I have used low pressure air and a simple "airlift pump"  to cycle water around a "pallet  Garden" since August.  This meant that very little water was being used but the plants were growing really well.   the air comes from an aquarium bubble pump and it is about 1 psi.  The pallet garden is almost 20 ft from the little bubble pump.   Recently I decided to do something similar in my greenhouse, but it is 120 ft from the little pump and there is no electrical socket close.  So reluctantly I bought another 120 ft of 1/4 inch tubing to send the air to the greenhouse.  I didn't expect it to work at that distance.  But it is working great. Why not use air instead of electricity to move the energy from "toy" windmills in gardens? Or from low head small water power?  I bet anyone could make a compressor to make 1 PSI.  It is orders of magnitude easier than making a direct water pump or converting the energy to electrical and then back again in a pump.  An airlift pump is just a vertical tube in the water.    How simple is that!   and it is darn cheap too.  You can use this for pumping water (Highest I ever got was 18 ft with 1 psi) or just bubbling air into a fishpond or to actually move the water in small water features.   Or of course in the pallet garden or in aquaponics.  And even thought this energy is useful at that scale it can never ever be made worthwhile to share it electrically.  But maybe your grid could extend to your neighbours garden too?  You could have an interconnector if you or they have a bit of excess pneumatic power!