Potential for use of solar-derived electrical power in the developing world is increasingly recognised. This report considers electrical energy storage systems for application when hybridised with solar electricity generation. Potential applications range from the localised low power uses that are already seeing initial introduction, to electrical energy storage to promote stability of electrical supply in neighbourhoods or slum areas, through to substantially higher power localised applications such as solar electric cooking.
Consideration of the state of the art in 2015 for introduction of new battery technologies into such contexts highlights the potential of the lithium iron phosphate (LiFP) battery type for such applications. The lithium titanate (LTO) battery type is already employed in transportation applications but has lower cell voltages and energy density which would necessitate a larger energy storage unit; LTO batteries have some perceived advantages in term of power density and cyclability and should also be considered.
The research question posed is ahead of the capability of current common lithium ion battery types to deliver long term, durable performance at high (tropical) temperatures, but arguably not by much in this rapidly advancing field. There can be optimism that lithium ion battery packs will shortly have evolved to a point where they could realistically be taken forward to possible high power applications in the developing world.
The report makes recommendations for implementation in the context of development of energy storage in higher power solar electricity systems with potential for deployment in the developing world:
- Recommendation 1: A programme of experimentation which should focus on full characterisation of the behaviour of LiFP battery packs (both current and shortly to be released), and (for meaningful comparisons relative to an existing alternative battery pack approach) of sealed lead acid (VRLA, valve regulated lead acid) battery packs, both with duty cycles appropriate to higher power delivery at elevated temperature, as in solar electric cooking in the developing world. LTO battery packs should also be considered provided the increased associated cost is not seen as a barrier. Safety testing under conditions of thermal abuse is necessary.
- Recommendation 2: A life-cycle-based techno-economic-ecological comparison of different energy storage options is also strongly recommended; specifications for the battery management system for such applications in “hot” countries can be developed from such a study. In addition the potential recycling of modern cell systems has to be investigated.
- Recommendation 3: Maintain a watching brief on future battery technology developments.
- Recommendation 4: Develop an interface between a prospective solar electric cooking development programme and battery pack manufacturers.
- Recommendation 5: Consider the potential for extending cycle life and useable electrical energy storage performance by incorporation of supercapacitor components when seeking persistent high electrical power output capabilities.
Lithium ion battery types, packs and arrays suited to solar electric cooking in the developing world appear technically possible, and the potential of the LiFP type is highlighted. There is, however, a current shortage of key, independent data for this particular type of use and duty cycle.
This report has been produced for Evidence on Demand with the assistance of the UK Department for International Development (DFID) contracted through the Climate, Environment, Infrastructure and Livelihoods Professional Evidence and Applied Knowledge Services (CEIL PEAKS) programme, jointly managed by DAI (which incorporates HTSPE Limited) and IMC Worldwide Limited.
Slade, R. Key assumptions and concepts on potential for solar electric cooking: Batteries capable of operating suitably in &#8216;harsh&#8217; conditions in the developing world. Evidence on Demand, UK (2015) iii + 19 pp. [DOI: 10.12774/eod_cr.november2015.slader]