Editing Energy development (section)

== Classification of resources ==

{{further|World energy supply and consumption}}
{{see also|Energy industry|Energy planning|Energy policy}}

[[File:Basic Open System Model.gif|thumb|right|Open System Model (basics){{Clarify|date=October 2024}}]]

Energy resources may be classified as [[primary resources]], suitable for end use without conversion to another form, or [[secondary resources]], where the usable form of energy required substantial [[energy conversion|conversion]] from a primary source.  Examples of primary energy resources are [[wind power]], [[solar power]], wood fuel, fossil fuels such as coal, oil and natural gas, and uranium. Secondary resources are those such as electricity, [[hydrogen economy|hydrogen]], or other synthetic fuels.

Another important classification is based on the time required to regenerate an energy resource.  "[[Renewable resources]]" are those that recover their capacity in a time significant by human needs. Examples are hydroelectric power or wind power, when the natural phenomena that are the primary source of energy are ongoing and not depleted by human demands.  Non-renewable resources are those that are significantly depleted by human usage and that will not recover their potential significantly during human lifetimes. An example of a non-renewable energy source is coal, which does not form naturally at a rate that would support human use.