Ultracapacitor Bus Recharges At Each Stop 419
TechReviewAl writes "A US company and its Chinese partner are piloting a bus powered by ultracapacitors in Washington DC. Ultracapacitors lack the capacity of regular batteries but are considerably cheaper and can be recharge completely in under a minute. Sinautec Automobile Technologies, based in Arlington, VA, and its Chinese partner, Shanghai Aowei Technology Development Company, have spent the past three years demonstrating the approach with 17 municipal buses on the outskirts of Shanghai. The executive director of Sinautec touts the energy efficiency of this approach: 'Even if you use the dirtiest coal plant on the planet [to charge an ultracapacitor], it generates a third of the carbon dioxide of diesel.'"
Re:Isn't this the same as a trolley? (Score:5, Interesting)
We have trams (light rail) here in Melbourne. Maybe if you ran the numbers you could take away the overhead cables from most of the network and just charge the trams at stops and intersections. Might be cheaper overall that way.
Re:soundes extremely dangerous (Score:1, Interesting)
Re:Until... (Score:5, Interesting)
nice tin foil hat.
Here's a real world example http://greentransportandenergy.blogspot.com/2009/03/great-importance-of-wheel-motors.html [blogspot.com]
They had a working prototype, they approached Detroit to get their making-cars expertise... and the project gets quickly scrapped for no apparent reason.
No US company involved here.... (Score:4, Interesting)
Sinautec, as I suspected, is a Chinese firm, with an office in VA.
http://www.sinautecus.com/contact.html [sinautecus.com]
Re:No, thanks (Score:5, Interesting)
The cap's are under the seats?! Call me old fashioned (and it won't be the first time) but I'll take a cab, thank you.
"You can't get people to sit over an explosion."
--Colonel Albert A. Pope, 1890s bicycle and electric car mogul, on the newly introduced internal combustion engines.
Re:Until... (Score:5, Interesting)
So what they need to do is reduce the weight of these independent motors, or find a way to place the suspension within the wheel assembly itself. Some kind of circular leaf spring assembly comes immediately to mind. Imagine a wheel axel, surrounded by springs rather than hard 'spokes' that connect it to the rubber.
Kind of a 2 state suspension system with a small leaf spring system between the actual rubber and the motor, and then a heavier duty suspension between the axels and the rest of the car.
An invention from University of Texas at Austin (Score:5, Interesting)
http://www.utexas.edu/research/cem/Energy%20Storage%20Composite%20Rotor.html [utexas.edu]
The University of Texas at Austin Center for Electromechanics (UT-CEM) has developed a 2 kW-hr flywheel battery for energy management on a hybrid electric urban bus. The battery will recover braking energy and store excess energy generated by the prime mover. The flywheel rotor, fabricated from high-strength composites, spins at 36,000 rpm at full charge (~825 m/s tip speed), and is housed in a vacuum enclosure to minimize windage drag. A cross-section of the flywheel system design is shown. Ensuring flywheel safety is a major issue that must be addressed in using flywheels for transportation applications. In support of this activity, the durability tests performed under Phase IV of the DARPA Flywheel Safety Program, focused on this flywheel design.
Re:Until... (Score:3, Interesting)
From working with industrial automation, I can tell you that trying to synchronize motion between two independently controlled electric motors, with independent loads, is a nightmare. With modern control hardware we are getting better, but we are not there yet. In 1995, I sure that the could make it look good for some tests, but there was no control system fast enough or smart enough to handle it.
Without even looking at the automotive side, i would kill to have a system that can manage multiple electric motors with rapidly changing load conditions for long periods of time without freaking out. The possibilities for material handling systems and machine tending systems make me drool.
It was killed because Detroit couldn't make it work. The idea of wheel mounted motors gets kicked around a lot, because it does have a lot of merits, but there are too many technical problems that need to be worked out yet before it becomes viable.
Re:Until... (Score:5, Interesting)
as a engineer having worked on mining trucks for 12years with wheel motors, that page seams very guilty of avoiding context. Komatsu (mostly GE), Liehbier (Siemiens+GE), and Caterpillar all have wheel motored mining vehicles in production. 1) They show no gearing reduction, electric motors are generally very in-efficient at high torque, they mostly run at around 40:1 reduction in real world car app, this kind of gearing reduction is very pricey to create for high torques without lots of space. 2) Electric motors require a very large current to produce those torques (especially if no gearing reduction) and/or lots of windings (lots of weight) big wiring, and difficult power supplies 3) they show no room for excitation of the rotor, this means permanent magnets = rare earth magnets = $$$ + dense weight. 4) very small bearing surface area, lots of spinning mass = lots of momentum = lots of torque when turning, bumps, etc. Front wheels sounds like a very bad idea. 5) single efficiency number is suspicious, as stated above torque is poor efficiency, I do believe the efficiency at higher speeds but not at high torque. 6) sealing against weather/dirt/mud. Even if they get only 4% loss, good luck with cooling that and sealing it at the same time, without dumping the heat into the tires which will already be under trouble (see the suspended weight = extra tire abuse) 7) still no economical battery choice that can make electric cheaper than diesel over the lifetime of a battery.
