Storing wind power
Wind's 30 MW Kahuku wind power project in Hawaii is helping the island
state move to renewable energy—and features a 15 MW system
said to be the largest energy storage system integrated with a wind
farm in North America.
Perhaps more than any other U.S. state, Hawaii can benefit in a very
significant way from developing sources of alternative energy. The
island state has no traditional energy sources (oil or natural gas) of
its own and is dependent on burning imported oil to generate electrical
situation is starting to change, and the state government, utilities,
and renewable energy companies are looking to move Hawaii along the
alternative energy curve.
of the latest projects helping that shift to renewable energy
Wind's 30 MW Kahuku wind power project on the North Shore of the island
of Oahu, which was connected to the grid earlier this year.
when doing the planning and development work for the Kahuku project,
First Wind benefited from a less than successful previous wind power
project in the area dating back more than 20 years. The Hawaiian
Electric Company tried out three different types of wind turbines in
the Kahuku area in the 1980s and 1990s. They ran into problems with
corrosion from the high salt content in the air, and the turbines were
not very efficient.
the wind power industry is very different in 2011 and so is its
equipment, and the Kahuku area possesses a wind resource that is just
area is one of the best wind sites on the island of Oahu," notes Wren
Wescoatt, development manager for First Wind in Hawaii. "We first
started looking at it in 2006 and then purchased 500 acres there in
2007, in an area that is very close to the site of the previous wind
big benefit to First Wind from the previous project is that residents
were familiar with having wind turbines in the area and were generally
supportive of wind power. "That was a big plus for us," says Wescoatt.
this kind of situation, the normal education/information process,
usually required when building a new wind farm, probably would not have
we did it anyway," says Wescoatt. "The community said they already knew
about wind power. But we went through a lot of the same steps. The
knowledge level was already high.
area residents who had been around for a while were already familiar
with wind turbines; consequently, they had a lot of good questions.
Instead of asking basic questions like what color the turbines were
going to be, they were asking how many megawatts they would be and what
we were going to do to prevent corrosion and make sure the turbines
was a more sophisticated conversation with the community."
Hawaii, in general, the wind profile is not only reasonably strong, it
is also very steady, says Wescoatt. "We have tradewinds that blow night
and day, most of the time, from the same direction. And Kahuku is about
a mile from the ocean, so we get the breeze coming in right off the
site itself is in the foothills of Oahu and is located near some shrimp
and prawn farms, very close to the Turtle Bay Resort. That said, the
area is generally agricultural—the wind power project was
built on land formerly used to grow sugar cane.
are some unique challenges to building a wind farm in Hawaii. If you
are building a wind farm in a large wind power state, such as Texas,
land is generally fairly available. But land is scarce in Hawaii. Its
modest 10,931 square miles could easily fit into a corner of Texas,
with its 268,580 square miles. So there is the resulting pressure to
make the best use of land in Hawaii. And the land carries a fairly
hefty price tag.
one of the challenges we face," says Wescoatt. "The alternate uses of
the land we are using have fairly high expectations in terms of
financial returns. Land is very valuable here, and when it is
developed, it is often developed for residential uses or for a resort,
with a very high price tag.
can be difficult to find land in Hawaii that may be suitable for wind
development, and sometimes the cost is prohibitive because there are
many other competing uses for the land."
are the facts of life in Hawaii, but First Wind is familiar with them
through the development of its first wind farm in Hawaii, the 30 MW
Kaheawa wind farm on the island of Maui, which was completed in 2006.
were benefits to First Wind being an established wind power player in
Hawaii, having a successful track record with the Kaheawa wind farm.
Kaheawa, we were known for having a thorough community outreach effort,
and making sure we listened to the communities that would be hosting
these wind projects.
had established a good track record, and the government agencies knew
that we would be upholding the commitments we made to the community, so
that definitely worked in our favor. They know that First Wind will
walk the talk and honor our promises."
Kaheawa project, says Wescoatt, has exceeded all
expectations—it is producing nine percent of the Island of
Maui's power throughout the year, and it is a very steady performer.
were looking to repeat that success with the Kahuku project.
In terms of logistics, Wescoatt reports that they had good access to
the Kahuku site; a main highway was about half a mile away and building
the access roads they needed was not a problem. In fact, access was
excellent, says Wescoatt, but it was not due to the previous wind farm
facilities. The U.S. Army does training in the area, and there is also
a heavy equipment training center next door, so there were already good
roads into the area.
Wind selected Clipper Windpower's2.5 MW Liberty wind turbines for the
Kahuku project on the North Shore of theisland of Oahu.
Topographically, the site consists of rolling hills, with elevations
from 100 to 300 feet.
Equipment and material were brought in through one of Oahu's harbors
and then trucked out to the site. "That was a bit challenging, with
some of the winding roads we had to traverse to get to the site."
Due to its sensitive eco-system, Hawaii requires a much more demanding
environmental approach than most states on the mainland. As with the
Kaheawa project, First Wind developed a Habitat Conservation Plan for
"In general, Hawaii has a very high incidence of species extinction, so
the state has very strict environmental regulations and a very high
level of concern for federally listed species," says Wescoatt.
"Consequently, we approach the environmental requirements very
"With our wind farms, we want to make sure we are doing the best we can
with existing information to study species and develop a plan to create
a kind of net benefit. We can't completely prevent a take incident, but
we want to make sure that over the life of the project, we are creating
a benefit to the species over and above any potential take that might
If there is a species that may be impacted, First Wind looks at how it
can contribute to research and preservation programs. This includes
work with the state on research programs for the endangered Hawaiian
bat, and programs that incubate and raise chicks of endangered bird
species. They also look to identify and protect colonies of endangered
species off site, through predator trapping or fencing of sensitive
"Hawaii is a beautiful place, but it's very small and its resources are
unique and very fragile. We want to make sure we take care of what's
here and, as a company, that we don't negatively impact those
Once the project was approved, construction swung into high gear. They
had some high wind days during construction, which caused some erection
work to be slightly delayed, but construction proceeded well, and they
finished the project ahead of schedule.
"There weren't any hiccups in terms of construction efforts, but it was
still an extremely complicated project," says Wescoatt. "A big part of
that was the battery storage system."
The project includes a 15 MW system said to be the largest energy
storage system integrated with a wind farm in North America. The
battery energy storage system assists in smoothing fluctuations in wind
Xtreme Power is the developer and manufacturer of the Dynamic Power
Resource (DPR) large-scale energy storage and power system used on
Kahuku. The project marks Xtreme Power's largest commercial DPR
currently in operation.