In organic chemistry, the cycloalkanes (also called naphthenes) are the monocyclic saturated hydrocarbons.

A phrase used to describe a technology that is at the forefront of design.

The cut-off voltage is the voltage at which a battery is considered fully discharged, beyond which further discharge could cause harm.

The wind speed at which a wind turbine ceases to generate electricity.

The wind speed at which a wind turbine begins to generate electricity

A method to reduce the amount of electricity that could have been generated but is curtailed due to less demand or to balance output.

A current source is an electronic circuit that delivers or absorbs an electric current which is independent of the voltage across it.

Electric current collectors are used by trolleybuses, trams, electric locomotives or EMUs to carry electrical power from overhead lines or electrical third rails to the electrical equipment of the vehicles.

An electrical device with jaws which open to allow clamping around an electrical conductor.

The curie is a non-SI unit of radioactivity originally defined in 1910.

Crystalline silicon is the dominant semiconducting material used in photovoltaic technology for the production of solar cells.

Use of liquification of air or nitrogen as an energy store.

Crude oil stabilisation is a partial distillation process that renders crude oil suitable for storage in atmospheric tanks, or of a quality suitable for sales or pipeline transportation.

A crude oil assay is the chemical evaluation of crude oil feedstocks by petroleum testing laboratories.

A naturally occurring oil found in the earth, crude oil is referred to as a non renewable energy source.

Used to protect a circuit from a surge or overvoltage condition

Crosswind kite power is power derived from a class of airborne wind-energy conversion systems or crosswind kite power systems characterized by a kite system that has energy-harvesting parts that fly transverse to the direction of the ambient wind.

A crosshead is a mechanism used as part of the slider-crank linkages of long reciprocating engines and reciprocating compressors to eliminate sideways pressure on the piston.

A criticality accident is an uncontrolled nuclear fission chain reaction. It is sometimes referred to as a critical excursion, critical power excursion, or divergent chain reaction.

A critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction.