Navy Spends $33 Million For Hybrid of the High Sea 210
Posted
by
samzenpus
from the batteries-not-included dept.
from the batteries-not-included dept.
coondoggie writes "Some might call it an enormous floating Prius, but others will call it a step in the right direction: A new hybrid electric engine for US Navy ships that promises to save up to 12,000 barrels of oil a year per ship.
The folks who brought you the Predator unmanned flying aircraft, General Atomics, this week got $32.7 million to develop a proof-of-concept Hybrid Electric Drive (HED) system for a full-scale demonstration on board the Navy's DDG 51 Class destroyers.
DDG 51 destroyers are powered by General Electric gas turbines capable of moving the ships along at over 30 knots or about 35 mph. The General Atomics system would meld into this system and let the ship use electric power for slow-speed maneuvers. The engines would provide more power as the ship needed to go faster."
Re:So that's where our tax dollars go. (Score:5, Informative)
Re:So that's where our tax dollars go. (Score:2, Informative)
Installation of hybrid drivetrain is a onetime cost. The fuel savings go on for the entire time it is in service.
Other benefits are: Less logistics required to supply a fleet group with fuel during operations. And the logistics in itself uses a fair amount of fuel too. So you've been looking at this with a rather narrow perspective, and very short-term.
Re:Submarines (Score:5, Informative)
Um, the Navy sort of does. Every nuclear submarine out there has a big diesel engine and an array of batteries on it. They are for use when the big tea kettle is down for maintenance and/or emergency situations.
Re:So that's where our tax dollars go. (Score:5, Informative)
Re:Not exactly a new idea (Score:1, Informative)
Queen Mary 2 anyone?
http://en.wikipedia.org/wiki/RMS_Queen_Mary_2#Power_plant_and_propulsion_system
Also, strategically (Score:4, Informative)
It is also an important strategic advantage to have a ship that is more fuel efficient as it can stay in the arena for longer before it needs to be refuelled.
This is likely a main driver for this research.
Re:Submarines (Score:2, Informative)
Re:Nice thing. (Score:5, Informative)
in this particular case, the Daring class destroyers also use a combined gas and steam turbine to generate the electric power required for propulsion, thereby improving fuel efficiency.
the interest in electric propulsion is mostly due to other factors, tough: lower heat/sound signature, higher efficiency at slow speed etc.
Re:Nice thing. (Score:5, Informative)
Re:Too bad we don't have this already (Score:1, Informative)
U.S. nuclear submarines are propulsed using steam power, not electric.
"The Russian, U.S. and British navies rely on steam turbine propulsion, while the French and Chinese use the turbine to generate electricity for propulsion (turbo-electric propulsion)." [http://en.wikipedia.org/wiki/Nuclear_marine_propulsion]
Re:Too bad we don't have this already (Score:2, Informative)
With more than 5500 reactor years without an accident
http://en.wikipedia.org/wiki/USS_Thresher_(SSN-593) [wikipedia.org]
http://en.wikipedia.org/wiki/USS_Scorpion_(SSN-589) [wikipedia.org]
different type of hybrid (Score:4, Informative)
What the Navy means by 'hybrid' is not exactly what you'd expect. TFA is light on details, but I suspect the idea is to use the electrical generators on the ship for low-speed propulsion, instead of having to run the main gas turbine engines at 10% load, at which they're very inefficient. There'll be no batteries involved, and no regenerative braking.
Many warships already have two plants capable of driving the propellers. Not so much the USN, but European navies often use gas turbines to provide high speeds (30+ knots), plus a set of diesels for lower speeds (up to 20 kt).
For new ships, electrical propulsion is being looked into for the same reason: you can switch generators on and off so you always have them running at their most efficient power setting.
Re:What would happen... (Score:4, Informative)
If you check out the Journal article [wiley.com], they describe this system as an electric motor mounted on the drive shaft, powered by existing auxiliary electrical generation capacity on the ship. The motor would only be used at speeds under 12kt at maybe 1/10th peak power output, when the efficiency drops off considerably and the turbines are basically idling. The system would be set up to run in reverse, providing power back to the ship, presumably for future electric artillery that the Navy is developing.
Re:What would happen... (Score:3, Informative)
Lithium batteries currently in production aren't rechargeable, so I doubt they would use them. Lithium-ion batteries don't contain metallic lithium (unless they are malfunctioning), so breaching them shouldn't be particularly interesting.
