Generate Power from water leaving your home
It occurs to me that a lot of power is supplied to pump water into my home -- into my showers, dishwasher, sinks, toilets, etc. And then, as that water plummets from the second story bathroom back into the ground, it builds up a lot of power due to gravity -- and it just goes whooshing away.
So let's develop some sort of mechanism that will harvest the energy of that moving water as it leaves our homes.
The initial thought is turbines or wheels, sure, but you have to remember the stuff that is leaving the house in that water: hair, food scraps, and all your bathroom functions.
So we need to either develop a system that cannot be jammed, filter & divert the water before it reaches our device, or develop a system that harvests the energy without interfering with the flow.