A dearth of public information, complicated marine environments, and even the corrosive effects of bubbles are some challenges facing companies that seek to produce energy from river currents, tides, and waves, so Sandia is helping companies on the frontier of the coming marine hydrokinetics (MHK) industry navigate these and other concerns.
Harnessing the energy of a wave can do many things: propel a surfer toward shore or serve as a source of virtually limitless energy for 21st century America. (Photo by Randy Montoya)
Through DOE support for Sandia’s MHK research, the Labs plans to release its first report this fall analyzing the computer-simulated performance of a tidal turbine, a river turbine, and a wave-point absorber, which bobs on the surface to capture energy from waves, says engineer Rich Jepsen (6122). Eventually, Sandia will analyze up to 10 devices.
MHK is the study of harnessing the kinetic energy that results from the motion of water.
“The current MHK industry looks a lot like wind did 30 years ago,” says Daniel Laird, manager of Water Power Technologies Dept. 6122. “We want to take what we’ve learned to compress the MHK development from the 30 years it took wind energy down to 10 years.”
Sandia’s analysis aims to accelerate the MHK industry in the US by showing companies and DOE where investments can be made to bring down the costs of using America’s waterways and the oceans to produce energy — whether from an engineering, environmental permitting, or administrative standpoint. Companies will be able to use these reference models to make their own decisions about which design or system components are worth their investment, Rich says.
“As a nation, we don’t have a handle on what the performance is and the actual cost of the energy that is generated,” Rich says.
Sandia also is getting real-world experience through its partnership with New York City-based Verdant Power, which is at the forefront of the MHK industry.
Verdant has operated the world’s first grid-connected array of multiple tidal turbines in the East River and will operate the first tidal power plant in the country, says Dean Corren, the company’s director of marine current technology.
After Sandia began working with Verdant in 2008, DOE awarded an Advanced Water Power Project grant that expanded the partnership to include the National Renewable Energy Laboratory in Golden, Colo.
Verdant’s turbines are mounted on towers on the river bottom, turning with the changing currents to always point downstream so they catch the currents and produce energy as they rotate.
“The goal of the project was for Sandia to design a stronger, more efficient blade made of composite materials, similar to what’s used in wind,” says Sandia engineer Josh Paquette (6121).
Sandia surveyed and studied prospective blade foil shapes, performed essential, computational fluid-dynamics analyses of the rotor, and then of the turbine as a whole, Corren says.
The result is a blade that is stronger and thicker, more resistant to corrosion and cavitation, and one that can be mass-manufactured, Josh and Corren say. Cavitation is the creation of tiny water vapor bubbles at low pressure that can collapse and damage the surface of the blade.
“When these bubbles collapse, they put out a lot of energy and it can be very erosive, so it can literally chew up an underwater propeller,” Josh says. “We tackled this issue using the same methods we used in wind, where we did computational fluid-dynamics analysis of the blade.”
This Fifth Generation Free Flow System is being built by Verdant and will be tested this fall. Should all go as planned, Corren says, Verdant plans in 2012 to begin installing, in phases, 30 turbines in the East River, which at peak production could supply enough energy for the equivalent of about 700 homes.
Operate for three years unattended
Earlier generations of turbines were tested for two months; this commercial-type turbine is designed to operate for three years unattended, Corren says.
Sandia also is learning from Verdant’s experience in the water by studying the debris, mud, and biological contaminants that grow on the underwater turbines, Josh says.
Other companies and government agencies have had a difficult time obtaining research and performance data because nearly all of it is proprietary.
When Sandia started its research, DOE noticed this and asked Sandia to create reference models that established benchmarks companies could use to test their own custom models to determine whether they should enter the market, Rich says.
Sandia is analyzing basic designs, environmental factors, and costs, Rich says.
Sandia hydrologist Jesse Roberts (6122) says an array optimization tool developed by Sandia specifically for MHK devices analyzes both the effects of the environment on the devices and, conversely, the devices’ effects on the environment.
“You can use this tool to place turbines in whatever fashion you think is appropriate throughout your water column to see how they interact with each other,” he says. “It will tell you how much energy you converted with that layout and how the water flow changes throughout the system, near and far field.”
