BaudouinLabrique wrote:Gaston wrote:Un
article comments on a recent study by ADEME.
An interesting extract:
The electrolysis yield - allowing an electric current to decompose the water molecule into hydrogen and oxygen - is currently around 70%. The compression of this gas also consumes energy, and the recombination of the water molecule in the cell, to supply electricity again, is done with a yield of the order of 45%. The overall output of the chain, from primary electricity to returned useful electricity, is therefore in a range of 20 to 30% depending on the applications, the storage pressure considered, logistics diagrams, etc.
These figures are in accordance with what I had indicated (40% of output may if we recycle residual heat, then we reduce the loss to 5%)
The problem is that these figures absolutely do not confirm what you said, and no more the figures for the commercial enterprise ...
Even with L'Ademe's optimistic figures, the final return is 0,7x0,4x0,9 = 0,25, which is roughly half of what you tell us; still the figure of 0,7 for electrolysis is very overrated, in industrial it is difficult to exceed 0,5 ...
This is not surprising, moreover: the more the energy transformations are multiplied, the more the efficiency takes a hit. As for using hydrogen as an intermediate, it is really seeking the difficulty: this gas is difficult to handle, tends to pass through all the bodies it meets and has a very low volume thermal capacity, which means that compress it strongly to store it properly.
Even the smallest accumulator battery, even of rustic technology, has more interesting performance ...
But why should we strive to find systems wasting 3/4 of dearly acquired energy?
