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To Really Cut Emissions, We Need Electric Buses, Not Just Electric Cars
An anonymous reader writes: All the EV attention these days is going to Tesla and other sedan manufacturers, but this article makes the case that it's far more important to switch our buses over to electric power than our cars. "Last year, according to the American Public Transportation Association, buses hauled 5.36 billion passengers. While usage has fallen in recent years, thanks in part to the growth of light rail and subway systems, buses still account for more rides each year than heavy rail, light rail, and commuter rail combined—and for about half of all public transit trips." This, while managing around 4-5 miles per gallon of gas, and public buses usually average about 50,000 miles per year. The electric buses themselves are significantly more expensive, but the difference is made up dramatically lower fuel costs. And there will be difficulties: "The range—up to 30 miles—limits Proterra buses to certain routes, so it's hard for an agency to go all in. Drivers have to be trained to brake and accelerate differently, and to maneuver into the docking stations. And Doran Barnes of Foothill Transit notes that some of the cost advantage of using electricity instead of diesel can dissipate. Electric cars can be charged at night, when power prices are low. But buses have no choice but to recharge in the middle of the day, when utilities often impose higher peak usage rates."
Diesel engines are powerful but they pollute A LOT. And don't forget ships. That bunker fuel many of them burn is NASTY.
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I know i'm old but there was a time when most buses ran off electricity using an overhead wire for power transfer. What's with wanting to go to battery power for this use. It's not like we could have forgotten this technology and with an update using today's technology we have to be able to make it better. Buses have defined routes so we can't argue that it limits flexibility...buses aren't cars, they don't have to be able to go down every road.
The biggest inefficiency with a (short-route) bus is stop-starting a heavy vehicle laden with people.
We have electric and hybrid buses in London, but using a Flywheel (first developed as a fuel-saving measure for F1 cars) to preserve kinetic energy has made the greatest difference to efficiency for London buses.
Shanghai has had some buses using these for several years. They recharge at some of the bus stops.
A bus will only get a few mpg, but carries a lot more people.
Sometimes it does. I see a lot of buses driving around 90+% empty.
I don't care if it's 90,000 hectares. That lake was not my doing.
I see a lot of cars driving around 80% empty. To and from work, I must admit that one of them is mine.
The largest container ships have huge particulate emissions, but that's because there's no regulation on particulate emissions according to international law. It would be difficult to change that, because regulating ships requires an international agreement. That said, it should be done.
However, ships already have extremely low CO2 emissions per ton-mile. They are already extremely fuel-efficient. The largest ships have 1/15th the fuel usage and CO2 emissions per ton-mile as a tractor-trailer truck, and massively better than your car. If you drive one mile to the store to buy an article of clothing, you have emitted vastly more CO2 than was emitted by shipping it halfway around the globe by containership.
That will have almost no effect on your CO2 emissions.
San Francisco has had a fairly extensive trolleybus network since the 1930s. Although only 15 bus lines are trolleybuses, those are the most crowded bus lines, so a significant fraction of bus traffic there is electrified.
It appears that diesel buses cost $450,000, and battery-electric buses cost $825,000, and trolleybuses cost $1m each. Trolleybuses last at least twice as long as diesel buses. The overhead wires cost $2 million per mile and last almost indefinitely, it appears, because I have never seen maintenance being performed on any of them, in contrast to roads and stoplights which are being repaired constantly, and buses which are being replaced often enough.
San Francisco has 300 trolleybuses for 15 lines, and each line is about 6 miles long. Thus the overhead wires cost $180m, the buses cost $300m, and the electricity costs $48m over 24 years. It appears that equivalent diesel buses would cost $270m and use $330m in fuel over 24 years, servicing the same routes (just using the numbers I read from an article and doing the calculation manually). It would appear that trolleybuses cost ~$528m for those routes and diesel buses would cost ~$600m. However, that's not taking into account financing costs etc, which would probably make the trolleybuses more expensive than diesel ones since the upfront cost is higher. Also, this is for routes in San Francisco which are only 6 miles long; the economics may change for suburban routes.
That said, it doesn't seem like the costs are very different whether we choose trolleybuses, diesel buses, or battery-electric buses. It may be slightly more expensive to go electric, but not much.
Answer:
88% of CO2 travel footprint is generated by cars, 1% by buses.
They're called trollybusses and lots of cities used to have them. Apparently hundreds of cities in the US had them but most of them went away in the 1950's and 1960's. Currently they're only in use in Boston, Dayton, Philadelphia, Seattle, and San Francisco (List of US Trollybusses). I was recently in San Francisco on a tour bus and they said the reason they use them is the electric motor has more torque which is needed to go up the steep hills. I can't speak for why they're still in use in the other cities or why they went out of style in all but 5 cities. Growing up in Dayton I thought they were more common than they are since Dayton isn't that big of a city compared to the others on the list.
I see a lot of cars driving around 80% empty. To and from work, I must admit that one of them is mine.
You wastrel... At least my Ferrari is only 50% empty!
The US Navy has been all-in with Nuclear power. R&D has been non-stop. If they haven't "solved its problems", it's unlikely throwing even more money at it, would do so.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
Seriously? Do you really believe a bunch of hippies put the breaks on something as profitable as Nuclear power?
