The return of the steam locomotive

[Bytesmiths]

Large coal-fired electricity generation attains about 35% to 40% Carnot efficiency, at the plant. Transmission losses can be 10%.

Siemens / EON plan to build a coal fired power plant with >50% efficiency in 2014 (700°C steam temperature).

Wow, that's pretty darn good. I was not aware of any external combustion technology that could surpass 50%. This internal combustion engine is also in excess of 50%, which is the best I had heard of for any heat engine.

(average efficiency of coal fired plants in Germany is 38%)

And I think Germany is far ahead of North America in that regard.

Transmission loss also depends on the grid structure.

That's certainly true. My 10% number came from a talk by some green planner for a local utility in Oregon. I think transmission lines (and thus losses) tend to be longer in North America than in Europe.

[Gerben]

New coal power plants can use gasification technology. That allows the use of a combined cycle like with natural gas fired power plants. This makes power plants more flexible and increases their efficiency to approach that of gas fired combined cycle plants. The cost however are still too high, mainly because the technology is still experimental. And coal is still too cheap.

[Revi]

I love steam engines, but I agree that a hybrid electric engine seems to be the best way to move a train. We went on a run from Brunswick, Maine to Rockland a couple of weeks ago. What a great day. The best was when we could get to the back of the train and watch the tracks recede in the distance.

They are talking about extending passenger rail to Augusta, Maine. That would be great.

There used to be lots of narrow gauges. Some are still around.

We took a ride on the Wiscasset, Waterville and Farmington Railway. It's the best little railway in Maine.

http://www.wwfry.org/

We used to be able to take the train to the Commonground Fair, but they aren't in business any more. It really added to the car traffic at the fair this year.

I hope Obama pushes rail service. If he gets one thing done that would be the thing to do.

[Bytesmiths]

I agree that a hybrid electric engine seems to be the best way to move a train. We went on a run from Brunswick, Maine to Rockland a couple of week..

Keep in mind that a "hybrid electric engine" is not at all like a hybrid car, and should more correctly be called a "diesel-electric" engine, since power transmitted to the axles is not a combination of chemical and electrical power, as it is with hybrid cars.

From a workshop I took when I was a consultant to PTT Switzerland (who run the trains there), my understanding is that the diesel-electric engine design is primarily because electric speed control at high power is easier to achieve than mechanical speed control.

The diesel runs continuously at optimum RPM, driving a generator, which then goes to a switch box that controls speed by a combination of putting huge resistors into the circuit between the generator and the trucks, and switching the trucks into different winding and series/parallel configurations. (The large, flat, finned boxes with fans on the tops of locomotives are the resistor packs.)

When decelerating, the trucks do use regeneration for dynamic braking, but send their energy into the resistor packs to be dissipated, rather than into a battery.

Except when operating at full speed, this design is not particularly efficient -- at half-speed, for example, fully half the power could be dissipated in the resistor packs -- but it is cheaper to manufacture than building an automatic transmission capable of handling the peak torque of a 2,000 horsepower diesel engine. And diesels travel at full speed most of the time, anyway. (It's much more complicated than this simplistic example. You could travel at half or quarter speed at full efficiency by switching the trucks into different series/parallel combinations, but my point is that some dissipation of energy via resistor packs happens from time to time.)

Switzerland has a nation-wide electric rail system, so their trains are almost completely electric-only. They do save energy with regenerative braking, by boosting the EMF in the field winding to the point that the energy from braking is fed back into the track. But without huge, expensive, heavy batteries diesel-electric trains cannot possibly store braking energy without a mechanical "battery" using a flywheel. I'm not aware of any that do such a thing.

[JudgieReloaded]

I believe even China since it's huge growth-spurt, has had it's steam loco's moth-balled for at least a decade now.

[mos6507]

There is some work being done now to create true serial hybrid trains with batteries onboard to capture the regen. The same concept would work for pure electric trolleys.

[criticalmass]

Regen is kind of useless in locomotives it seems. Hopefully, this is where supercapacitors will come in extremely handy in the near future.

Kind of difficult to beat electric power for sheer efficiency, isn't it?

Still, I'm like an 8 year old when I get the chance to even touch a steam locomotive. The Baldwins were my favorites and I've been studying them very closely in the event I ever need to power something with steam.

[Bytesmiths]

There is some work being done now to create true serial hybrid trains with batteries onboard to capture the regen.

I sure would like to see a reference -- got any?

This just doesn't make sense to me. You'd need about 100 times the battery as you have in a typical electric car, for the same driving range of 50-100 km.

On the other hand, if you have an electric train system, you have someplace you can feed the energy -- no batteries needed.

Rather than put all that money into batteries, why don't they simply adapt the system to electricity? The wires over the track could be connected to the national grid, so that trains going downhill could put electricity into the grid, and all-electric trains -- no diesel at all -- could run off of wind/hydro/solar (or coal).

Hopefully, this is where supercapacitors will come in extremely handy in the near future.

That would be nice, but people have been working on these for a long time. Do you have any references for recent breakthrough research?

This seems to me like "denial" thinking -- if we only are smart enough, we'll escape Peak Oil somehow.

[criticalmass]

Ultracapacitors "Supercapacitors" already exist. They just don't store energy in the manner that batteries do. (Les Ah, more flexibility) What they can do is store a large, readily available charge to provide power for the trip back up the hill. The major advantage: smaller, lighter, and they can charge and discharge rapidly. Ultracapacitors can also cycle thousands more times than batteries. So where you could only capture a fraction of charge from regen with a battery pack, ultracapacitors could capture almost all of the regen quickly and dump the power right to the electric motors the moment it is needed for a big surge.

[Blacksmith]

Bill Lear of Lear Jet fame in his later years worked on an external combustion engine for a while. I don't know the specifics but I know they could never achieve the efficiency of the internal combustion engine.

[Bytesmiths]

Ultracapacitors "Supercapacitors" already exist.

And they have a long way to go in order to be practical. Their energy density is only about 1/5,000th that of diesel or gasoline. That means that the travelling range you'd get from just 100 kilograms of diesel will require 500 tons of ultracapacitors.

When I was a practising EE in the '70's and '80's, ultracapacitors were not much different than they are now, which leads me to dis-believe that they're going to get 5,000 times better any time soon.

The major advantage: smaller, lighter...

Simply untrue, by a factor of 125 (compared to lithium-ion batteries), or 2,380 (compared to diesel fuel), according to WikiPedia.

It's not that I don't think they should be studied, researched, and improved, but today's versions are no magic bullet, and tomorrow's versions that would do all the wonderful things you claim aren't even on the drawing board.

[vaseline2008]

There is some work being done now to create true serial hybrid trains with batteries onboard to capture the regen. The same concept would work for pure electric trolleys.

Here's the GE Locomotive Website. Enjoy.

GE Locomotives

GE Hybrid Locomotive PDF Link