While the water flow is faster near the surface, potentially creating more energy, turbines sometimes can’t be placed too close or they would interfere with shipping, recreation, or wildlife, such as birds that dive deeply for their food, Jesse says.
Tide power is ‘weather-proof’
Sandia provides information about how underwater turbines and wave devices change the physical
environment to aquatic ecologists at partner labs, who study the effects on marine life. Jesse says that while each aquatic environment is different, the more questions that can be answered up front, the better companies can predict environmental permitting costs or research requirements.
Early estimates show that a significant amount of the current US national electricity demand may eventually be met through tidal and wave energy generation, and, moreover, these power sources will be located near population centers on the East and West coasts where demand for energy is high.
Tidal power in estuaries and straits is predictable and steady, as opposed to wind and solar power, Corren says. “We look up at the moon and can know what’s going on, and we don’t have worry about the weather,” he says.
Rich also is looking at another potential resource for the MHK industry at Sandia, a 50-foot-deep pool with a nearby large electrical power source that could be converted into a large-scale facility to generate waves under controlled conditions needed for accurate large-scale testing of devices.
With some additional investment, “our lake is big enough that companies could put in a prototype and do full-system tests all the way to generating electricity,” Rich says.
There are signs that Sandia’s efforts to help the MHK industry are paying off. Rich says a growing number of companies are becoming interested in Sandia’s work on the array optimization tool and materials and coating research for the turbine blades.
“Being in this industry at the early stage, being able to define the future of an entire industry is interesting. It’s like being a researcher in wind energy 20 to 30 years ago,” Jesse says. “Hopefully, we’ll be able to follow this for quite some time and help influence the direction it goes.” - Heather Clark
A drive across the nation’s landscapes is revealing more wind farms cropping up on the horizons. As of last year, 37 states are home to at least one wind farm, and the more than 40 gigawatts of installed capacity accounted for about 3 percent of the electricity generation in the US.
A 2008 DOE report, however, points to much greater potential and suggests that by 2030, 20 percent of the nation’s energy needs could be supplied by wind turbines. While the idea of harnessing the wind’s energy is ancient, the global scale of the industry only began to be realized in the last five years. With this realization, the growing need for highly reliable wind turbines becomes paramount, but little data exists to point out opportunities and areas for improvement.
“Wind energy is leading our nation’s and the world’s clean energy movement. As we become more dependent on these energy sources, we must make sure that we are installing the most effective, viable, and reliable systems possible to transform the energy picture of the future,” says Jose Zayas, (6120) senior manager for Renewable Energy Technologies.
To address this need for data, Sandia is completing the development stage to create a Continuous Reliability Enhancement database for Wind (CREW). This database will be the foundation for analyses to identify primary failures and associated improvement opportunities, enable reduced operating and maintenance costs, and provide industry benchmarks. The DOE-sponsored project focuses on the nation’s utility-scale turbines of one megawatt and higher.
Data in 36 key operating parameters
“This project is the first effort to compile a comprehensive dataset that reflects the performance of the US wind fleet. With better understanding of current performance of the major turbine systems, wind operators can direct their efforts toward improvements in those areas that will drive increased reliability and efficiency,” says team lead Bridget McKenney (6121).
By tapping into turbines’ existing supervisory control and data acquisition (SCADA) industrial control systems, Sandia researchers are collecting information on 36 key operating parameters such as wind speed, blade angles, component temperatures, and torques. Every two seconds, a wind turbine’s SCADA system captures a picture of how the turbine and its components are performing relative to a defined operating envelope and its environment. Currently, four wind plant owner/operators are participating in the development phase of the CREW project by providing this SCADA data to Sandia’s CREW database via automated data collection software developed by Strategic Power Systems (SPS). SPS is a key partner with many years of experience in collecting high-volume data from steam and gas turbines via a proprietary software tool. SPS has converted this tool to collect data from wind turbines.
“Our assignment from DOE is to characterize the national fleet. We’re not looking at one technology, one location, or one company,” says Alistair Ogilvie, CREW database lead (6121). “We want to look at the entire US fleet and create baseline statistics for the industry to be able to say, ‘This is what you and your competitors should be trying to achieve.’”
