The solar energy is used by many people. It uses Sun.
The Hydro Energy is clean and renewable. It uses a water.
Conduction happens when the electricity moves place to place. For example, it is hot pot and the metal spoon. The hot pot is hot and the spoon is cold. If you let the spoon let in the hot pot for about few minutes, the spoon will get about hot as hot pot because of the conduction. So that is the one of the examples for conduction.
Convection is the circular motion that happens when warmer air or liquid. Which it will make faster moving particles. For example, the hot air balloon. The fire makes energy which means hot air. The hot air tries to go up and the heat traps on the balloon and cold air goes down. That is called Convection current.
Radiation is energy transmitted by waves or a stream of particles. For example, the microwave. When the microwave is fully heating up, it is really hot. You plug the microwave and put the foods in the microwave and it cooks. The electricity turns on the microwave and the microwave makes radiation and it makes microwave very hot.