Quantification of human and embodied energy of improved water provided by source and household interventions

This study quantifies and compares the total embodied energy of the water produced by eight interventions – four household-level and four water source-level – used in Mali, West Africa. Total embodied energy measures the energy required to produce, install, and operate an intervention that provides or treats water over its life. This includes energy embodied in materials and human energy expended by users. Human energy, often assumed to be negligible in these types of analyses, was quantified using physical activity ratios. Embodied energy of materials was determined using the best available national economic input/output-based models. The embodied energy of water boiled with fuelwood was determined to be more than two orders of magnitude larger than water produced by any other intervention. Other interventions producing water with the largest embodied energies were the solar pump, India Mark II handpump, and the clay ceramic filter, all of which had large material energy components. The interventions with the lowest embodied energies required minimal material inputs and larger human energy inputs to collect and transport water (i.e., the improved well, rope pump, biosand filter, and household chlorination.). Results suggest there is no clear relationship between total embodied energy and the scale of an intervention (i.e., household- or source-level). However, human energy, often assumed to contribute a negligible amount to total embodied energy, was shown to be significant to all eight interventions, contributing over 90% of total embodied energy for four interventions. When the human energy was disaggregated by traditional gender roles, women performed over 99% of the labor associated with seven of the eight interventions. This has significant implications for gender equality, and underscores the importance of human energy in understanding the social impacts of drinking water interventions.