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---------------------- 2251 - Hydrogen trains before hydrogen cars.
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- The UK government cancelled its plans to electrify train lines because there may be a better alternative way to turn British railways electric: hydrogen.
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- Hydrogen trains have already replaced more polluting diesel engines on a line in Germany, and some train companies think the vehicles could be running in Britain as early as 2022.
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- A third of the UK rail network has been electrified. Without continuing to electrify the network, the government is faced with the dilemma of how to eliminate diesel trains that produce carbon dioxide and other harmful pollutants.
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- If electrifying the rest of the network is deemed too expensive, one potential alternative is to generate electricity on board the train instead of power in overhead lines.. One way to do this is to use fuel cells that combine hydrogen gas with oxygen from the air to produce electricity and water.
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- Hydrogen can carry more energy than the same weight of batteries, meaning fuel cell systems could be lighter. They also take less time to refuel than batteries take to recharge and don't have the same high environmental costs from manufacturing.
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- The hydrogen gas would need to be compressed into tanks that would usually be stored on the train's roof. By adding a regenerative braking system the train’s momentum could charge batteries that would reduce the amount of hydrogen needed to power the train.
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- The high cost of installing overhead wires means that hydrogen trains would likely be a more economic way to electrify railway lines with relatively low volumes of traffic. And it makes sense to experiment with hydrogen trains to uncover any unexpected issues.
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- One solution might be to develop bimodal trains that can switch between electricity from overhead wires and fuel cells. This would be especially suitable for the UK rail network, which has many bridges and tunnels that are too low to run overhead cables beneath and very expensive to replace. If electric trains could switch to hydrogen power for sections of track with bridges or tunnels rather than requiring cables, it could considerably reduce the cost of electrification.
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- The other problem with hydrogen fuel cells is that the fuel is currently manufactured from methane , or natural gas, using a process called steam methane reforming that also produces a large output of highly toxic carbon monoxide. This can be converted to carbon dioxide but that means using hydrogen fuel cells still contributes to greenhouse gas emissions.
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- A pollution-free way of producing hydrogen is through electrolysis, by passing an electric current through water. In theory, you could use excess wind power and solar to generate this electricity and make the hydrogen a renewable energy source.
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- The issue is that electrolysis plants are unlikely to be economic unless they run for a high proportion of the day. This would mean that when there wasn't excess wind to power them, they would need regular electricity from the grid that would make the process highly expensive and not necessarily renewable.
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- A second alternative is to use a "thermo chemical" production method that involves reacting water with sulfur and iodine in the presence of heat. The good news is that this method is set to become economical within the next ten years thanks to the development of generation IV nuclear power plants. These high-temperature, small modular nuclear reactors are being developed now in several countries
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- Despite the current limits of hydrogen as a transport fuel, as more and more countries undertake further research on the hydrogen economy, its costs will fall substantially, just as they have for solar and wind power. Hydrogen could even eventually come to replace natural gas.
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- The difficulty often seen in trying to introduce a new kind of transport fuel is that vehicle owners won't use it without the infrastructure to support it but infrastructure builders won't install it unless there is demand from vehicle owners. A government-funded experiment with hydrogen trains could help overcome this problem and bring the renewable hydrogen economy one step closer to reality
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- In January , 2019 , Germany rolled out the world's first hydrogen-powered train, signaling the start of a push to challenge polluting diesel trains with costlier but more eco-friendly technology.
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- Two trains began running a 62-mile route between the towns and cities in northern Germany, a stretch normally supported by diesel trains. Germany plans to deliver another 14 of the zero-emissions trains by 2021.
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- These hydrogen trains are equipped with fuel cells that produce electricity through a combination of hydrogen and oxygen, a process that leaves steam and water as the only emissions. Excess energy is stored in ion lithium batteries on board the train. The trains can run for around 600 miles on a single tank of hydrogen, similar to the range of diesel trains.
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- This new technology is a greener, quieter alternative to diesel on non-electrified railway lines that can help combat air pollution. Hydrogen trains may be in our future. Not just pollution but overcrowded highways in big cities may move the development even faster.
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- January 31, 2019
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