No abstract

Highly efficient direct current (DC) appliances have the potential to dramatically increase the affordability of off-grid solar power systems used for rural electrification in developing countries by reducing the size of the systems required. For example, the combined power requirement of a highly efficient color TV, four DC light emitting diode (LED) lamps, a mobile phone charger, and a radio is approximately 18 watts and can be supported by a small solar power system (at 27 watts peak, Wp). Price declines and efficiency advances in LED technology are already enabling rapidly increased use of small off-grid lighting systems in Africa and Asia. Similar progress is also possible for larger household-scale solar home systems that power appliances such as lights, TVs, fans, radios, and mobile phones. When super-efficient appliances are used, the total cost of solar home systems and their associated appliances can be reduced by as much as 50%. The results vary according to the appliances used with the system. These findings have critical relevance for efforts to provide modern energy services to the 1.2 billion people worldwide without access to the electrical grid and one billion more with unreliable access. However, policy and market support are needed to realize rapid adoption of super-efficient appliances.

The Lumina Project includes an Off-Grid Lighting Technology Assessment activity to provide manufacturers, resellers, program managers, and policymakers with information to help ensure the delivery of products that maximize consumer acceptance and the market success of off-grid lighting solutions for the developing world. Periodic Research Notes present new results in a timely fashion between the issuance of more formal and lengthy Technical Reports. Our results should not be construed as product endorsements by the authors. For a full archive of

No abstract

Summary The energy intensity of fuel‐based lighting is substantial given the paltry levels of lighting service, poor economic outcomes, and exposure to public health risks for users throughout the developing world. There is a great opportunity to reduce fossil energy consumption (and mitigate greenhouse gas emissions) while improving public health and economic outcomes for the poor by encouraging upgrading from fuel‐based to rechargeable light‐emitting diode (LED) lighting. However, switching to efficient lighting requires up‐front investments of energy for manufacturing. This study explores life cycle energy performance in the market for modern off‐grid lighting (OGL) products in Sub‐Saharan Africa and introduces a new metric, life cycle efficacy, which facilitates comparisons and analysis of life cycle energy performance (light output per unit of embodied plus use‐phase energy consumption) for lighting technology systems. Combining field insights on technology adoption dynamics with embodied energy estimates for a range of products available in 2012 shows that OGL energy “debts” are “paid back” in 20 to 50 days (substantially faster than kilowatt‐scale grid‐connected solar electricity systems) with energy return on investment ratios from 10 to 40. This stems from greatly improved life cycle efficacy for off‐grid LED lighting (∼20 lumens/watt [lm/W]), compared to fuel‐based lighting (∼0.04 lumens/W). Life cycle benefits—not only energy, but also economic and health benefits—depend strongly on product service lifetime (related to quality) and fuel displacement fraction (related to performance). OGL life cycle efficacy increases from longer lifetime and/or improved LED source efficacy lead to better quality and less‐expensive lighting available in the developing world with lower energy use than the fuel‐based incumbent technology.