Feature 7
Type 45 destroyer. Due to its size, the North Devon. The project is making
power distribution system is particularly significant progress on infrastructure US Navy Secretary
complex and uses advanced electrical preparations and a wide range of announces ambitious
protection technology. equipment procurements. Sub-contracts energy goals
Construction of the QE class began for well over half the materials and
in December 2008 with pre-fabrication equipments required, by value, have
of steel at the Appledore shipyard in already been let. WT Saying he was committing “the uS
navy and Marine corps to meet
bold, ambitious goals,” the uS
Coastguard vessel converts
Secretary of the navy, ray Mabus,
recently announced five energy
from mechanical to hybrid
targets for the forces at a specially
convened naval energy forum.
propulsion
Those targets, the navy Secretary
said, include changing the way the
uS navy and Marine corps award
contracts during the acquisition
Harstad’s varied
process to consider the lifetime
roles made her
energy cost of the system; by
well-suited to
2012, creating a ‘Green Strike
the use of hybrid
Group’ composed of nuclear
machinery.
vessels and ships powered by
biofuels and deploying that fleet
by 2016; and by 2020, ensuring
at least 40% of the uS navy’s total
energy consumption comes from
alternative sources.
“leading change is not new
for the Department of the navy,”
said Mabus. “We are a better
navy and a better Marine corps
for innovation. We have led the
world in the adoption of new
I
t can be worthwhile to convert engines and gensets, or gensets alone, energy strategies in the past. This
existing ships from diesel-mechanical can supply propulsion, auxiliary is our legacy.”
to hybrid propulsion, where a vessel’s thrusters and hotel loads. The result The forum, hosted by the Office of
operating profile justifies the investment. has been a dramatic reduction in fuel naval research and the uS navy’s
One very successful conversion has been consumption, from typically 10tonnes Task force energy, was organised
the Norwegian Coastguard vessel KV daily to 5tonnes. to introduce the Department of
Harstad. Its work covers many roles, from The related reduction in NOx and navy emerging energy strategy
emergency towing to fishery inspection, CO emissions is about 50%. One major and initiatives, and gain insight from
2
high-speed chase to loitering and contribution to this is the reduction in dialogues with participants, event
surveillance. zero-pitch losses from the propellers. organizers said. it was focused
The hybrid propulsion system on the This type of conversion can be specially around three key themes tied to
coastguard vessel now consists of the two attractive under the present tax regime in energy – security, efficiency and
main engines each driving a controllable- Norway, since it can be self funding from environmental stewardship.
pitch (CP) propeller through a reduction the local NOx tax. in addition to navy Secretary
gear. Each gearbox has a PTI/PTO with “Rolls-Royce will now put more effort Mabus, chief of naval operations
an electrical machine that can provide into converting vessels with variable admiral Gary roughead also
2250kVA to the splittable bus bar as a operating profiles, for example offshore shared his vision of the uS navy’s
shaft generator, or 1500kW as a motor supply and subsea construction vessels to energy strategy with the cross-
fed from an AFE system. Three auxiliary hybrid propulsion,” says Halvard Hauso section of representatives from
generators can be coupled to the bus. Senior Vice-President – Offshore Power federal government agencies,
Main engine power can be fed to the Electric Systems. “Hybrid conversions academic institutions, small
propellers and electrical consumers. will deliver a substantial reduction in fuel business and the defence industry.
Alternatively, a combination of main consumption and hence emissions.” WT
Warship Technology March 2010 39
WT_Mar-2010_p38-39.indd 39 23/02/2010 16:02:40
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