How is energy manufactured?

Right now, coal and nuclear plants are the main sources of power. There are currently many efforts to shift this to renewable energy sources such as geothermal energy, solar energy, etc.

The main reason for why renewable energy sources are currently not the main source is because their output cannot be adjusted during peak hours or other times of higher demand. In many cases, renewable energy plants are more expensive to operate as well. As for non-renewable energy sources, coal and nuclear plants can simply adjust their output during peak hours. The wind may die down or a storm may block the sun during peak hours, reducing the effectiveness of renewable power.