Hydrogen could save regional railways

November 29, 2013
by Andreas Hoffrichter, The Conversation

Small, but not for long. Credit: niversity of Birmingham

There is increasing talk of electrification of the UK's railway network. But electrification is an expensive business, requiring much new hardware including masts, wiring, substations and so on. Such an investment can be justified for heavily used lines such as urban metro systems and inter-city routes, but not on less used lines such as regional routes. Railways will continue to need an energy supply system that does not rely on electrification for the foreseeable future.

This currently takes the form of diesel power. But in addition to environmental concerns over emissions, the price of diesel is likely to continue to increase. A point will be reached in the future where it is no longer economically viable or environmentally acceptable to use diesel, and hydrogen appears to be an attractive alternative.

Like electricity, hydrogen can be produced from many different primary sources including natural gas, coal and petroleum. It can also be produced using electricity to split water into its elements. Then there are several "green" production options being developed including the anaerobic digestion of waste material and the direct use of heat from solar energy. But unlike electricity, hydrogen can be stored and transported in discrete quantities in order to power trains, much like diesel or natural gas.

To release the energy stored in the hydrogen, one option is to use a fuel cell. In this device, hydrogen is combined with oxygen from the air to produce electricity, water and heat. There are no harmful emissions or exhaust fumes, and the technology is quiet, vibration-free and low maintenance – all attractive features for railway applications. Fuel cells are usually combined with batteries which help meet the peak power demand during hard acceleration, and to provide a store for energy recovered during braking.

A recent study by the University of Birmingham showed it is possible to store enough hydrogen onboard a modern train (a lightweight commuter train in this case) to provide a similar range to diesel power. In contrast to battery only systems, re-fuelling takes a similar amount of time to diesel, and only a limited number of re-fuelling points would need to be provided. Commercially, the cost of hydrogen is comparable to that for diesel, and the inherent ability of a hybrid system to store and reuse braking energy helps reduce overall consumption.

To show the viability of the technology, the UK's first hydrogen-powered locomotive, called the Hydrogen Pioneer, was developed and built using off-the-shelf technology. The locomotive uses a 1.1kW fuel-cell stack to charge four lead-acid batteries that provide the combined power for acceleration and store energy when braking. The 320kg-locomotive can haul wagons and passengers up to 4,000kg.

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Elsewhere in the world, hydrogen-powered railway vehicles have been constructed in Spain, the United States, China, and Japan. These have mostly been prototypes, but the first commercial operation of hydrogen power has been for mining locomotives, with a fleet now operating at a platinum mine in South Africa. In 2014, hydrogen-powered trams will start commercial operation in Aruba, with hydrogen generated solely from renewable sources.

It is possible that hydrogen-powered trains will see service on the UK network within the next few years, most likely on lower-speed applications such as trams or shunting locomotives. But hydrogen has the potential to play a larger role, powering those parts of the network where electrification does not make sense.

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16 comments

"But in addition to environmental concerns over emissions, the price of diesel is likely to continue to increase."

"Like electricity, hydrogen can be produced from many different primary sources including natural gas, coal and petroleum."

How do people with no knowledge of physics or energy conversion get published?

Prove to me that converting natural gas into H2 can be more cost, pollution and energy efficient than burning it directly in an engine. How can green science deserve any respect at all when it is represented by articles like this???

Prove to me that converting natural gas into H2 can be more cost, pollution and energy efficient than burning it directly in an engine.

Since they're not claiming it does - why should they need to prove it?

Even so I could see that sometimes there are considerations about global vs. local pollution. E.g. for trains operating largely within population centers it is sometimes better that they don't pollute locally - even if the combined global pollution by producing their fuel elsewhere is greater.

Local railroads need to plan economically with a long time horizon. The price of diesel can only go up, making such plans dicey (and quickly push them into the 'uneconomical' region).

With the amount of income of people using railroads stagnating/dropping they cannot hope to match this price increase with increased revenue in the long run. railroad owners need a fuel that will remain stable in price (or become cheaper as technology develops). Hydrogen could just be that fuel.

