outside of Boulder City, Nev. The panel’s probably a decade old, she says, and has been kept
around the lab for internal testing.
Once Gray levels the scanner, target and
laser, and calibrates the camera, her test is ready
to move forward. Although the measurement
process can take 1.5 hours, the hard part is
already over. “The setup is where all your errors
come in,” she said. Scanning is mostly automat-
ed, and with the clicks of a few buttons, Gray can
amass the images and data — accurate to within
0.2 milliradians — she needs. “I usually have
along my other laptop,” she said, “so that I can
multitask, check for email and fill the time.”
Besides testing for internal record keeping,
NREL’s CSP lab also collaborates with indus-
try manufacturers, conducting third-party veri-
fication testing for companies such as SkyFuel.
There’s much back-and-forth, as products are
commonly tested at different stages in the devel-
opment process and then tweaked accordingly.
It’s not uncommon for the same model of mir-
ror to be pumped through NREL testing several
times — in the development/prototyping, mass
production and deployment phases.
For Gray, the most exciting phase of test-
ing is deployment. Several times a year, Gray
and associate Ben Ihas are assigned to the field,
bringing them to operating CSP facilities in
California, Nevada and Florida. Because they
have to ensure the camera always captures the
laser, and there’s no light switch, the team works
by night. “We can be out until 2 or 3 a.m.,”
Gray said. “Everybody’s grouchy. And we have
to have equipment that’s redundantly rugged.
We’ve learned that when you’re tired you’re
more likely to drop things.” In the desert and
marshland night, critters and crawlers can keep
the NREL engineers on their toes. Gray gets
excited when recounting a trip to the 75-MW
parabolic trough plant in Martin County, Fla.
“It’s really cool,” she said. “The first time I was
there, there was a 6- or 7-foot alligator walking
around the field — it was amazing. [There are]
wild hogs at night. And they say snakes too, but
I didn’t see any.”
Back in the lab, Gray values her job for the
access to national laboratory resources and the
flexibility she’s granted not being tied to a spe-
cific company. “I could run tests and collect data
from here to next Tuesday, but it’s what you do
with the data that really makes it or breaks it,”
she said. “[At NREL], I get to set up my own
tests, analyze the results and make changes as I
see fit and how I think it will help industry.
Denn
advance my skill set,” she adds. “Now, I can
write my own programs to do ray-tracing mod-
els that simulate VSHOT.”
When she started at NREL, Gray had just
wrapped up her master’s in mechanical engi-
neering at the University of Nevada, Las Vegas
(UNLV). As early as her sophomore year as an
undergraduate, also at UNLV, she had worked
in CSP, doing performance testing and mainte-
nance in a student job for Amonix. In retrospect,
her career inclinations were prescient: In the
coming years, mechanical and optical engineers
with CSP experience will become hot commodi-
ties. According to GTM Research, there are 17
gigawatts (G W) of in-the-pipeline CSP projects
expected to come online around the world in
the upcoming years. That’s a ramp up of 1,700
percent — today there is only about 1 GW of
CSP in operation.
Another upshot of working at NREL is that
it’s put Gray in a good place to connect into the
solar community. On the recommendation of
her then-future supervisor, Chuck Kutscher, she
successfully ran for a board of director’s seat at
the American Solar Energy Society (ASES) in
2007. Gray’s made a positive contribution to the
nonprofit organization, based just up the road in
Boulder, Colo., ever since.
