SunEdison + Duke = Largest Solar PV Farm in U.S.


A deal between solar producer SunEdison and power company Duke Energy could produce the largest solar photovoltaic farm in the United States. Built and operated by SunEdison, the farm will be located in Davidson County, N.C., and, at 21.5 megawatts, is likely to be the largest photovoltaic array in the country at the time it is constructed. (OptiSolar plans a 550 MW PV plant, which it is targeting to start construction on in 2010). Duke Energy says it plans to buy all the electricity output from SunEdison’s plant.

SunEdison’s PV farm will cost an estimated $173 million, the Winston-Salem Journal reports. While its final location has yet to be determined, construction of the farm is to commence in 2009 with a minimum of 16 megawatts delivered by the end of 2010. The financial details of the power purchase agreement were not disclosed.

This partnership is the second large photovoltaic deal from Duke Energy in the last month. Earlier Duke announced plans to invest $100 million in a distributed solar roof program that will fund installation and operation of solar systems on residential and commercial buildings.

All of these solar moves from Duke are in preparation for North Carolina’s renewable portfolio standard, which requires utilities to get 12.5 percent of their energy from renewable sources by 2021. Many states have similar, and often more ambitious, renewable portfolio standards, and many utilities, like PG&E, are finding that the demand for renewable power is far greater than the supply.



i think the estimate quoted (US$173M) is off—-that would put both the capital cost and the LCOE for the project way above what SunEd has already completed much smaller rooftop projects for.

It appears someone leaked some info somewhere and the number was misrepresented along the way—a veritable game of telephone. Perhaps it was referring to both the SunEd project and Duke rooftop initiative combined. If so, that would mean the Davidson project was at about $4.60/ watt (173-100/16) installed capex which is line with other larger US projects and makes sense due to the economies of scale gained……with the the ITC, D/E ration, etc thats a LCOE of just under $0.20 per kWh.


A back-of-the-envelope calculation shows that the installation will cost about $8/Watt ($173M/21.5MW).

Using NREL’s estimator (PVWatts) and assuming $0.10 per AC kWh (probably optimistic for wholesale costs), the annual income would appear to be ~$3.4M/yr. With no interest at all, the payback is ~48 years or approximately twice the reasonable life of PV systems.

If they wanted a 15 year payback, could obtain 6% financing and could tolerate a 70%-of-income debt service limit, the maximum debt that could be satisfied is of order $25M, a far cry from the $173M stated. A 25yr payback at 3% only raises this debt ceiling to ~$40M. Even at 0% interest and 100% income towards debt, only ~$80M can be paid back over the 25yr system life.

So, just what shenanigans make this economically viable? Even the promised county investments seem to barely make a dent.

Am I missing something? Surely subsidies cannot make up the other $100M+…

Jaineel Aga

Hey ,

I need a list of the biggest solar installations in the US in the private sector. Any body has heads up on that information.

I have checked all of SunEdison’s projects
and a couple of wesbites showing the largest single PV installations but I need a more concrete list




It´s awesome to see greater investments on solar energy.


It would be awesome if you guys could add some off-the-cuff financial analysis to figure out how long this payback is — based on current going energy rates. Is this really better financially than building a coal plant?

Believe me, I understand the smaller environmental impact…but does this make sense from a financial perspective? That’s how you’ll convince businesses to do this.


Katie Fehrenbacher

Thanks Tyler, OptiSolar is planning a 550MW solar PV farm, which they are targeting to begin construction in 2010. We updated the story to reflect that.


I think the OptiSolar plant planned in California will be the biggest – 500 MW.

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