That said, I want 2 for my 1970 2WD truck. It has room for them, and I could slap them on get regen braking, and emergency 4WD help. I don't need much help, and since 80% of braking energy is slowing from 75mph to 25mph so I don't care about the torque/efficiency from 25 to 0.
Re:An invention from University of Texas at Austin (Score:4, Interesting)
Think it'll work this time [wikipedia.org]? I kinda prefer the "solid state" nature of the capacitors.
Re:Isn't this the same as a trolley? (Score:4, Interesting)
Perhaps I'm looking at it wrong but I look at it as saying the use of trolleys attracts economic development like the parable of the broken window, by breaking a window glass you're creating work for the glass maker. However in reality breaking the glass only diverts money when it can be used for a better purpose. Instead of the kid getting the shoes he needs the money is now spent on glass.
That's not exactly true. The economic development argument states that the presence of a streetcar line increases foot traffic in that area, which tends to increase the customer base for local businesses. Its a small scale version of the argument that justifies the presence of highways. By making transportation easier (via infrastructure improvements) the government allows commerce to flow more quickly and cheaply, increasing economic activity by reducing transaction costs.
How...... (Score:3, Interesting)
Petroleum diesel C16H34 or C14H30
Coal Errrrrr C with variable trace quantities of S, H, O and N.
Subcritical fossil fuel power plants can achieve 36–40% efficiency. Supercritical designs have efficiencies in the low to mid 40% range, with new "ultra critical" designs using pressures of 4,400 psi (30 MPa) and dual stage reheat reaching about 48% efficiency.
Ideal diesel efficiency of 56%, but lets stay sane, I keep hearing more along the lines of 35% (Probably BS but real numbers have been banished/obfuscated/hidden somewhere)
Factor in 15% to 50% (extreme) grid transmission loss, and (ops) 5% to 10% electric motor loss.
Love the idea of a Ultra Capacitor for a Hybrid, just stop saying silly things. Less CO2, you're funny.
Re:Until... (Score:5, Interesting)
I actually asked a fellow I know who works at Tesla about wheel motors. He basically said it's a bad idea from a performance and handling point of view. The additional weight in the wheels makes the suspension less effective and means that the effect of going over a bump will be a lot harsher. Besides, he said it also would add a lot to the cost since now instead of one motor you need two or four, as well as two or four inverters and a lot more complicated control software. This also would add more weight since each motor needs its own set of magnets and housing. Cooling can also be a problem. It's much cheaper to just use a differential and axles which typically have very little loss with the advantage that the weight is shifted to the car body. It also makes it easy to do things like water cooling for the motor. I suppose one could still use multiple motors located in the body and use axles to get rid of all of the mass in the wheels, but it still adds a lot of unnecessary complexity to the control system and additional cost and less reliability.
The new terrorism (Score:2, Interesting)
Now blowing up a bus might be as easy as cross wiring the charging terminals.
Their CO2 claims don't make sense to me (Score:2, Interesting)
From http://en.wikipedia.org/wiki/Greenhouse_gas:
Fuel name CO2 emitted (lbs/106 Btu)
Fuel oil 161
Coal (bituminous) 205
Coal (subbituminous) 213
Coal (lignite) 215
Coal (anthracite) 227
From http://en.wikipedia.org/wiki/Internal_combustion_engine#Energy_efficiency:
"most engines retain an average efficiency of about 18%-20%"
From http://wiki.answers.com/Q/What_is_the_energy_efficiency_of_an_average_coal_powered_plant:
"According to Hans-Dieter Schilling (Energie-Fakten), the average efficiency of all coal power stations in the world currently stand at around 31%"
Mashing those numbers around a bit I get around 900lbs of CO2 per usable MMBTU from diesel (fuel oil, close enough for these rough numbers), vs 700lbs of CO2 per usable MMBTU from coal based electricity. That's not even 1/3 less, far from the 2/3 less they are claiming.
There are extraction/transmission/conversion losses in both cases that could be factored in, but it's hard to see how it could change their math by a factor of two.
Am I missing something obvious?
How would it provide heat? (Score:2, Interesting)
Would they have another bank of capacitors for resistive heating?
What if the bus gets stuck in snow and runs out of charge? will the snow and slush cause problems with the charging contacts?
Trolleybusses seem a lot more practical to me, I never understood why they are so unpopular in north america, even if only used in high density areas, where the infrastructure would pay off.
Re:An invention from University of Texas at Austin (Score:3, Interesting)
Flywheel energy storage is far more feasible for larger scale storage in a fixed position power applications (eg. home, light commercial, and industrial.)
In a high speed collision, if the containment vessel is breached, a flywheel can become an autonomous buzz-saw with a kill radius of several miles. Even worse, if such a breach occurred in a traffic jam, and one flywheel hits other vehicles liberating more flywheels, it would result in a chain reaction that could level an urban or suburban community.
