What are the hazards associated with heating and storing water?

By Martin Price (Gamos Ltd.).

In a quest to minimise the energy consumed in cooking food and heating water, we have had a number of proposals that suggest using the surplus energy from Solar Home Systems, or from Solar mini grids to ‘pre-heat’ water. The core idea has been that if the surplus midday energy was used to pre-heat and store water, the cooking processes could start with ‘hot’ water, and/or the heated water could be used for washing. While this idea perhaps has some merits from an energy point of view, it introduces some risks related to waterborne diseases and concentration of minerals.

This briefing note lays out the core risks, and we would encourage all applicants who are suggesting ‘pre-heating’ water to explicitly explain why their system will either not allow standing water, guarantee the water will be sufficiently boiled before drinking and not lead to boiling water multiple times.

The briefing note explains how:

  1. Boiling water removes many but not all waterborne pathogens

Boiling provides a sufficient level of water treatment to mitigate against a wide range of wate