Re:Too bad we don't have this already (Score:4, Informative)
12,000 barrels is not alot (Score:1, Informative)
(Posted as AC because at work)
I was on a DDG. A full fuel load is somewhere between 400,000 and 450,000 of DFM (Diesel Fuel Marine) I believe the Nato term is F-76 of F-45 for this type of fuel but don't quote me on that, the memory is slipping. On a full power run, all 4 gas turbines engines online and the throttles set to full forward, we burn about 100,000 gallons an hour. This is extremely rare as it is wasteful. Only done for periodic testing of the ships systems, and when the ship really has to haul ass (imminent combat or other special circumstance require full speed with full reliabilty.) Normally the ship "steams" on one or two engines, and consumption if I remember can go down to something like 500 gallons per hour. Steaming across the sea at 20 knots with two engines running we burned something like 6k an hour but again I dont remember exactly. Saving 12,000 barrels in one year, which is 500,000 gallons according to Wikianswers, does not seem significant to me. But I guess it is something. Oh, but then the costs have to be counterbalanced with the cost of retrofitting the propulsion systems with an electrive drive, and the maintenance and repair costs on the said electric drive, and the additional training of ships crew to work with the new equipment. And also I would say the additional people onboard because of the extra equipment but, haha, im laughing inside, the Navy wouldn't do something like that, they would just pile more work onto already overworked engineers.
Also on a side note the generators providing electricity for the ship run on the same fuel. I guess the savings is allowed to happen because the generators are more efficient at generating electricity, sending it through the ships electrical distribution system, and powering an electric drive at certain shaft speeds, than the engines themselves are at those same speeds.
Re:Nice thing. (Score:3, Informative)
Re:Nice thing. (Score:5, Informative)
Except that a lot of the sound comes from the propellers alone.
Not in the way you think. The propellers are the point of contact with the sound transmission media - water. The propeller connects with the drive shaft and transmission. The transmission connects with either an electric motor or an engine. And in some cases, multiple engines and/or motors. The vibration and and engine noise is then transmitted through the transmission, the drive shaft, and then propeller, where it is then transmitted into the water for all to hear. This is the primary reason many military vehicles have been heading toward an electric drive system where the ICE is used to turn a generator rather than directly drive the propeller. This is also the reason modern diesel subs have been getting so quite.
In short, the propeller on modern military ships make the vast majority of their noise because they are a transmission point for everything mechanical attached to it, not because its spinning in the water. Which means, using electric motors to spin your propeller, especially at slow speeds can make you incredibly stealthy despite the fact a propeller is still spinning in the water.
Re:Not exactly a new idea (Score:3, Informative)
German U-Boats in in WWII had dual diesel/electric engines.
Essentially all submarines in WWII had dual diesel/electric engines, and basically any non-nuclear submarines today do, as well. Earlier than WWII, the electric side was standard on all but the earliest impractical prototypes, and the other propulsion was experimented with until everyone settled on using diesel train locomotive engines.
That wasn't for efficiency, but because they couldn't use the fuel-burning engines underwater.
Re:Nice thing. (Score:5, Informative)
Yes, you hear propellers below cavitation speed. Thirty tons of brass doesn't move hundreds of tons of water "quietly". Another sonar operator can hear it from miles away. Standing in after steering, the propellers are quite loud all the time, and very loud any time they make a change in speed. I spent many an hour standing watch in that smelly little room. (and after all that time, I never figured out why it was always so freaking SMELLY!)
So far, I've not seen anyone mention one of the biggest benefits of electric power. Torque. When you flip the switch and/or turn the rheostat, you have power NOW! Gas and diesel are quite slow to build up torque, even in the turbine engines that the Navy uses. Boilers are somewhat better - depending on whether you've already built up a head of steam or not. If not, you're still dependent on turbines spinning up to bring oxygen to the fire. With electrons, there is no perceptible delay.
The result? Sonar hears a torpedo coming in, the port screw is put into full reverse, starboard screw is full forward, and the ship spins (not turns, but spins in place) in about a minute, instead of 4, 5, or 6 minutes.
Alright, today's enemies aren't likely to have torpedos, but the maneuverability can be just as valuable in many other situations - including entering and leaving port when some idiot on a ski boat ignores the rules of the road.
Sails are no laughing matter! (Score:3, Informative)
http://www.google.com/search?hl=en&q=sky+sail&aq=f&oq=&aqi=g10 [google.com]
Cheers.
Re:Nice thing. (Score:3, Informative)
Re:What would happen... (Score:3, Informative)
I thought the new destroyers were also nuclear.
DDG-51 destroyers are Arleigh Burke class. There's 55 of them so far; none are nuclear powered.
Rep. Gene Taylor made some noise about canceling the Zumwalt/DDG-1000 class (gas turbine-powered) in favor of a nuclear Burke variant, but it hasn't happened.
Wasn't there a big show of the all nuclear carrier group that could go around the world with having to refuel?
What you are referring to is 1964's Operation Sea Orbit [wikipedia.org]. You need more than a carrier and two missile cruisers to make up a carrier strike group. Nuclear-powered destroyers and supply ships were not built, and the all-nuclear Navy never materialized.
Since the last nuclear cruiser was decommissioned in 1999, the only nuclear vessels in the US Navy are aircraft carriers and submarines.