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Power Plants On Rails for California
SoCalChris writes "According to this article on Wired.com, the Sierra Railroad is planning to use diesel train locomotives to produce power for California. Each of the 48 engines are expected to produce 2.1 megawatts of power for a thousand hours each year. Another key advantage to this plan is that since the "PowerTrains" are mobile, they can be taken to the areas that need power the most, so it doesn't have to be routed across the state through our power grid."
Diesel engines on trains are designed to do only one thing, produce electricity to drive DCtraction motors. They are actually portable power plants to begin with. This is a novel idea indeed
Do you even lift?
These aren't the 'roids you're looking for.
But this was done recently for electric power; in 1998, a disastrous ice storm destroyed a fair portion of the electric distribution system in Québec; in a suburb of Montréal, diesel locomotives were lent to the city to provide emergency power; they even ran the engines on the frozen street without any track at all!!! (other links here and here).
The use of a power generator, power transmission and motive force is a very old railway and marine tradition, indeed these are the building blocks of any useful engine. This is because when power sources become this big, axle and gearbox type transmissions become insanely huge in order to stand the massive amounts of tourque generated. This is of course ignoring the difficulty of distributing this tourque evenly over multiple drives.
Just take a look at old fashioned steam trains, you have a power generator consisting of a wood fired or diesel fired boiler, a transmission consisting of steam and a motive force consisting of pistons. Modern diesel-electrics have just substituded more modern elements. Don't be fooled into thinking that the conversion into electricity makes these engines inefficient, all transmissions including the transmission in your car incur a loss to the power outputted by an engine. (This is why car performance enthuisists measure power "at the wheel", not just at the engine).
For large engines, the conversion to electricity, steam, etc can actually be less than that of a gearbox style transmission, while allowing these engines to run at the constant rate that they are designed for. (Typical diesel electrics have difference between idle and redline of approx 50RPM (not a typo))
Smaller locomotives, such as that used and kids fairs etc, or theme parks, tend to use a diesel engine hooked up to a pump. This pump drives hydrulic fluid (typically brake fluid) over drive mechanisms that resemble minature water wheels. Speed can be controlled with the use of bypass valves. One that I looked at, was using an old toyota coaster diesel engine and a modified oil pump out of a larger (volvo?) truck. Coarse speed control was by throttling the engine, fine control or low speed via the bypass valve control.
URL of typical modern diesel-electric specs:
http://www.qroti.bit.net.au/fleet/2800.html
Base load power is always cheap (the steady stuff, like hydroelectric and nuclear), but any power above that is always a lot of money, since it's all about supply and demand.
I work in a nuclear power plant, and our cost per kilowatt is peanuts. But we cannot supply the whole province (I live in Ontario) with nuclear power alone. Cheap power like ours supply about 50% of the province. Outside of that, we have to run the expensive fossil fuel plants. And if we can't make 100% of the power needed, there's either going to be brown-outs, or we have to buy power from elsewhere. And that's where the MASSIVE energy costs are from. It is said that 90% of the cost of electricity is from that extra 10% needed that is brought in from elsewhere.
So if they can localize the production of power, without having to have it brought in from out of state, California stands to save quite a bit, even if it's just 100MW.
Diesel engines (and gas engines) have an optimum RPM, where they are the most efficient.
In something that is fuel/electric hybrid, you can use the fuel section at an optimal way to produce power, and then regulate the electric how you want.
Same thing goes on I think in like an M1 tank.. a gas turbine (jet) engine runs at constant speed producing power.
The State of California in 2001 produced 265059 Gigawatt-hours, or almost 3000 times more electric power than these trains are supposed to produce. Even solar energy contributes more to California; 638 GW-hours!
California Gross System Electricity Production for 2001
Taking stuff apart since 1969 (TM)
Hydraulic transmissions, which are variable-displacement pumps driving hydraulic motors, are sometimes used for low-speed switch engines, but there's a vibration problem with hydraulic transmissions that's kept them as slow-speed devices. (I once worked in a hydraulic R&D facility, which built, among other things, prototype locomotive transmissions.)
But electric motors can produce full torque at zero speed. So they're just what you need to start up a freight train. A variable-speed electrical drive in locomotive size was a problem for a long time. Until about 1950, all you could do is switch windings into various combinations of parallel and series. Later, ignitrons (the big mercury-vapor member of the gas-discharge triode tube family) were tried. It took a while for semiconductors to work up to handling megawatts. BART was the first railroad with semiconductor motor drives, and they burned out giant triacs regularly for years.
The latest generation of locomotives finally does it right - the motors are synchronous AC three-phase motors driven by variable-frequency inverters in a closed-loop system. This synchronizes all the motors on all the axles (the motors are down in the trucks, near the wheels), which provides synchronized all-wheel drive. Synching all the wheels nearly doubled drawbar pull (the locomotive spec that matters), and the limits of couplers have now been reached.
Despite this, using spare diesel engines to generate power is a basically dumb idea except in emergencies. The efficiency isn't that good and diesels pollute more than any of the other popular forms of power generation.
First of all, it's "Sacramento." If you're going to talk about it, spell it right. Second off, I don't know where you're getting the idea that electricity is cheap in Sacramento. My SMUD bill (yes, I live here. I'm 2 blocks from the Capitol building.) is most certainly not cheap. Have you noticed all of the idiot protesters outside that vote DOWN power plants? How about the Sierra Club? The "NIMBY" folks? Deregulation has ceased to exist. It's over.
Also, there have been quite a few power plants built. In fact, SMUD has one on McClellan Air Force Base that just opened up about a year ago. Where the hell did you get the idea that not a single new power plant has been built?
Insulated from the state problems.. hardly. I walk downtown every single day and see our state problems right in front of me. The politicians walk around and see the same exact problems. Whether they do anything about it is another story.
Second sentence from the article.. And who is muddying the conversation?