monitoring sensors, ships and aircraft if Naval Research Laboratory
scientists achieve their goals of harnessing solar and sea power to
fuel the military for years to come, a top NRL scientist said.
"A worldwide peak of fuel production is expected in five to 15 years,
and increased demand will likely create large swings in price and
availability," Barry Spargo, head of NRL's chemical dynamics and
diagnostics branch, said in an Oct. 14 interview on Pentagon Web
Radio's audio webcast "Armed with Science: Research and Applications
for the Modern Military."
"The bottom line is that we need to develop alternative power and
energy because conservation and efficiency alone will fall short of
meeting future needs," he explained.
The quest for alternative fuel technologies is a top priority for the
Navy, Spargo said, adding that energy research at NRL is diverse,
allowing them to bring together a wide array of disciplines to address
unique problems confronting alternate energy research.
"We're conducting research in a number of areas that look really
promising; however it's unlikely that a single research area will solve
the energy problems that we are facing," Spargo said. "NRL is currently
investing in synthetic fuel production at sea, enhancing fuel energy
density, exploration of methane hydrates in the ocean, energy
harvesting from the sea, fuel cells and batteries, power electronics
and superconductors, and inertial fusion.
"Each of these research areas has significant challenges," he added,
"but certainly promising potential to help solve some of the Navy and
[Defense Department's] future power and energy needs for force
mobility."
One area of research that NRL is pursuing is the feasibility of
sea-based production of hydrocarbon fuels. According to Spargo, the
goal is to produce fuel in the same location where it is being
consumed, specifically to support surface ships and aircraft operations
from carriers at sea.
"This would give battle groups independence from fleet oilers which
provide refueling needs," Spargo explained. It also would cushion naval
forces from future fuel shortfalls, he added, providing energy
independence to the Navy.
Fuel synthesis would be accomplished by a catalytic conversion of
hydrogen produced directly from sea water by the electrolysis of water
and carbon dioxide. "It's a complex process, but we believe that
emerging scientific technology supports the development of synthetic
logistic fuels," he noted.
"There are significant research and technological challenges, but the
potential payoff is really high," he added.
Spargo noted that producing energy from sea water would be carbon
dioxide neutral, thus not adding to the world's carbon footprint. "This
technology would be a great candidate for dual use in the civilian
sector if it actually comes to fruition," he said.
Spargo described another promising avenue of research that is
investigating the potential for tapping the thermal energy stored in
tropical waters.
"The energy stored in tropical waters is 300 times that of the world
energy consumption. This makes the ocean the largest solar collector on
Earth," he noted.
Ocean thermal energy conversion is a potentially efficient method to
convert the energy stored in tropical oceans into electricity.
"You take the surface water, which is about 80 degrees Fahrenheit, and
[use it to] heat a working liquid, something like propylene, which has
a vapor point below 80 degrees," Spargo explained. "That converts the
propylene liquid into a gas which drives a turbine that produces
electricity. We then bring cold water up from about 3,000 feet below
the surface, cool that vapor back into liquid and essentially create a
cyclic process."
Taking a more direct approach to harnessing the energy of the sun, the
lab is working on flexible photovoltaic panels about four times as
efficient as current solar panels. According to Spargo, the panels can
be easily folded and transported, or even integrated into materials
like tents and uniform covers to provide a local power source in
support of expeditionary forces.
"Additionally, NRL has prototyped a photovoltaic coating that can be
sprayed on surfaces, like a rock, to create on-the-fly energy sources,"
he said. "You can imagine a small force spraying a rock and using it to
generate electricity to power some device that they are using in the
field."
A more unusual approach to energy production is the use of certain
marine microorganisms that consume carbon dioxide in the ocean and
convert it into energy that can be harvested. "As part of their
biochemistry, these organisms produce electricity," he explained.
NRL has developed a number of devices that use microorganisms to power
small sensors, like bottom-moored acoustic hydrophones for monitoring
ship traffic, Spargo said.
"If we can produce enough energy with these devices, they could also
power unmanned underwater vehicles, or at least provide a docking
station where they could regenerate their batteries using electricity
produced by these microbes," he said.
The lab has expended considerable research and development into
developing hydrogen fuel cells as an energy source, Spargo said. "Fuel
cells are used to create electricity, and they do this by converting
hydrogen and oxygen into water," he explained.
Hydrogen fuel cells can deliver about twice the efficiency of a
conventional combustion engine and when used to fuel unmanned aerial
vehicles, or UAVs, they can support heavier payloads than the earlier
battery-powered models.
A recent test of the prototype Ion Tiger UAV, powered exclusively by a
hydrogen fuel cell, sustained continuous flight for 23 hours and 17
minutes.
"Also, they can operate in stealth because they're not a combustion
engine, which has a considerable heat signature, as well as a noise
signature," he said.
Spargo also described efforts to harvest methane hydrates from the sea
floor. "They have the potential of being double the amount of
recoverable and nonrecoverable fossil fuels," he said.
Spargo admitted that there are many challenges to harvesting methane
hydrates, including locating them and accessing them at such great
depths, but it would be worth the effort.
"If we're able to actually extract these from the ocean floor, there's
a potential to meet our national natural gas needs for about a hundred
years," he said.
"Energy research is a key priority for the Navy and, for that matter,
all of us," Spargo said. "I'm certain that there many exciting
discoveries ahead that will help us achieve this goal of energy
independence, as well as being good stewards of the environment as we
operate and live in it," he said.
Bob Freeman (AFPS)
# END
