Energy access through electricity storage: Insights from technology providers and market enablers
There has been a rapid increase in the deployment of solar home systems, nanogrids and microgrids coupled with electrical energy storage devices that enable off-grid access to energy and power stability. Developments in the electric vehicle industry have led to significant innovation in energy storage technologies, increasing cycle life at the same time as reducing costs. However, selection of rapidly developing energy storage technologies for remote deployment has been a question of great debate in terms of technology selection and optimisation for performance, lifetime and costs.
This study analyses outcomes from a series of interviews with organisations providing off-grid energy solutions. The interviews were focused on technology choice, challenges and opportunities. Key insights revolve around technology availability, real-world cost of storage solutions, performance of technologies and the environmental impact of storage technologies.
Figure – Deployed, growing and desired storage technologies in off-grid applications and technology characteristics. Sectorial perspective is based on interviews and reflects company views. Technology perspective reflects industry standard and interview insights.
1. Energy storage technologies vary in terms of cost, cycle life, charge / discharge rate and environmental impact. Different business models and applications favour different technologies.
2. Lead-acid (PbA) and lithium-ion (Li-ion) batteries are the dominant storage technologies in all but the largest systems. Lead-acid batteries are mature and costs are relatively stable, whereas Li-ion battery costs are falling rapidly. In addition, Li-ion batteries have higher cycle life, and can charge / discharge faster than PbA batteries.
3. Companies using PbA batteries may switch to Li-ion batteries within the next 5-10 years as Li-ion becomes more cost competitive. Generally, applications requiring batteries of lower energy capacity switch first, owing to lower capital required per product.
4. PbA and Li-ion batteries are expected to remain dominant for at least the next ten years, but, other, less mature storage technologies such as Redox Flow Batteries (RFBs) are beginning to be commercialised and could be promising in the future.
5. Amongst Li-ion battery chemistries, those with lithium-iron-phosphate (LFP) cathodes are favoured owing to their safety and high cycle life in off-grid applications, in addition to their availability at relatively low costs from manufacturers in China and absence of toxic cobalt. However, quality of cells varies between manufacturers, and higher cost offers no guarantee of higher quality.
6. Li-ion batteries with nickel-manganese-cobalt (NMC) anodes, favoured in electric vehicle (EV) applications due to higher power and energy densities, could also be promising, particularly as costs fall and performance improves due to the scale-up of the EV market. But safety of such Li-ion chemistries in off grid applications has been questioned.
7. Thermal storage technologies, including thermal batteries, could become increasingly important at higher levels of energy access – particularly for agricultural refrigeration.
1. There have been efforts to characterise the quality, cost and performance of different technology products in the off grid storage market, but greater quality and safety assurance, with the establishment of related standards, is required to enable appropriate, cost-effective and safe technology and product choice. This should extend to battery management and other battery electronics systems.
2. Measures to support the adoption of less mature technologies such as RFBs, which have been tested but not widely deployed, would help establish such technologies, enabling particular applications to benefit from their attributes.
3. Managing the environmental impact of storage technologies, particularly at end-of-life, represents a major gap. More detailed, effective and widespread regulation on end-of-life procedures, alongside supporting the emergence of a greater number of reputable, high quality and high safety recycling companies, would improve practice in this area.
Few, S., Schmidt, O., Gambhir, A., Stephenson, E. Access to Energy Storage: Insights from off-grid energy providers and market enablers. 2017. Grantham Institute & Shell Foundation. (Report)
Few, S., Schmidt, O. & Gambhir, A. Energy access through electricity storage: Insights from technology providers and market enablers. Energy Sustain. Dev. 48, 1–10 (2019). (Publication)
Schmidt, O. Rwanda - the cleantech silicon valley of Africa?. (Blog)