Which energy source is formed when organic matter trapped underground without exposure to air or moisture?

Sådan fungerer det:

* Organic Matter: Over millions of years, plants and other organic matter accumulate in swampy areas or other environments with low oxygen.

* Burial and Pressure: As layers of sediment build up, the organic matter gets buried deeper and deeper, subjected to increasing pressure and heat.

* Transformation: Dette tryk og varme transformerer det organiske stof, ændrer det gradvist til tørv, lignit, bituminøst kul og til sidst anthracit - den mest modne form for kul.

* No Oxygen: The lack of oxygen is crucial. In the presence of oxygen, the organic matter would decompose and break down.

So, the absence of air and moisture allows the process of coal formation to occur.