Coal and oil lobbies, the folks paid to store nuclear waste instead of processing it into new power. Look at those folks. Follow the money. When anything of importance happens it's always money.
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Wrong !
In many ways, military and civilian water cooled reactors of today should have been 40 years ago technology.
Basic Nuclear in the USA research pretty much stopped in the late 60s during the Nixon administration.
The really sharp, ambitious nuclear scientists (from the Manhattan project), wanted either metal cooled fast reactors or thorium molten salt reactors.
Nobody wanted a water cooled reactor. A water cooled reactor was the Navy's solution to the Navy's problem with Navy's knowledge set.
Plus lets compare the world's largest Navy nuclear reactor.
The latest nuclear carriers use 2 A1B nuclear reactors, rated at 300MWt each.
And those reactors run around 50% power most of the time.
A full sized civilian reactor usually is 4000MWt (1300-1400 MWe).
Very, very different beasts.
The navy doesn't need inherently safe reactors, they have extremely competent officers running its nuclear reactors.
Civilians need inherently safe, walk away if anything goes bad, reactors.
With molten salts we can built 500-1000MWt reactors that are far safer AND far more efficient than the 4000MWt water cooled reactors.
I have spent over 200 hrs studying lectures, papers, analysis, for molten salt tech.
And why they were never seriously pursued. No technical reasons. Political reasons instead.
While I prefer molten salt reactors over sodium cooled fast reactors, the later are also way safer than water cooled reactors. Killed in the 90s by Clinton, Al Gore and John Kerry. By order of big coal and natural gas interests.
If you want nuclear research to restart, we first need to combat the real enemy of nuclear power today which is the public, that was carefully fed lie after lie about nuclear power, and the BIG lie that solar+wind can do the trick (THEY CAN'T).
A 30 mile range? What kind junk are the buying?
A BYD electric bus has a nominal range of 155 miles. It sounds much more reasonable to me.
a,e,i,o,u and sometimes w and y (at be if of up cwm by)
Here's what the US National Academies have to say: "One might think that airplanes, trains, and buses would consume most of the energy used in this sector but, in fact, their percentages are relatively small--about 9% for aircraft and about 3% for trains and buses. Personal vehicles, on the other hand, consume more than 60% of the energy used for transportation."
Completely eliminating emissions from buses would make only a small difference in the big energy picture.
That said, electric buses might not be such a bad thing. I'm driving an electric car these days and it is awesome (even if it isn't a Tesla).
Nuclear power has already been tried on a merchant ship.
The problem is the manpower to operate it just doesn't scale well to something as small as a ship. The reactor itself scales just fine and performed admirably (used about 163 pounds of uranium or a hair over one gallon, instead of 29 million gallons of fuel oil during its 10 years of operation). But the additional manpower and training needed to operate and maintain a nuclear reactor instead of a diesel engine killed its cost-effectiveness at transporting cargo. You're basically using the same amount of trained staff as needed to operate a reactor to power a small city (a few hundred MW), except you're only powering a ship (74 MW).
Maybe molten salt reactors or some other tech will be easy enough to maintain that nuclear could supplant diesel for cargo ships. But it isn't going to happen with light water reactors. Even the U.S. Navy sees this lower limit, and uses diesel or gas turbine engines in anything as small as a cruiser (the previous Virginia-class cruisers were nuclear, but the current Ticonderoga-class uses gas turbine engines).
The problem is the manpower to operate it just doesn't scale well to something as small as a ship.
Why is it then possible and viable to have nuclear powered submarines but not ships?
Economically, it should not be. Because the value metrics and usage requirements for a submarine are vastly different to those for a ship. Both go on water, but when a submarine is underwater it needs a controlled non-toxic emission propulsion and power system - older and smaller subs use electric batteries, which are charged when on the surface by a diesel engine which exhausts out into the air, so they have very limited underwater endurance. A sub with a nuclear reactor does away with the electric battery element, has no need of diesel engines, so it can stay underwater for months at a time - even to the point where they can if necessary complete an entire tour of duty without breaking the surface of the water.
That ability to stay underwater and (probably) undetected gives the ability to project power into areas and in ways where highly visible surface ships just would not work.
The reason it works is that submarines are not used for economic activity - their value to the Navies that have them falls into the "money is no object" category and profit is irrelevant in the face of security and force projection.
Why is it then possible and viable to have nuclear powered submarines but not ships?
The navy does not expect its submarines to operate at a profit. This is partly because they know that the market for nuclear missile-generated craters is fickle, so their sales are going to vary dramatically from year to year, include whole decades at a stretch where they may not deliver even a single warhead. It is partly because their other principle cargo, national influence, is very hard to value objectively. Most companies carry this product as "goodwill," and serious accountants completely disregard it in valuations.
The whole business model of nuclear submarines is a sham. A ponzy scheme foisted off on a credulous public awed by technology and investor story time, run by directors spending other people's money, but guaranteed to collect their own luxurious salaries regardless of whether the business ever turns a profit. 50 years without delivering a single megaton warhead...you'd think investors would wake up.