One possible solution, might be some way to discharge the flywheels energy quickly in the case of the car's sensing a collision. Maybe an active circuit that quickly drives the flywheels energy into a different storage device... like a super capacitor?
The fat guy sang too Re:Until... (Score:3, Interesting)
http://www.gizmag.com/michelin-active-wheel-production-electric-car-by-2010/10489/ [gizmag.com]
Re:Isn't this the same as a trolley? (Score:3, Interesting)
A trolley/streetcar line reduces the vehicle capacity of the road it travels along.
How? You can pave the area around the tracks [wikipedia.org].
if driving is sufficiently difficult suburban dwellers (like me) will choose to stop going downtown rather than put up with the inconvenience of massively crowded streets.
The city dwellers already have streets crowded with your cars. Every extra person in a tram (rather than their own car) is more road space for you!
Make a brittle flywheel (Score:3, Interesting)
Make the flywheel brittle - like a ceramic or like those shotgun rounds that disintegrate when breaching a door. That way if containment is breached, it turns into powder.
Re:Make a brittle flywheel (Score:3, Interesting)
This is how modern flywheel energy storage [wikipedia.org] works. The rotor is typically made out of carbon fiber or a composite thread wound around a shaft - if the rotor's integrity is lost, it turns into red-hot slag instead of leveling half a city block. Even so, most large flywheels are in a bunker underground encased in several feet of concrete. For it to be safe in a vehicle the containment vessel has to be very strong and also lightweight - which means it'll be expensive, unfortunately.
Re:Make a brittle flywheel (Score:3, Interesting)
For [a flywheel] to be safe in a vehicle the containment vessel has to be very strong and also lightweight - which means it'll be expensive, unfortunately.
Research in this area has been encouraged within the space of F1 motor racing. The aim is exactly that if there is a containment breach (relatively likely in a crash in F1, which isn't exactly the world's safest sport) then the flywheel turns to dust rather than killing the driver. Something like that sounds like what's needed for the bus application...
Re:An invention from University of Texas at Austin (Score:3, Interesting)
I maintained a smaller, IBM drum unit, mounted on a military plane. I often wonder what it would be like to work on a modern implementation. Imagine, zero seek times, less than 1ms access times, and parallel reads possibly from every track at once (if the bus would allow it).
The system I worked on was a whopping 12Mhz minicomputer... and it's 60's era drum unit was actually faster than any magnetic storage available today (for random reads and writes), I did the math once and it could sustain well over 200MB's (if every track were read at once); not that the system could feed it data that fast or that it had that much capacity.
Fun read: http://www.tpub.com/neets/book22/92d.htm [tpub.com]
Don't even get me started on the core memory that was later replaced with bubble memory. Though I do miss the days of a computer maintaining it's state when power is removed.
It's kind of amusing how we have gone backwards from those days. MRAM always seems to be a few years away and in the meantime if the power goes out, we lose everything. Even in the 60's this wasn't the case.
Re:Until... (Score:3, Interesting)
1. Exxon "owns" 1% of the world's reserves and produces only 3% of the world's oil. Astonishing as it may seem, they are really bit players compared to the big national oil companies. Even if they wanted to, Exxon couldn't have lowered the price of oil in the market overall. As far as showing interest in green energy, my opinion is that it's their choice on what they want to support, what they consider a good investment for their money. Many oil companies (most notably Shell, Chevron and BP) made a big deal about their investments in "green energy", but if you actually look at it most people come to the conclusion it's just greenwashing. Would you rather Exxon tried to deflect criticism similarly, or that they stick to reality: they are an oil company, their competitive advantage in the world is producing oil and that is what they should continue do, in the interest of their stake holders and everyone that uses oil and gas products?
2. See point 1. regarding green energy. Regarding OPEC, I'm not sure that means what you think it means.
3. This looks like an internal squabble between gas stations and their franchise owner. I'm sure this sort of thing happens to companies all the time, and I'm sure Exxon and its lawyers will sort it out correctly.
4. and 5. I don't believe Exxon executives are convinced global warming is actually caused by the burning of fossil fuels. And they're certainly not alone in that, and they certainly have more motivation to be skeptical than any other private company in the world. That said, I agree that their efforts to spread their skepticism were clumsy and in some cases not particularly honest.
6. That does not seem to be what the article you link says. It says that Exxon told its service stations not to use MTBE in areas where their are drinking water wells. The service stations used it in some of those areas anyway. Those areas are found to have MTBE contamination. Exxon says that, while their stations used MTBE, that they were not the source of the contamination (or at least not all of it) and they shouldn't have to pay to clean up other peoples' mess just because they have the deepest pockets.
7. and 8. Big business make campaign contributions to friendly American politicians all the time. It's unfortunate for democracy, I agree, but you I don't see how you can take big oil to task without looking at all the others: pharmaceuticals, agriculture, manufacturing and so on.