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.”
TAU researchers discover algae can yield mass quantities of hydrogen, the world’s cleanest energy source
Researchers at Tel Aviv University have revealed how microalgae produce hydrogen, a clean fuel of the future, and suggest a possible mechanism to jumpstart mass production of this environmentally-friendly energy source. Their results have been published in back-to-back studies in Plant Physiology and Biotechnology for Biofuels.
The research was led by Dr. Iftach Yacoby, head of TAU’s renewable energy laboratory, and Rinat Semyatich, Haviva Eisenberg, Iddo Weiner and Oded Liran, his students at the School of Plant Sciences and Food Security at TAU’s Faculty of Life Sciences.
Researchers in the past believed that algae only produce hydrogen in the course of a single microburst at dawn lasting just a few minutes. But Dr. Yacoby and his team used highly sensitive technology to discover that algae produce hydrogen from photosynthesis all day long. Armed with this discovery, the team harnessed genetic engineering to increase algae’s production of this clean energy source 400 percent.
Increasing algae’s output of hydrogen
Laboratory tests revealed that algae create hydrogen with the assistance of the enzyme hydrogenase, which breaks down when oxygen is present. The researchers discovered effective mechanisms to remove oxygen so hydrogenase can keep producing hydrogen.
“The discovery of the mechanisms makes it clear that algae have a huge underutilized potential for the production of hydrogen fuel,” said Dr. Yacoby. “The next question is how to beef up production for industrial purposes — to get the algae to overproduce the enzyme.”
Some 99% of the hydrogen produced in the US comes from natural gas. But the methods used to draw hydrogen from natural gas are toxic — and wasteful.
Answering the need for clean energy
“I grew up on a farm, dreaming of hydrogen,” said Dr. Yacoby. “Since the beginning of time, we have been using agriculture to make our own food. But when it comes to energy, we are still hunter-gatherers. Cultivating energy from agriculture is really the next revolution. There may be other ways to produce hydrogen, but this is the greenest and the only agricultural one.
“The world burns in just one year energy it took the earth over a million years to produce,” Dr. Yacoby continued. “We must stop being hunters and gatherers of energy. We must start producing clean energy — for our children and for our children’s children.”
Dr. Yacoby is now researching synthetic enzymes capable of increasing hydrogen production from microalgae to industrial levels.