In January 2016, SolarAid adopted the Global Off-Grid Lighting Association (GOGLA) ‘Standardised Impact Metrics for the Off-Grid Energy Sector’. Aligning to a harmonised industry standard for measuring and reporting on social impact within the energy sector will ensure consistent and reliable impact results, as well as the opportunity to strengthen the work of the sector as a whole through aggregating impact and showcasing the difference access to energy makes to a person’s life.
Solar light manufacturers state the lifespan of a solar light is up to 5 years, sometimes longer for larger more expensive products. Because this is a difficult indicator to measure, and even the World Bank and IFC’s Lighting Global Technical and Quality Assurance tests do not track this, the GOGLA metrics ensure that we are being more cautious about product lifetime in rural Africa and not over-claiming impact. Therefore, we calculate the lifespan at 150% of the warranty period. This results in an average lifespan of 3 years for the solar lights we sell.
Through using the GOGLA metrics we also include a discount ratio of 3% for solar lights that may be broken or not in use and we include a discount rate of 10% for repeated sales when required. Additional solar lights being used in homes which already have solar will still impact the household, but possibly not to the same extent, and of course we don’t want to double count people reached.
However, the standardised GOGLA metrics calculate a cross continent average household size of 5 people. Our own extensive research indicates a slightly higher household size of 6.2 averaged out over the countries we operate in. As we have sold lights in Tanzania, Uganda, Malawi, Zambia and Kenya exclusively we have taken the decision to use our own research data, rather than the pan African GOGLA data. Using this as the basis for the calculation, we are able to calculate that there are around 10 million people currently accessing our solar lights. If we were to use the GOGLA metrics, we would calculate that around 6.6 million people are currently accessing our solar lights. We feel that our own data provides a more accurate reflection.