To reach a statistically representative baseline, CREW will aggregate data received from all participating wind plants. The current data set represents approximately 2 percent of the nation’s wind turbines, but as the project grows, CREW researchers expect to include approximately 20 percent of turbines to establish representative benchmarks.
The volume of data to sift through is mind-bending. The print collections of the Library of Congress are roughly 10 terabytes; CREW’s data set, with dozens of variables taken at two-second intervals from a fifth of the nation’s wind turbines, is expected to dwarf that. Over the past six months, four pilot plants with a combined 345 turbines, or about 2 percent of the nation’s installed turbines, have generated two terabytes of raw data. This data has been provided to the CREW database by the SPS collection tool. To process this enormous dataset into a usable database that can readily support a wide variety of queries, CREW turned to Sandia’s Enterprise Database Administration team (9538).
Identifying likely failure points
“The goal is not to have the biggest database — the goal is to transform it into a useful dataset for the analyst,” says Michael Mink (9538). “We’re taking the raw data on weather, wind speed, angles of the blades, and so on, at two-second intervals, taking time chunks of that, summarizing it and putting it into another database that people can query easily and quickly.”
Determining which components are most likely to fail is an important part of benchmarking. Major turbine systems include a set of three blades, rotor, shaft, generator and gearbox, any of which have the potential to fail. Turbines that are down for maintenance or repair are expensive — in addition to lost productivity, the cost of hiring a crane for repairs can be upwards of $250,000, and because there are only a few cranes in the nation large enough to handle turbine heights and component weights, an operator might wait for months before the turbine is up and running again.
The CREW team will use the dataset to identify the top turbine systems and components responsible for the majority of downtime, which will then inform specific research and technology improvements. “If we can identify those components most at risk, we can provide the industry and DOE with information on which ones need further research and where funding should go,” says Alistair. Components that were once considered the most vulnerable become more reliable, allowing the industry to move on to addressing the next challenge.
“We’re excited about the results so far, and look forward to the next few years, as we make an important contribution to our industry to improve the reliability through a component-level focus,” Bridget says. “It’s an important project for the industry and the nation as a whole, and we could not have been successful without the outstanding partnership of Corporate Computing and SPS, and the support and leadership from DOE. Together, we can share our expertise to help shape the future of the nation’s wind energy generation.”
Dealing with 10,000 truckloads of data
The Continuous Reliability Enhancement for Wind (CREW) program is wrapping up its pilot phase, and has already generated 68 billion rows of data. Over its lifetime, the project is expected to produce more than 10 terabytes of data, roughly the equivalent of 10,000 pickup trucks filled with books. Such a fantastic amount of information would be nearly impossible to wade through, but the CREW team turned to Sandia’s Enterprise Database Administration team (9538) to turn it into something usable. The team has taken the 68 billion rows of data and transformed it into a structured database format to help CREW better use the information they’ve collected.
“Earlier this year, we formed a five-person Process Innovation Team focused on supporting customers working with a terabyte of data or more,” says Cynthia Huber (9538), manager of Enterprise Database Administration (EDA). “We have built new and innovative processes, designed to handle big data loads and transformations, on top of our already tried-and-true database support standards. CREW’s requirements for consuming big data fit well with our goal of enabling Sandia’s missions in managing large volumes of data, so we are enthusiastically supporting that effort.”
The techniques used by EDA are expected to translate to multiple other industries, such as solar, that have the potential to generate large quantities of data, but also need that data to be user-friendly. With the mission of providing valuable database administration services to Sandia’s applications development community that ensure the integrity, availability, recoverability, accessibility, integration, and security of Sandia’s corporate data, the EDA is continually working to meet Sandia’s database needs. Working with terabyte-scale projects is an evolving field, but the EDA is well-equipped to handle such challenges.
