with Duke on North Carolina solar project
utilized a single-axis tracking technology platform on their largest
solar farm in the U.S.—a 17.2 MW solar plant with Duke Energy
in Davidson County, N.C.,—which is said to be the second
largest active solar photovoltaic deployment on the east coast.
It was not that long ago that building a 17.2 MW solar plant would have
been a considerable challenge. But after talking to Jason Stevens,
vice-president of global project operations for Sun Edison, it seems
like the new Davidson County solar plant in North Carolina went up like
any other. It was just larger—considerably larger.
in conjunction with partner Duke Energy Carolinas, the solar farm
covers 200 acres and is comprised of more than 63,000 photovoltaic
solar panels. It is expected to generate an estimated 28 million
kilowatt-hours annually—enough energy to power 2,600 homes a
not a unique design," says Stevens. "We utilized a single-axis tracking
technology platform with polycrystalline module technology, so the
modules track the sun across the sky."
also utilized Advanced Energy bi-polar inverters. "We chose the
bi-polar inverter platform because it is more efficient than a
traditional single polar inverter platform," says Stevens.
is SunEdison's experience in installing numerous solar farms globally,
including a 70-megawatt facility in Italy last year, that allows them
to assess what works best and when.
assessment includes not only the features of the technology, but also
quality and pricing as well," says Stevens. "So while this was a good
solution for this system, we continue to look at other applications
a ground-mount solar project, Stevens says there are typically three
choices. First, you can have a fixed tilt system where you install a
rack structure that maintains the same orientation of tilt year-round.
Second, you can have a single access tracker installation that tracks
the sun from east to west. Lastly, you can choose a dual access power
station, where the modules can move both east and west, as well as up
fixed tilt system will have a lower energy output because it isn't
optimizing tracking of the sun. While it may be a bit lower cost, we
see the cost of a single access tracker and the increased output from
the tracking of the sun to exceed the benefit of a lower cost fixed
tilt at a lower energy output."
SunEdison/Duke project was completed in phases, which might seem more
expensive—that a company couldn't take advantage of economies
of scale. But Stevens says although there are probably some incremental
costs with respect to efficiencies, operational execution, and project
management overhead, in this case, those costs weren't excessive
relative to the overall labor and materials costs of the
the SunEdison/Duke project, there were two phases based on the timing
of the build—a 4 MW first phase followed by a 13 MW second
matter how many phases a project may entail, the entire project design
is typically completed at one time. "We do that because we'll have an
idea of the overall project size and the scope of the project. Based on
either construction schedules or customer requirements or project
financing and timing, we may then build in phases," says Stevens.
For a project the size of this one, SunEdison ideally likes to have it
installed in around six months. The Duke project was done in phases
because of certain material logistics constraints, and the first phase
took approximately five months to install.
Davidson County solar farm covers 200 acres and is made up of more than
63,000 photovoltaic solar panels. It is expected to generate an
estimated 28 million kilowatt-hours annually—enough energy to
power 2,600 homes a year.
"We were doing a lot of the development work," explains Stevens. "When
we started doing the remaining 13 megawatts, that actually was
completed in probably about a six-month timeframe as well. But once
again some of that pertained to material supply
constraints—module supply was a bit more constrained at that
In the end, the first 4 megawatts were launched in December of 2009.
The remaining generation capacity was launched in December 2010.
In this case, as with many projects, SunEdison partnered with Duke to
build the project but owns and operates the power station. "For most of
the systems that SunEdison develops and delivers under our financing
structures, we also perform operations and maintenance responsibilities
as well," says Stevens.
He adds, "We do scheduled and unscheduled maintenance calls on
projects, because we have the expertise and the resources in place to
do this better than our customers. It aligns with our model of selling
energy. Therefore we manage that asset to make sure it delivers the
energy as expected."
When SunEdison began working with Duke, the scope of the project
included not only designing, building, and operating the system, it
also required identifying a site.
"We worked with Duke Energy to identify sites that were close to their
distribution sub-stations," says Stevens. "Once we located the
preferred areas, we chose the site to develop and constructed the
This turned out to be a win/win for SunEdison and North Carolina.
"Solar energy continues to increase in importance to North Carolina
customers," says Brett Carter, president, Duke Energy North Carolina.
"Partnerships, like the one with SunEdison, have allowed Duke Energy to
comply with North Carolina's solar requirements in a cost effective
During development, SunEdison worked well with local parties and Duke
Energy. The only big challenge to the project (in addition to its size)
was building it in phases. "Some of that was being driven around
incentive structures and capacity. Typically, we need to find project
investors that can take advantage of available incentives and, in some
cases, that may span a couple of years," says Stevens.
"As with any new market like North Carolina, it takes some time to work
with and identify parties that are able to take advantage of the
incentive structure and how that set of structures is established," he
The Duke project is a substantial addition to SunEdison's portfolio. It
is the company's largest operating system in North America and the
second largest active solar photovoltaic deployment on the east coast.
"I think it was a great example of us working with a progressive
utility like Duke Energy to develop a project and get it operating,"
Also, he feels that the learning curve when installing the initial 4 MW
helped create a more efficient overall process not only for this
project but others under development globally.
"We had the same construction manager on site for both phases of the
project," explains Stevens. "So while we used two different contracting
parties for the two different phases, the SunEdison project team was
able to learn a lot of lessons, collect a lot of operational
observations, and incorporate those on the second phase."
The efficiencies are evidenced in the construction
schedule—five months to install 4 MW and five to six months
to complete the remaining 13 MW.
Although this may be SunEdison's largest North American project
to-date, don't expect it to remain so for long. They have hundreds of
megawatts scheduled, and the company is involved in projects going up
all over the globe.
"We're trying to take experiences like the Duke Energy project that we
had great success with in North America and expand that and use the
same lessons learned in our global operations," says Stevens.
For instance, SunEdison has an operating team in Europe, a team in
India that is delivering projects in India and Thailand, and new
markets are emerging in China and
Back in the U.S., SunEdison is working on various projects in the
southwest. "We've got a portfolio with a utility in New Mexico, five
projects, each of them just under 11 megawatts," says Stevens. "We'll
also be installing just under 25 megawatts with a utility in Arizona."
With all those installations on the horizon, it's no wonder Stevens
believes solar has a bright future. "I think there's going to be
continued development in the large ground-mount applications over the
next several years. Utilities are starting to become more familiar and
understand the benefits of solar PV—and because of that,
we've seen a huge explosion in interest from the utility section in
large scale projects."
"As the cost curves of solar continue to drop, there will be a point
where the cost of solar energy will be more cost effective, and
significantly more rooftop installations will be done. At that point, I
think there's going to be a very large explosion in residential and
commercial installations. I can see the point coming—four or
five years out—when folks will just opt to install a system
on their rooftop regardless of incentive structures that might be
He also believes it will take a great deal of work to get there. "The
continued development and alignment between utilities and solar PV
integration companies will need to be part of a bigger strategy. We
will get to a point where we'll see a significant increase in the
potential market for solar, and it will need to be aligned with the
interconnection and grid management strategy that we have with the
utilities and as a nation.
"It's a dynamic industry," he added. "You get a lot of personal
satisfaction in seeing the positive changes and knowing that your
company had a hand in doing it."