Average toilet flush is 5 litres which weighs about 5kg. The amount of potential energy depends on the height difference between the source and the turbine. If it’s right in the toilet you maybe have a meter of height, so you could potentially generate 5 kg * 9.81m/s^2 * 1 m = 49 Joules of energy from a single toilet flush. The average house uses about 1000kWH of energy every month, which is 3.6 billion joules. If you could capture the energy with 100% efficiency you would need about 73.5 million toilet flushes to recuperate the amount of energy for one household in a month. If each toilet is used 10 times a day you would need 7.35 million of these devices. If they cost $1 each this would be a $7.35 million dollar project. If a kWh is 25cents, the average monthly power bill for a house is roughly $250, which means in order to see a return on this investment in terms of energy costs these devices would have to work without maintenance for about 294 thousand years. You can gain more energy with a larger height difference, so if you used a turbine further downstream, say 100m down, it would generate more energy… For 100m it would take 2940 years. This is not factoring in the costs to build and ship these devices, and naturally such devices would probably cost more than a dollar and break down and they would also not recover 100% of the energy (maybe 30% if you’re lucky!)

What does fuck off with every minute possible option that creates energy mean ?

I'm not an engineer and don't understand how things work. You can create power but it's like Kinect energy. Maybe the flush of a toilet is more energy than you'd get from a turbine. You'd need to make sure nothing solid blocked the device. Would need to get everything tiny to fit and yeah would be miniscule power.

It's definitely doable but I think the output would just be lower than turning off a light or something.

I've no idea but someone will know.

I think something like a wind turbine in a car would be more useful. Just solar panels on a car would be useful. You might get 5/10 miles extra range. I think that's more useful than a fraction of a percentage from toilets.

Now rivers/ canals and waterways. That might give you enough power that it's worth it. Again maintenance would be an issue. Boats fish humans potentially. Maybe the odd shopping trolley and escooters