The electricity we use is the same as the electricity generated by lightning. Usually when there are clouds in the sky, the water vapor gets so cold that it takes the shape of ice and collides with each other. This collision produces an electric charge. Above the cloud there is a positive charge and below it there is a negative charge. Since opposite charges attract each other, when these positive charges and negative charges come in contact with each other, they actually emit charges from top to bottom due to their potential difference. As a result, energy is released , sound is produced and light is produced.