Engineering New Frontiers Summer Camp - the School of ...

Energy in the Wind
by Associate Professor Scott Mattews
On a blustery Friday morning in late October, two minivans left the Pangborn
parking lot, loaded with CUA engineering students. I drove one and the other
was driven Randy Swisher, Ph.D., adjunct professor and retired executive
director of American Wind Energy Association. We were beginning the threehour
drive to Garrett County, Pa., the location of the Casselman Wind Project.
Swisher had arranged a state-of-art tour of a wind power installation, owned
and operated by Iberdrola Renewables, one of the world’s largest wind
power companies.
As the vans left the city, the two groups of students from the Alternative
Energy Program began harassing one another using walkie-talkies. As they
got off the interstate, nearing their destination, I missed a turn. The GPS
quickly recalculated. Another missed turn and route recalculation put the
two minivans on a tiny dirt road. After about a mile and a half on the bumpy,
wooded road, the walkie-talkies crackled, “This can’t be right … I can’t
believe these roads are even on a GPS map!” At that point, the GPS began to
indicate that they were “off road” and gave no indication of where to go. As
the students looked out the window, they realized they were driving through
an open-pit mine, an active open-pit mine. A large crane came into view,
shoveling loads of dirt into a dump truck. Some of the students looked worried.
The gravel road led to a hard surface road. The GPS recalculated its
position, and wind turbines began to appear on the horizon. Driving up the
Casselman River valley, the students could look in any direction and see
the tall, white towers on almost every hilltop and ridgeline. They were in
wind country.
Within a few miles, they spotted the “Iberdrola” sign, turned onto another
gravel road, and headed down toward the only building in sight, the Project
Control Center. When they got out of the minivans the wind was strong. The
sound of the gigantic blades slicing through the air was quiet but distinct.
They were greeted by engineers Chris Long, Brad Burkebile, and project
manager Doug Schafer, who invited the group inside and began talking
about the facility: 23 wind turbines, built by GE, each rated at 1.5 MegaWatts,
eight turbines placed on top of a reclaimed coal mine. The employees gave
details about the technology and the day-to-day operation of the facility. The
students asked many questions, all answered with technical detail.
Chris Long then showed the computer terminal and software used to
control the entire wind farm. He showed pages and pages of data being
acquired from the turbines in real time, as well as graphs of power production,
wind speeds, and turbine “availability” on a daily basis, that gave
monthly and annual averages. He described how the entire “wind park”
could be monitored and operated remotely via the Internet. Doug Schafer
then led the group into the parts warehouse, where he showed replacement
components, tools for repair and maintenance, and the safety gear used for
tower ascent, or as he put it “working up-tower.” He then described employees’
annual training for dealing with up-tower emergencies or the rapid
evacuation of the nacelles. The nacelle, which sits atop the tower, contains
the gear box, low- and high-speed shafts, generator, controller, and brake.
Finally, students were taken in groups of six out to one of the turbines
that had been shut down for the tour. Once the massive blades came to a
complete stop, the group approached the base of the tower. Later one of
the students remarked, “I’ve seen them on TV and seen lots of pictures …
Casselman Wind Project, Garrett County, Pa.
cuaengineer
but I never appreciated how big they really are until I stood at the base and
looked up.”
Brad Burkebile opened the door to the tower and led them inside. At first,
everyone seemed quite disappointed to only be touring the “down-tower”
section of the turbine, but after seeing the ladders rising up into the nacelle,
no one complained. Wind turbines don’t have elevators.
Even though the turbine was shut down, the active yaw system was still
functioning. Every few minutes you could hear the yaw motors engage, and
if you looked straight up, you could see the inside of the nacelle turning,
always pointing into the wind. Burkebile explained the functions of the
massive electrical systems installed at the base of the tower: step-up
transformers, power conditioning circuits, phase matching circuits, and the
connections to the local power grid.
The weather turned cold and the wind was beginning to pick up, so the first
group headed back inside the control center to warm up and let the second
group have a look. At the end of the long trip back, we all agreed, “Pictures
on the Internet are never as good as seeing something with your own eyes.”
Students in control center, monitoring the turbines.
fall2011 | 15