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NREL Helps the Navy with Renewable Energy Site Assessment at Indian Ocean Base

December 20, 2013

Reaching Diego Garcia, a remote island in the middle of the Indian Ocean, is not easy, but recently NREL’s Otto VanGeet and Owen Roberts embarked on the long journey there. As part of an integrated Navy and NREL team, their goal was to help the Navy reduce costs by integrating wind and solar power with fossil fuel generators.

NREL staff, along with members of the Naval Facilities Engineering Command, conducted a net-zero renewable energy site assessment in November at the atoll which stretches about 40 miles in a thin U-shape. The island's renewable energy potential—along with the possibilities for energy systems integration—really excited the team.

"Because of its locale, the base is all diesel-powered," VanGeet said. "They spend a lot on electrical generation,” referring to the multiple megawatts of diesel generators that power the airstrip and facilities to support the Navy’s mission. Reducing fuel costs is a high priority for the Department of Defense. In 2009, the Navy set a goal that 50% of their shore-based energy would come from alternative sources, and that 50% of their installations would be net-zero. For more than a year, more than 30 team members from across NREL disciplines have given various levels of technical assistance and conducted site assessments at 22 Navy installations to support the Navy in pursuit of the military's ambitious energy goals.

NREL's Expertise Makes It a Logical Partner for the Navy

NREL's renewable energy and energy efficiency expertise makes it a logical partner in this global enterprise. During six days of work at Diego Garcia, VanGeet and Roberts covered plenty of ground for the assessment.

"We looked for renewable energy and efficiency opportunities," VanGeet said. They analyzed the existing generation system to help determine specifications for new generators that can be integrated with variable power sources. They also discovered that the island is a very strong candidate for renewable energy options.

"We were looking particularly for solar and wind siting opportunities," he said.

To provide more data, they deployed a SODAR wind-measuring device which will monitor conditions for a year. That instrument will likely back their empirical assessment. "Diego Garcia has good solar, and great wind resources," VanGeet said.

However, there are several barriers to attaining a net-zero system at Diego Garcia. "Integrating a high penetration of variable energy onto the diesel grid and keeping the grid stable will be challenging," he said.

Still, VanGeet believes that the proper integration of renewable and diesel generators, energy storage, and other strategies could help the Navy make significant progress toward their energy goals. He says NREL’s applied problem-solving approach practiced in the field directly ties back to much of the work at NREL’s main campus such as the equipment testing at the Energy Systems Integration Facility.

The NREL team will submit a draft report with recommendations to the Navy, and the document will include options for renewable energy resources. “We want to make sure that diesel, photovoltaic (PV), and wind fit together nicely, and have the proper storage and demand control," VanGeet said.

"We've looked at a lot of islands," he said. "This is one of the most promising for PV and wind power hybrid systems that we've seen."

Also, VanGeet said he believes that solutions used on Diego Garcia would be "replicable for other places, and other island nations." As he notes, hundreds of islands and sovereignties face similar energy constraints.

-Written by Ernie Tucker