Water requirements
The environmental impact of energy . A few examples

Water and energy are intimately linked. Most of the water on earth (97%) is salty. It is found in oceans and seas. A small proportion (2.5%) is freshwater in the form of ice (pack ice, icebergs...) and only 0.5% is liquid freshwater, found mainly in aquifers, in the form of rain, in lakes, reservoirs and rivers Around 4 billion tonnes of freshwater are consumed every year, broken down as follows: 70% for agriculture, 22% for industry and 8% for domestic use.

A distinction is usually made between :

• blue" water, i.e. water from rivers, lakes, groundwater, etc....