Complex sentence: Regarding electricity, which he pointed out was not an energy source but a means of energy distribution, Jevons noted that hydroelectric power was feasible but that reservoirs would face the problem of silt build-up.
Split into simpler sentences: Regarding electricity, which he pointed out was not an energy source but a means of energy distribution, Jevons noted that generation from from water held in reservoirs, i.e, hydroelectric power, was possible. But he pointed out that reservoirs would face the problem of silt build-up.