energy sources that originated from biological materials

composed of hydrocarbons

A combustible black or brownish-black sedimentary rock

normally occurs in rock strata as layers or veins called coal beds or coal seams.

The process of coal formation 

What affects the rate of it and the quality of coal?

It all starts with a swamp on the edge of a sedimentary basin, such as a lagoon or a lake.

Plant debris accumulates and is buried under layers of mud and sand in a process known as

will happen for over a long period of time which will cover the plant debris and slow down the decomposition

is liquid fossil fuels

gaseous fossil fuels

The formation of oil and natural gas have a great similarity.

can only form in reservoir rock

may accumulate in large quantities in this porous, permeable rock

This heat comes from the decay of radioactive elements and the residual heat produced when the planet formed.

The rock reservoirs that contain groundwater

covers all techniques used to recover the heat in the Earth’s subsurface, particularly aquifers

This heat tends to increase as you go deeper to the ground.

Average value of gradient is  per 100 meters

Hot water from underground is pumped through a heat exchanger which heats a second liquid that transforms into steam.

Hot steam from underground is piped directly into turbines, which powers the generator.

Hot water from underground is pumped into a cooler temperature flash tank. The sudden change in temperature creates steam which powers the generator.

Almost 40% is generated by

The use of water to produce electricity

creates a large waterfall and stores enough water to supply the plant at all times.

channels water from the reservoir to the turbines

houses the turbines driven by the waterfall and the generator driven by the turbines.

Types of Hydropower Plants

Uses a dam to store water. Then, releases water to generate electricity

works by redirecting river water through a little dam into pipes towards a penstock and feeding it downhill to the power station.

combines a small storage reservoir with a system for cycling water back into the reservoir after it has been released through the turbine