By Paul Homewood

The Times reports:

Britain’s railways are to enter a new steam age with up to 100 ageing commuter trains poised to be converted to run on eco-friendly hydrogen. They could be on the network within three years and will be almost silent, with the same range and speed as traditional diesel and electric trains.

Their only emissions will be water, with some released as small puffs of steam above the train. The conversion programme — drawn up by Alstom, the French train maker — would make Britain a world leader in hydrogen train technology. Jo Johnson, the rail minister, called in February for all Britain’s 3900 diesel trains to be scrapped by 2040.

https://www.thetimes.co.uk/article/hydrogen-fuel-cell-trains-herald-new-steam-age-mdf78f2dk

There is no mention of where the hydrogen itself will come from, but the choice is between the steam reforming process, which uses fossil fuels and produces emissions of CO2 anyway, and electrolysis, which traditionally has been very small scale and expensive.

I came across this useful analysis, which helps to explain:

Hydrogen is not an energy source, but is an energy vector or carrier. This means that it has to be produced from one of the primary energy sources: fossil fuels, nuclear, solar, wind, biomass, hydro, geothermal and urban waste resources. All the energy we use, including hydrogen, must be produced from one of these three primary energy resources.

On earth, hydrogen is found combined with other elements. For example, in water, hydrogen is combined with oxygen. In fossil fuels, it is combined with carbon as in petroleum, natural gas or coal. The challenge is to separate hydrogen from other naturally occurring compounds in an efficient and economic manner. See the "Hydrogen Production Paths" chart below for unique ways to produce hydrogen from the three sources.

There are several methods for producing or extracting hydrogen. Steam reforming is a well-established technology that allows hydrogen production from hydrocarbons and water. Steam-methane reformation currently produces about 95 percent of the hydrogen used in the United States.

Another conventional technique is electrolysis, which applies electrical current to decompose water into hydrogen and oxygen molecules. The electricity for electrolysis can come from any of the three energy sources.

The cost of hydrogen production is an important issue. Hydrogen produced by steam reformation costs approximately three times the cost of natural gas per unit of energy produced. This means that if natural gas costs $6/million BTU, then hydrogen will be $18/million BTU. Also, producing hydrogen from electrolysis with electricity at 5 cents/kWh will cost $28/million BTU — slightly less than two times the cost of hydrogen from natural gas. Note that the cost of hydrogen production from electricity is a linear function of electricity costs, so electricity at 10 cents/kWh means that hydrogen will cost $56/million BTU.

http://www.fsec.ucf.edu/en/consumer/hydrogen/basics/production.htm

As is stated, the cost of producing hydrogen is directly linked either to the cost of fossil fuels, or the price of electricity.

Intrinsically then, hydrogen produced by steam reforming will always cost much more than natural gas, due to the processing involved. And there is nothing to suggest that electrolysis will suddenly become a cheaper, bulk scale alternative.

via NOT A LOT OF PEOPLE KNOW THAT

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June 9, 2018 at 05:33AM