One of the earliest ways to power mechanical engines was steam. Although it is not very efficient, many things will be burned after the collapse of human civilization. A steam engine can use heat to boil water and turn it into steam, and then the steam expands to push the piston or other mechanical components to move, thus generating electricity.
2. Internal combustion engine generator
Internal combustion engines are quite common in modern times. They use gasoline, propane, diesel or natural gas. They operate in the same way as car engines: a small explosion pushes the piston to move, which in turn makes the magnet generate electricity. The advantage of internal combustion generator is that it only needs to be started when electricity is needed. This is beneficial to prevent energy waste.
3. Wind energy
They are often called "hybrid systems" and combine solar energy, because wind energy and solar energy are intermittent. An interesting alternative is the Feng Shui complementary system, which uses wind energy to pump water to a high trough. When generating electricity, releasing water can generate kinetic energy.
4. Water energy
Humans have been using the power of rivers and streams for some time, such as building huge hydropower dams. Many of my companies are committed to building domestic water turbines that use rivers and streams, and some of the most efficient models are enough to supply power to medium-sized families. No matter what the weather conditions are, small turbines, pumps or water wheels can generate electricity 24 hours a day.
5. Solar energy
The sun may be the most reliable energy source, because its life span is several billion years longer than that of human beings. Most domestic solar energy systems do not store the excess energy they generate, but send it back to the main power grid. The power grid is gone, and batteries are needed to store it.
People's Network-Counting Seven Power Generation Methods after the End of the World