Compared to wind and solar energy, wave energy has remained relatively expensive and hard to capture, but engineers from Sandia National Laboratories are working to change that by drawing inspiration from other industries.
Sandia’s engineering team has designed, modeled and tested a control system that doubles the amount of power a wave energy converter can absorb from ocean waves, making electricity produced from wave energy less expensive. The team applied classical control theory and robotics and aerospace engineering design principles to improve the converter’s efficiency.
During a multiyear project funded by the Department of Energy’s Water Power Technologies Office, engineers from Sandia’s Water Power program are using a combination of modeling and experimental testing to refine how a wave energy converter moves and responds in the ocean to capture wave energy while also considering how to improve the resiliency of the device in a harsh ocean environment.
“We are working to create methodologies and technologies that private companies can harness to create wave energy devices that will enable them to sell power to the U.S. grid at a competitive price,” Sandia engineer Ryan Coe said. “By getting more energy out of the same device, we can reduce the cost of energy from that device.”
Advanced control of wave energy converters yields increased energy absorption
Sandia’s wave energy converter is a large 1-ton ocean buoy with motors, sensors and an onboard computer built at a scaled down size for a testing environment. Commercial wave energy converters can be large and are generally part of a group of devices, like a wind farm with multiple turbines.
“These devices can be in open ocean and deep water, maybe 50 to 100 miles off the coast,” Coe said. “An array of wave energy converters, maybe 100 devices, connected to an underwater transmission line would send the wave energy back to shore for consumption on the grid.”
To capture energy from the ocean’s waves, a wave energy converter moves and bobs in the water, absorbing power from waves when they generate forces on the buoy. Sandia’s previous testing focused on studying and modeling how the devices moved in an ocean-like environment to create a numerical model of their device.
Using the model they developed and validated last fall, the team wrote and applied multiple control algorithms to see if the converter could capture more energy.
“A control algorithm is a set of rules you write that prompts an action or multiple actions based on incoming measurements,” Sandia engineer Giorgio Bacelli said. “The sensors on the device measure position, velocity and pressure on the hull of buoy and then generate a force or torque in the motor. This action modifies the dynamic response of the buoy so that it resonates at the frequency of the incoming waves, which maximizes the amount of power that can be absorbed.”
The control system uses a feedback loop to respond to the behavior of the device by taking measurements 1,000 times per second to continuously refine the movement of the buoy in response to the variety of waves. The team developed multiple control algorithms for the buoy to follow and then tested which control system would get the best results.
“Controls is a pretty big field,” Sandia engineer Dave Patterson said. “You can operate anything from planes to cars to walking robots. Different controls will work better for different machines, so a large part of this project is figuring out which control algorithm works and how to design your system to best take advantage of those controls.”
Bacelli said that while the primary objective of the control algorithm is to maximize energy transfer between the wave and the buoy, the amount of stress being applied to the device also must be considered.
“Resonance also stresses the entire structure of the device, and to expand the longevity of the device, we need to balance the amount of stress it undergoes,” Bacelli said. “Designing and using a control system helps find the best trade-off between the loads and stress applied to the buoy while maximizing the power absorbed, and we’ve seen that our systems can do that.”
Theory becomes reality in the Navy’s world-class wave tank
Results from numerical modeling with the control algorithms showed a large potential, so the team took the converter to the U.S. Navy’s Maneuvering and Sea Keeping facility at the Carderock Division in Bethesda, Maryland, in August to test the new control methods in an ocean-like environment. The wave tank facility is 360 feet long and 240 feet wide and has a wave maker that can generate precisely measured waves to simulate various ocean environments for hours at a time. Sandia used the wave tank to simulate a full-size ocean environment off the coast of Oregon, but scaled down to 1/20th the size of typical ocean waves to match their device.
“The accuracy of the wave they can generate and the repeatability is outstanding,” Bacelli said. “The ability to recreate the same condition each time allowed us to conduct very meaningful experiments.”
The team ran a baseline test to see how the converter performed with a simple control system directing its movements and actions. Then they ran a series of tests to study how the various control algorithms they had designed affected the ability of the device to absorb energy.
“This year, the device can move forward, backward, up and down, and roll in order to resonate at the frequency of the incoming waves,” Bacelli said. “All degrees of freedom were actuated, meaning there are motors in the device for each direction it can move. During testing we were able to absorb energy in each of these modes, and we were able to simulate the operating conditions of a device at sea much more accurately.” In fact, the tests showed theory did match reality in the wave tank. The control algorithms were able to more than double the amount of energy the wave energy converters were able to absorb without a control system.
The team is analyzing the testing data and considering further options to refine the control systems to maximize energy transfer.
Learn more: Robotics principles help Sandia wave energy converters better absorb power of ocean waves
The Latest on: Wave energy
[google_news title=”” keyword=”wave energy ” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]- Wuthering Waves Starter Guide: System, Elemental Combo Effects, Echoes - Technobubble Gamingon May 20, 2024 at 6:00 am
Liberation? Concerto? Ensemble? What’s all that mean? Here’s a Wuthering Waves primer, including elemental effects, mechanics and lore for beginners.
- D-Wave CEO Urges Leaders to Embrace an AI and Quantum Future Now in New Forbes Technology Council Columnon May 20, 2024 at 4:00 am
Wave Quantum Inc. (NYSE: QBTS) ("D-Wave" or the "Company"), a leader in quantum computing systems, software, and services, and the world’s first commercial supplier of quantum computers, today ...
- Sword Of Voyager (Sword) Overview – Wuthering Waveson May 19, 2024 at 8:32 pm
Sword of Voyager is a 3-star Sword in Wuthering Waves. Read ahead to gain insight into its overall performance.
- Is This the Most Realistic Wave Pool Yet? (Video)on May 19, 2024 at 6:00 am
The thing about real-world replications – from CGI on the silver screen, to virtual reality headsets, to I can’t believe it’s not butter! – is that, they take something that already exists, and tweak ...
- With its energy network nearly destroyed, Ukraine already fears the winteron May 18, 2024 at 11:42 am
While the rolling plains of Ukraine’s countryside are in full spring bloom, officials already fear what the distant winter will bring as a major energy crisis grips the country and power companies ...
- Texas power prices briefly soar 1,600% as a spring heat wave is expected to drive record demand for energyon May 18, 2024 at 10:49 am
The state's grid operator, the Electric Reliability Council of Texas (ERCOT), predicted demand would jump from 57,486 megawatts on Friday to 71,893 MW on Monday, 72,725 MW on Tuesday, and 74,346 MW on ...
- New 360° Wave Tech Aims to Be the Safest In the Wave Pool Gameon May 17, 2024 at 4:37 pm
But from a business standpoint, developers are likely looking for something that matches wave quality with factors like operating cost, energy use, safety, and of course, how many people ($) can enjoy ...
- Chicago Mayor Courts Québec Investors to Fuel City's Sustainable Economic Waveon May 17, 2024 at 1:50 pm
Mayor Johnson of Chicago met with Québec leaders to discuss sustainable investment opportunities, focusing on green and blue economies.
- The Next Wave: 10 Innovative Water Technologies That Will Change the Worldon May 17, 2024 at 11:02 am
Water is an essential resource for life, yet access to clean, safe water remains a challenge for many around the globe. As climate change intensifies and populations grow, the need for innovative ...
- Daily on Energy: Trump threatens $1T in clean energy funding, 5M solar installations, and more solar tariffson May 16, 2024 at 1:50 pm
Another Trump administration would put $1 trillion in clean energy funding at risk, according to a new report from data analytics firm Wood Mackenzie. The report outlines how a Trump presidency could ...
via Google News and Bing News