“We have a highly skilled group of database administrators with many years of multiplatform database management experience servicing both enterprise and mission level applications,” Cynthia says. “Additionally, our ability to scale up to handle these data volumes is made possible by the excellent support we receive from our enterprise IT partner Infrastructure Computing Services (9324), which provides the system and storage administration for the database servers that ultimately host this capability. They provide us the hardware footprint that enables the database administrator to perform the data integration and transformation necessary to deliver valuable and secure data to our customers. We’re experts in data integration, data transformations and securing data for customer use.” -- Stephanie Hobby
Nine Sandians witnessed history from Mission Control at Johnson Space Center as Atlantis made its final flight, marking the end of NASAís 30-year space shuttle program. For the past 22 missions ó every one since NASAís 2005 return to space ó a team of Sandians has worked tirelessly to protect the astronauts by inspecting the orbiterís thermal protection system for damage.
NASA turned to Sandia for assistance in 2003 after Columbia’s debris-damaged heat shield failed, which caused the tragic accident that took the lives of all seven on board. In response, a Sandia team developed the laser dynamic range imager, or LDRI, which generates 3-D images from two-dimensional video. The LDRI Orbiter Inspection System (LOIS) is attached to the orbiter’s boom, and scans the heat shield twice — once 18 hours after liftoff and then again the day before re-entry — to ensure that no part of the orbiter’s heat shield was damaged during launch or orbit. Without that sensor system, and its ability to detect minute anomalies, the shuttle might have remained Earthbound.
“It’s been an excellent relationship between Sandia and NASA, and a true team effort,” says Bob Habbit, (5711) manager of Sandia’s Remote Sensing and Communications System group. “These people that we work with here are in effect co-workers. We’ve had a very tight relationship, so it’s tough to see that relationship come to a close for this project, but again, we are very proud of what we’ve been able to do and the support we’ve provided for NASA.”
The effort needed to execute the scan is extensive. In the early days, Sandia took a 24-person team to oversee all aspects of LOIS; some of that work was eventually turned over to NASA and its contractors, so for the last 17 missions, usually only nine or 10 Sandians went to Houston for the hands-on work.
“We led the inspection activity and operations in the payloads operations center for the data collections. We validated that the data was correct and that the sensor was operating properly, and then we reviewed the work of the NASA team to make sure that the data had been processed correctly,” Bob says. “That was our principal role, but in the event that there was some defect found, we provided technical expertise and support to the mission management team.”
Sandia’s role extended beyond the launch and re-entry; team members worked intensely before, during, and after each mission to ensure everything went smoothly.
“After every touchdown, once the orbiter returned to Kennedy, we did a full checkout and calibration on LOIS, and then we would integrate it back to the orbiter at the Orbiter Processing Facility,” Bob says. “Before the next launch, our team would again test the system on the launch pad before the payload bay doors were closed.” Those efforts sometimes came at great personal sacrifice to Sandia’s team, as many had to work through holidays and family occasions like birthdays and anniversaries. “We’re all very happy to do it because of the importance of our work to the mission.”
A desire to continue NASA partnership
The shuttle program launched 359 astronauts into space since its inception in 1981, was responsible for transporting and maintaining the Hubble Telescope (which captured its millionth observation on July 4), and was the workhorse that assembled the International Space Station. As the nation waits to find out what the next manned mission in space entails, Sandia’s team is already participating in panels and committees to explore NASA’s future needs.
“There is certainly a desire to continue that partnership; we feel like we’ve provided great value to NASA and the shuttle program. Without our sensor and our ability to provide the confidence needed for a truly high-quality inspection, the whole complexion of the shuttle program would have been very different,” Bob says.
NASA gave Sandia a tremendous honor after exceptional work during STS-131 in April 2010. NASA managers invited Sandia’s team to be part of the STS-131 plaque-hanging ceremony, a long-standing tradition to acknowledge outstanding efforts during the mission. The ceremony took place in the Mission Evaluation Room’s conference room, which is across the hall from the historic Apollo Mission Control Center.
Sandia’s multidisciplinary effort for the LOIS program has spanned the Labs and has included people from divisions 2000, 5000, and 9000. Without such a collaborative effort, Bob says, the LOIS effort would not have been possible.
Sandia’s final inspection of Atlantis was July 19, and while everything checked out and all went smoothly, there was a hint of sadness among the team that day.
Bob wrote in an email to his colleagues: “This milestone is met with conflicting emotions — a great deal of pride and accomplishment for an excellent contribution to the nation and sadness to see Sandia’s NASA shuttle program partnership come to closure.” -- Stephanie Hobby