Hotspot is a region, where a molten rock is trapped. It is formed in the deeper hot regions of Earth’s crust, is pushes upwards through geological changes.

When underground water comes in contact with hotspot, a stream is generated. This steam trapped in turbines is routed through a pipe to a turbine and is used to generate electricity.

Sometimes hot water from that region also finds an outlet. It is known as hot springs.

Advantage: cost of production is not much

Disadvantage: there are very few such commercially viable sites, where energy can be exploited.