solar and other alternative energies for railroads

[RedLantern]

Passenger cars could potentially have all of their Hotel power run off a rooftop mounted panel (thin film or otherwise), using LEDs for all lighting on the entire car, and low voltage heating and cooling using a seperate water heating solar panel and could provide heat and hot water. If the panel could put out enough heat, it might even be able to run an evaporative cooling system for air conditioning.

I do also like the idea of solar powered motive power, since there's so many ways it could work. One idea I had was small solar panels mounted on each catenary mast on an electrified line. With all the panels wired together in paralell, the power from any panels that are generating within a certain block (about a mile or so between mini substations). When a train is not in the area, the power can be transmitted along power lines to other areas where trains create more of a demand.

Using the same kind of idea using the combined power of all working panels, I also had an idea where the rooftops of freight cars could have solar panels installed, and the power is run through cables between the cars running the length of the set of cars set up for this. The power could then be stored in a battery and used to charge up a capacitor to give the traction motors an extra kick over hills or when speeding up.

The railroads could also offer special incentives for private freight car owners who install panels on their cars as well. As long as the AAR has some kind of standard for all cars set up this way, you could end up with 200 car trains where every car has a solar panel, and all that power is being fed into the traction motors.

This could potentially also work with intermodal containers, with panels recessed into the roofs of the containers. When the containers are on a train (single stacked, or on top of double stacks). with the containers connected to cables running the lengths of intermodal unit trains. Each car would have a system that logs how much time the top of the container was exposed to the sunlight (as opposed to being inside a cargo ship, stacked on top of, or on the bottom of a wellcar), and the railroad could deduct a portion from the shipment fee of that container based on the amount of time that container spent generating power for the railroad.

Theoretically, with current panels, the roofs of boxcars or covered hoppers should be able to hold enough panel space that with a few of these cars linked together, the motors would be using enough power to be able to throttle down the diesel loc's, or possibly even run at idle.

[David Benton]

a square metre solar panel generates aprrox 125 peak watts in full sun . to power a 3kw locomotive youd need 24 000 of them . at around $ 7 a watt , that would be $ 21 million worth . not quite there yet , though your ideas are on the right track .

[george matthews]

Passenger cars could potentially have all of their Hotel power run off a rooftop mounted panel (thin film or otherwise), using LEDs for all lighting on the entire car, and low voltage heating and cooling using a seperate water heating solar panel and could provide heat and hot water. If the panel could put out enough heat, it might even be able to run an evaporative cooling system for air conditioning.

Sorry, I actually know about photovoltaics.
I suggest you look for Home Power magazine which can give you practical details about the cost of PV power, and lots of information about people who have used it.
Try this page http://www.angelfire.com/mac/egmatthews ... ction.html

[lpetrich]

Interesting thread.

Hydrogen has a certain downside: it's hard to liquefy. Its boiling point at 1 atm pressure is 20 K, and its critical point is 33 K at 13 atm. So liquid hydrogen would have to be carried in a big cryogenic tank. And pressurized hydrogen would have to be carried in a big pressure tank.

But railfans may rejoice in the fact that locomotives are the most feasible land vehicles for liquid-hydrogen fueling, because of their size. Thermal insulation and pressure containment require an amount of material proportional to the tank's area, which increases as (size)^2, while the tank's volume increases as (size)^3. The economics of fuel-tank construction thus favors larger ones.

Liquid hydrogen has a density of 0.071 g/cm^3 (water is 1), and gaseous hydrogen at Standard Temperature and Pressure (0 C, 1 atm) has a density of 9*10^-5 g/cm^3. With the Ideal Gas Law, it's easy to scale it to some other temperature and pressure. Combining with water yields an energy output of 120 mJ/kg (steam) or 142 mJ/kg (liquid water) relative to the original hydrogen.

This gives a hydrogen available-energy density of 8.5 mJ/L of liquid hydrogen or 0.01 mJ/L of gaseous hydrogen at STP (100 atm of pressure yields 1 mJ/L, etc).

By comparison, typical diesel fuel is 46.2 mJ/kg by fuel mass or 37.3 mJ/L by fuel volume; other hydrocarbon mixtures like gasoline, kerosene, and crude oil are close to these values. So hydrogen would require bigger fuel tanks than diesel fuel for the same amount of energy.

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One extracts the energy by combining it with oxygen from the air, and one can do that either by burning it or by using a fuel cell. For burning it, one would likely use an internal combustion engine, since such an engine is more efficient than a steam engine. Existing diesel engines are designed for fuels that are liquid at room temperature, and they would have to be modified for using hydrogen, but the modifications are similar to the modifications for natural-gas-powered vehicles (natural gas = methane). Fuel cells are more efficient than internal combustion engines, and they produce zero nitrogen oxides, but they continue to be more expensive.

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Turning to sunlight, I will now consider how much area will be needed to capture it and substitute for a typical locomotive diesel engine. A common power rating is 3000 hp, or about 2240 kW (1 hp = 746 watts).

The amount that reaches the Earth is 1.37 kW/m^2, meaning that a minimum of 1600 m^2 will be needed to match that locomotive's power rating. This assumes 100% efficiency, and 50% or 25% efficiency would multiply that figure by 2 or 4, yielding 3200 or 6400 m^2.

