Granville - water power

After we did the purple bike run, and before we visited a local garden, we trundled off to the seaside to find a random café for lunch.  On the way back we came across this enchanting (at least to me) water mill.

Three wheels, no less, and all fed overhead, the most efficient way.

I like water mills.   In these times where we're expected to change to renewable energy sources, here's one.  And it's efficient too, with a water mill returning, during its working life, about 200 times the energy used to build it.  (By comparison, solar panels, in these latitudes, return about two times)   What's not to like?

It puzzles me that here in France, in the Mayenne at least, the civil service seems determined to put as many water mills out of action as possible.   This results in a "change of use" of the building, that in turn means that the owner loses the right to use the water's energy.   I suspect that in a few years, the state will come back and take the rights, and re-create the mills, now as a monopoly supplier of energy.