Explain why 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, which requires significant heat for distillation or high pressure for reverse osmosis. This energy consumption can make desalination costly and less sustainable.

A strong answer should directly address the approved learning objective to describe desalination as a method for obtaining potable water from salty water or sea water. 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 potable water, and keeps the wording specific to AQA GCSE revision.