"Since they're not claiming it does - why should they need to prove it?" So if they are not claiming that converting viable fuels into hydrogen has any advantages at all, what exactly is the point of the article? Natural Gas is a superb fuel and converting it to H2 for transportation use is just plain stupid.

"railroad owners need a fuel that will remain stable in price (or become cheaper as technology develops). Hydrogen could just be that fuel."

There is absolutely no proof that H2 derived from fossil fuels could ever be more efficient than using the fuel directly.

There is absolutely no proof that H2 derived from fossil fuels could ever be more efficient than using the fuel directly.

The hydrogen from fossil fuels idea is debunked immediately by pointing out that methane (natural gas) can be used directly in a solid oxide fuel cell without conversion to hydrogen, because such fuel cells are internally reforming. They can even burn gasified diesel as long as there's no sulfur in it.

The output is just water and CO2 - no particulate matter or NOx or HCs - so AA's complaint about pollution and air quality doesn't apply.

The requirement for raw hydrogen is only a limitation of PEM fuel cells which pass the hydrogen ion through the membrane, whereas the SOFC works the opposite way by passing oxygen ions to burn whatever it is on the other side.

And methane stores twice the energy at half the pressure in a volume compared to hydrogen.

Like electricity, hydrogen can be produced from many different primary sources including natural gas, coal and petroleum. It can also be produced using electricity to split water into its elements.

All that applies to methane as well.

Then there are several "green" production options being developed including the anaerobic digestion of waste material

Anaerobic digestion of waste into methane is 99% efficient, into hydrogen just 5-10% efficient. The hydrogen digestion also releases byproduct organic solvents into the water, which actually makes it more polluted.

I too have troubles understanding what's the big deal with hydrogen? It's inferior to just about every other option you can imagine in almost every way imaginable. It takes the most space, it's the most flammable, it's the most difficult to contain, most expensive to obtain...

Look Anti, I read the article and unless there is an energy, pollution, and cost, effective way to produce H2 the whole article is a pipe dream.

Which is easily answered because you always have to ask yourself: cost effective compared to what?

If that which you compare it to (fossil fuels) is a finite resource then you have your answer. A finite resource can only become more expensive with time as it gets used up. Hydrogen is a (virtually) infinite resource so its cost is constant or will only drop with better technology. In such a setup there MUST come a point where it's cost effective.

If you look at the mounting cost due to environmental changes caused by fossil fuels (not to speak of the health costs) then that point has already long been passed. We're currently just deluding ourselves by kicking that particular can down the road.

People are still buying the hydrogen economy crap? Really? Let's see ... difficult to produce, difficult to transport and store, easy to use. Well, it has 1 of 3 worked out. Too bad the other two turn every corner fuel stop into a bomb just waiting for idiots to arrive.

"Hydrogen is a (virtually) infinite resource so its cost is constant or will only drop with better technology. In such a setup there MUST come a point where it's cost effective."

Look this article is about converting perfectly good fossil fuels into H2 which is a ludicrous use of precious resources.

If man ever develops a viable source of cheap renewable energy H2 could become a useful general purpose fuel after the containment and distribution issues are solved. As another poster pointed out, methane probably makes more sense as a fuel.

Look this article is about converting perfectly good fossil fuels into H2

No it is not. That is only mentioned because it is a possibility among many - for completeness sake.

Nowhere in the article does it say that this is the only or preferred way to do it. The article does not express a preference at all, but expressly stresses that there are green ways to do it. So if you want to interpret anything at all then they are preferring that.

Hydrogen is a (virtually) infinite resource so its cost is constant or will only drop with better technology. In such a setup there MUST come a point where it's cost effective.

No it isn't. Hydrogen isn't a resource since all of it has to be made. There's no hydrogen mines or hydrogen wells that spout infinite amounts of hydrogen - all of it has to be manufactured using -other resources-

What you're claiming is pure nonsense. It's like saying size AA alkaline batteries are a resource and it's just a matter of time before they become cost effective to drive your car on.

Of course with infinite resources we could make AA batteries, or hydrogen, so cheap to use that you could load your trunk full and drive into the sunset, but the point is that it would still be just a massive waste of effort.

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