Electrochemical power sources:key agents for energy sustainability(Ⅱ)

3 Hydrogen distribution and storage3·1 Gaseous and liquid hydrogenIn the gaseous state,the most obvious method for distributinghydrogen would appear to be via pipeline·This has long been thepractice in Germany to supply hydrogen for chemical processes·…

Electrochemical power sources:key agents for energy sustainability(Ⅱ)

3 Hydrogen distribution and storage 3.1 Gaseous and liquid hydrogen In the gaseous state, the most obvious method for distributing hydrogen would appear to be via pipeline. This has long been the practice in Germany to supply hydrogen for chemical processes.More recently, other networks have been installed in Northern France, the USA, South Korea, and Thailand. The pipelining of hydrogen as a universal energy vector is a more difficult proposition since the distances would be much greater and the allowable costs much less. Apart from the huge capital investment that would be required, there are many technical difficulties, such as ( i ): materials problems (e. g., blistering, embrittlement and decarburization of metals) may not allow the use of natural-gas facilities; ( ii )the small molecular size of hydrogen renders it easily diffusible so that it could escape through existing natural-gas pipes (but mixtures similar to synthesis gas could be used in the interim); ( iii )the low volumetric energy density of hydrogen means that, to deliver a given amount of energy, the flow rate must be about three times greater than that for natural gas, and therefore more energy is required to move hydrogen; (iv) over long distances, there will also be a need to re-pressurize regularly, which will cause further loss of energy.