We can use a typical 40-ft shipping container to estimate how much area a train will present to the Sun. It has dimensions length = 40ft, width = 8ft, height = 8.5ft, yielding an area of about 30 m^2 to present to the Sun. This means 55 containers for 100% efficiency, 110 for 50% efficiency, and 220 for 25% efficiency.

Thus, directly powering a train with solar energy would be impractical.

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Sources: Wikipedia (hydrogen, liquid hydrogen, energy density, sunlight, containerization), NIST's chemistry data

[george matthews]

So liquid hydrogen would have to be carried in a big cryogenic tank. And pressurized hydrogen would have to be carried in a big pressure tank.

Actually, not necessarily. There is an alternative. Metal hydride storage is possible, though at present expensive. It works at room temperature and is entirely safe from explosion.

In Europe I think hydrogen will come from Iceland, and possibly Norway, and Mediterranean sun. The Sahara is a great resource if we can cooperate with the inhabitants. For the US I suggest they get to work with OTEC and help reduce the hurricane intensity.

I think if we start realising that alternatives to oil are urgently necessary we could achieve a lot quite quickly. I think an Obama presidency will see an end to denial, which will be a great relief. I don't think McCain understands the problem, and Palin of course is a denialist.

My experience with renewable energy is that the main cost is capital, and that the higher cost makes one a fanatic at doing what is needed as economically as possible. Thus super-efficient refrigerators, LEDs for lighting (I don't have any being stuck in the compact fluorescent stage), insulation. For rail use in the US you need to do something about the weight of trains and get it down to French TGV standards.

Home Power is always full of information about how to use energy parsimoniously.

[lpetrich]

Metal-hydride storage looks like it won't need very low temperatures or very high pressures, but it has problems of its own. According to Wikipedia's article on hydrogen storage, metal hydrides typically have 3 times the volume and 4 times the weight of some gasoline with the same amount of available energy. And metal hydrides have to be heated in order to accept or release hydrogen.

[george matthews]

Metal-hydride storage looks like it won't need very low temperatures or very high pressures, but it has problems of its own. According to Wikipedia's article on hydrogen storage, metal hydrides typically have 3 times the volume and 4 times the weight of some gasoline with the same amount of available energy. And metal hydrides have to be heated in order to accept or release hydrogen.

Yes, we had better get on with serious research. The Bush regime closed down much of the necessary research. I hope the Chinese didn't close their programmes.

[David Benton]

A couple of new storage options are showing promise.
Lithuim air battery has a similar energy density to gasoline , without the explosive potential of Lithuiim Ion.
Lead carbon battery , while not solving the weight penalty of lead, offers longer life and deeper discharge cycle capability thn trafitional lead acid batteries.

[george matthews]

A couple of new storage options are showing promise.
Lithium air battery has a similar energy density to gasoline , without the explosive potential of Lithium Ion.
Lead carbon battery , while not solving the weight penalty of lead, offers longer life and deeper discharge cycle capability thn trafitional lead acid batteries.

Yes, I don't think we have nearly done all the work on energy storage that is possible. In the past, relying on cheap oil products has discouraged research into renewable alternatives. (During the Trump period, we shouldn't rely on any useful research or policy in the US, but he will pass - perhaps unexpectedly soon.) Maybe a successor will be more interested in preventing the emissions of CO2 to the atmosphere. But China and Japan are more active. The US will probably have to import these non-carbon technologies.

But for most rail uses I think installation of Overhead will continue to be the best method of electrifying and replacing oil products. It is only road and air transport that have the real problem of getting out of oil products.

[David Benton]

I think the battery options would be most suited for urban railways, where the overhead catenary is likely to be seen as visual pollution. Be it Tramlines , light rail , or perhaps heavy rail.

Another battery type I have recently googled is Nickel zinc , already in production(though the examples i have seen for sale don't measure up to the promise), Promising a better power to weight ratio.
https://en.wikipedia.org/wiki/Nickel%E2 ... nc_battery" onclick="window.open(this.href);return false;

[george matthews]

I think the battery options would be most suited for urban railways, where the overhead catenary is likely to be seen as visual pollution. Be it Tramlines , light rail , or perhaps heavy rail.

Another battery type I have recently googled is Nickel zinc , already in production(though the examples i have seen for sale don't measure up to the promise), Promising a better power to weight ratio.
https://en.wikipedia.org/wiki/Nickel%E2 ... nc_battery" onclick="window.open(this.href);return false;

My experience with batteries makes me reluctant to advocate them for a large scale. I have a battery operated hedge cutter - very useful for cutting lots of hedges. But the batteries don't last all that long. After a few years they no longer store electricity and there is no means of replacing them. We need to recognise that various chemical processes lead to most batteries running down like this and therefore the system needs to include a means to reformulate them every so often. Very large scale batteries for such uses as powering trains would have the same problem. Overhead - or third rail - would continue to be the best means of supplying energy. As the climate situation develops, rail use is likely to increase so conventional power supplies will continue to be appropriate methods. We are going to need considerable restriction of CO2 emissions. That is likely to make road transport more expensive and favour competing transport with electric connections. I don't think we should expect batteries to be a large means of storing energy for large uses.