Understanding long-term energy use in off-grid solar home systems in sub-Saharan Africa

TL;DR

This study analyzes long-term energy consumption patterns in off-grid solar systems in sub-Saharan Africa, revealing a consistent decline in usage over time across diverse household archetypes.

Contribution

It introduces a novel clustering of load profiles and uncovers long-term consumption decline, independent of economic hardship, using a large dataset of solar home systems.

Findings

Identified five distinct load profile archetypes.

Found a 33% average decrease in daily energy use after two years.

Observed consumption decline even among households without financial difficulties.

Abstract

Solar home systems provide low-cost electricity access for rural off-grid communities. As access to them increases, more long-term data becomes available on how these systems are used throughout their lifetime. This work analyses a dataset of 1,000 systems across sub-Saharan Africa. Dynamic time warping clustering was applied to the load demand data from the systems, identifying five distinct archetypal daily load profiles and their occurrence across the dataset. Temporal analysis reveals a general decline in daily energy consumption over time, with 77% of households reducing their usage compared to the start of ownership. On average, there is a 33% decrease in daily consumption by the end of the second year compared to the peak demand, which occurs on the 96th day. Combining the load demand analysis with payment data shows that this decrease in energy consumption is observed even in households that are not experiencing economic hardship, indicating there are reasons beyond financial constraints for decreasing energy use once energy access is obtained.