Wave energy researchers
dive deep to advance clean energy source
Sandia National Labs
One of the biggest untapped clean energy sources on the
planet — wave energy — could one day power millions of homes across
the U.S. But more than a century after the first tests of the power of ocean
waves, it is still one of the hardest energy sources to capture.
Now, engineers at Sandia National Laboratories are conducting
the largest model-scale wave energy testing of its kind to improve the
performance of wave-energy converters (WECs).
The project is taking place at
the U.S. Navy’s Maneuvering and Sea Keeping facility at the Carderock Division in Bethesda, Maryland,
one of the largest wave tanks in the world at 360 feet long and 240 feet wide
and able to hold 12 million gallons of water.
Sandia project leads Ryan Coe and Giorgio Bacelli spend long
days in the dark wave tank, where minimal lighting reduces the growth of algae
in the water.
They are collecting data from their numerical modeling and
experimental research to benefit wave energy technology with improved
methodologies, strategic control systems design and testing practices for wave
energy converters.
“Our goal is to improve the economic viability of these devices,” said Coe. “In order to do so, we are working out ways to control the WEC’s generator to increase the amount of power it absorbs. At the same time, we are looking at how to reduce the loads and stresses on these devices in harsh conditions to ultimately lengthen a WEC’s lifespan in the water.”
Coe said numerous initial studies estimate that improving
control of the WECs’ generators can dramatically increase energy absorption by
as much as 300 percent. Transitioning these simplified studies to more
realistic large-scale devices is the challenge at hand.
To control the dynamics for better, faster results in the wave
tank, Coe and Bacelli are using modeling and control methods that have been
successful in other industries, such as in the aerospace industry.
“The systems we used have
been around for a while, but strangely enough they had never been applied to
wave energy converters,” Bacelli said. “So far, we know the techniques we are
using are more efficient and cost-effective than existing methods. We are
getting more information in a fraction of the time.”
Now that Sandia has completed the first round of analyses in the
water, Coe said the goal is to process all the collected data to develop a new,
enhanced model that will make sure the next test yields even more valuable
results.
“Make no mistake, these are extremely complex machines,” Bacelli
said. “They have to be fine-tuned continuously because ocean waves are
constantly changing. With this setup at the Navy’s facility, we have a unique
opportunity to study the problems and quantify the effects. We want to help the
industry by offering solutions to the challenges the wave energy world is
facing.”
Sandia’s continuing wave energy project, Advanced WEC Dynamics
and Controls, kicked off in 2013 and is funded by the Office of Energy Efficiency and Renewable Energy.
Innovations from Sandia’s Water Power Technologies Program advance our nation’s energy security by making
renewable energy more economically feasible. Contributions include WEC-Sim, an open
source code for modelling the performance of wave energy converters, extreme-conditions modeling and tidal and turbine modeling. Sandia researchers serve as advisers and judges for the
Department of Energy’s Wave Energy Prize competition.
Sandia National Laboratories is a multimission laboratory
operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin
Corp., for the U.S. Department of Energy’s National Nuclear Security
Administration. With main facilities in Albuquerque, N.M., and Livermore,
Calif., Sandia has major R&D responsibilities in national security, energy
and environmental technologies and economic competitiveness.
