Why do desalination processes require large amounts of energy?

Desalination processes require large amounts of energy primarily due to the need to overcome the strong ionic bonds in saltwater to separate the salt from the water. Techniques such as distillation and reverse osmosis involve heating water or applying high pressure, both of which consume significant energy.

A strong answer should directly address the approved learning objective to explain why desalination processes require large amounts of energy. This question belongs to Potable water within Using the Earth's resources and obtaining potable water, so the response should use that exact curriculum context rather than a generic statement. The answer is correct when it names the key idea, explains the link to desalination, and keeps the wording specific to AQA GCSE revision.