases the land, it owns and operates the solar farm itself. Power from the Philip Morris facility will feed into a “lightly loaded” circuit in a rural corner of Chesterfield County, which has different conductive characteristics than more heavily loaded circuits. Dominion also is interested in how roof-mounted and ground-based solar might have different effects.

Why can’t Dominion learn from other electric utilities that have pursued solar power more aggressively? “We’re very attuned to what other utilities are doing but not all electric systems are built the same,” says Crable. Distribution lines vary in voltage, and Dominion may use different arrays of equipment to regulate the voltage. Dominion, he says, wants first-hand information about how solar works on its system.

Main with the Sierra Club is not impressed by how the program has progressed. The General Assembly passed a law in 2011 that allowed Dominion to build up to 30 megawatts of solar energy on leased property. As she wrote on Power to the People:

The program was supposed to proceed in two phases, with 10 MW in place by the end of 2013, and another 20 MW by December 31, 2015. However, the program got off to a very slow start. In August of 2014 the company acknowledged it was behind schedule and would likely not achieve more than 13 or 14 MW of the 30 MW authorized before it ran out of money. On May 7, 2015 Dominion filed a notice with the SCC that it needed to extend the phase 2 end date to December 31, 2016, and confirmed that it would install less than 20 MW altogether.

Dominion has evaluated hundreds of sites and engaged in advanced negotiations with dozens of customers, says Nathan Frost, manager of New Technology and Renewable Programs. The need to select distribution circuits with unique operating characteristics limited the number of suitable locations. Further narrowing the potential sites was the need to reach long-term agreements with willing customers.

“The ten sites that are now complete or under construction represent a significant investment in renewable energy by Dominion,” says Frost, “and will allow the company to better understand how to integrate solar in a safe and sustainable manner.”

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