WEST BETHESDA, Md. –
The old adage that collaboration breeds innovation holds true time and time again at Naval Surface Warfare Center, Carderock Division in West Bethesda, Maryland.
As leaders in innovation for the U.S. Navy, Carderock often brings together its workforce of scientists and engineers and partners with other government agencies, private companies and universities under Cooperative Research and Development Agreements (CRADAs).
Through a CRADA, both parties involved contribute and share ideas to make a bigger and better product which is mutually beneficial to the industry. According to Carderock's Director of Technology Transfer Dr. Joseph Teter, Carderock has the most cumulative CRADAs from fiscal year 1989 to fiscal year 2016 than any of the Naval Surface Warfare Center activities.
In a CRADA effort started July 2006, Carderock teamed with Oceana Energy Company to develop and test an in-stream hydrokinetic device to be used in coastal communities to harvest ocean currents, tides, or river flows. Their effort led them to concentrate on this technology's usefulness in remote communities in Alaska. According to a report released by Oceana, the remote nature of many of the communities in Alaska make energy a critical challenge with costs that can be 5-10 percent higher than grid-connected locations. According to the Environmental Protection Agency, diesel fuel and heating costs in remote Alaskan villages such as Nenana and Kivalina can cost as much as $10 per gallon. With many of these communities close to a river, Oceana recognized the potential for river-based, hydrokinetic power generation to provide a renewable source of power.
"This project is a true testament to the benefit of CRADAs for domestic industrial development," Teter said. "With this product especially, it also shows that it honestly takes approximately 10 years to get a technology from concept to the marketplace. If you're writing Google apps, obviously it's only months, but to get a real-world physical device constructed and to market -- especially in the difficult environment of putting something at sea -- that's a serious effort."
Carderock played an integral role in the testing and design of the device. The first phase of the Oceana device evaluation was testing the turbine in Carderock's David Taylor Model Basin tow tank. The basin is among the largest of its kind in the world, containing a shallow-water basin, a deep-water basin, and a high-speed basin. Using its sophisticated combination of towing carriages, wave-makers and measuring equipment, engineers are able to determine the sea-keeping qualities and propulsion characteristics of ship and craft models up to 40 feet in length.
According to the Oceana report, the basin provided the perfect location for initial testing because the objective was to obtain performance data in a clean environment free of sediment and other contaminants before proceeding to river conditions in Alaska.
Steve Ebner, division head of Carderock's Marine and Aviation Division, led a small team of Carderock engineers and worked in collaboration with Oceana and Carderock's Propulsors Branch to design and test the device. Matthew Madalis, a mechanical engineer in Carderock's Maritime System Hydromechanics Branch, coordinated testing in the basin.
"The rim itself is actually moving around so there's a series of magnets in the rim that's moving and coils in the stationary section, and that's what creates the electrical power," Ebner said while discussing the design. "It is simple magnetics -- simple electrical generations technologies."
The Oceana device includes fins both radially outward and radially inward of the rotating duct. The goal was to build the next-generation hydrokinetic device which included an integral electrical generator, magnetic axial bearings and hydrofoils specifically designed for river environments. According to Ebner, by including blades on both the inside and outside, the reaction loads on the ring tend to be balanced and generate more power. The device can then leverage the force exerted on it by the natural water flow in a river, thus allowing the turbine to generate energy.
During the three days of testing in the model basin, the device was able to generate up to 8.15 kilowatts of power. The device's rotational rate was calculated by placing a single black fin on the device which could be tracked while viewing video playback.
In the Oceana report, the company considers Carderock to be an integral part of their team and future success. It notes the testing facilities are unparalleled and the staff was professional and knowledgeable. Overall, the tow tank testing provided critical data to determining the performance of the device and giving engineers an idea of the device's behavior in river conditions before proceeding to the actual river testing. By thoroughly testing the device in Carderock's basin, engineers ultimately determined the turbine's potential to provide an alternative energy source for Alaskan communities.
"Working with CRADAs, the engineers in my division like to collaborate for two very important reasons: first, the goals are always different which gives them an opportunity to think outside of the box; and secondly, the technology we learn from doing this kind of work is always fresh and it aids in their professional development," Ebner said. "It is especially beneficial when these opportunities to work with leaders in the industry lead to the use of the technology in some programs that are going on right now within the Navy."
Madalis said CRADAS are also beneficial to engineers because they allow the engineer to optimize resources and work together with another party to come up with solutions and conduct expanded research.
"In terms of the benefits for Carderock, this Oceana device was on the front page of the business section for the Washington Post about a year ago; it was right when they started testing up in Alaska," Madalis said. "It's refreshing to get recognized for your work as an engineer because a lot of what we do -- especially with some of the technologies that are exclusively designed for the Navy -- isn't available for public release. CRADAs allow for more open research."
An analysis released by Oceana Energy stated the size and location of Alaska makes it the leading potential of hydrokinetic energy in the U.S. It is estimated Alaska has approximately 40 percent of the total river energy, 90 percent of the total tidal energy and approximately 60 percent of the total wave energy in the U.S. With this new technology, the state's geographic location and abundance of flowing water, Alaska has the potential for being the hub for hydrokinetic power generation. Through the humble start of a CRADA between Carderock and Oceana Energy, this potential is on its way to realization.