The basis of generating an electrical (DC) current is you have a magnet rotating/spinning within a cylinder that is wrapped in electrical coil. As long as you can find something external to make the magnet spin, you have a source of electrical current going through the coil/wire.
Easy irl hack if you ever find yourself in a real life zombie situation:
- Take a washing machine and remove the cylindrical drum.
- Wrap the drum in copper/electrical wire
- Put a magnet on an axle within the drum so that it can spin freely throughout the drum
- connect the axle to some paddles
- Place the "generator" next to a river so that the water flow hits the paddles, spinning the axle
The spinning of the axle will force the magnet to spin around the drum, the magnetic field will rotate about the drum creating an electric current through the wire. The same spinning motion is what makes wind turbines work and is the same process utilized within generators themselves
Smash calculators to harvest their solar voltaic cells to generate small amounts of power. Small on their own but can equate to something more in collective quantities.
Biodiesel can be made using plant oil or animal fat mixed with ethanol and a catalyst such as Sodium hydroxide...
- You can get Sodium hydroxide (lye) from soap, or making it the old fashioned way...
- You can get ethanol by distilling alcohol products and you can ferment fruits and vegetables with yeast, sugar and water in a sealed barrel to get alcohol
SOOO...
My suggestion is for renewable energy but the Biodiesel thing I mentioned would work handedly into an all out chemistry update which would have implications in other areas like farming (for fertilizers) and explosive making