Micro hydro

 Here is an interesting video from Just Have A Think, about very small hydro-electric facilities, delivering from 5 to 15 kW, with small environmental impacts.  The costings estimated are very low: EU 23/MWh, or US$27/MWh.  This is cheaper that wind and utility-scale solar.  The minimum fall needed is 1.5m, and the maximum 5.  You need 66 of these micro-hydro projects to produce 1 MW of electricity, but you could say the same about rooftop solar, but there is now 3 GW (3,000 MW) of rooftop solar capacity in Australia.  The more diversified the sources of electricity supply are, the greater the reliability and security of the grid.  They would be a useful revenue source for farmers and small town water suppliers. But the greatest benefit of these micro-generators will prolly be for the billion or so people who don't have access to electricity.