Year/Course: 2014-2015, Easter 2015

Contact: Dr. R Vasant Kumar, Department of Materials Science
Mentor: Dr. Carlos Ludlow, EnVal Ltd.

For over 1.2 billion people, the main electricity grid is unlikely to be available in the foreseeable future. Instead they must rely on innovative combinations of top-down and bottom-up solutions to generate power. Regions commonly located in poor rural areas in Africa, Asia and Latin America that are deprived of electricity also show the lowest level of human development. It is anticipated that solar energy will contribute more than 10% of the energy mix in developing countries by 2022, driven by the goal of providing electricity to the hundreds of millions of off-grid rural people. There is a great opportunity to skip over polluting forms of energy and move straight to cleaner sources such as solar power. Leapfrogging in this way will avoid the large costs in transmission lines while benefitting the environment and the health of the people. Off-grid electrification is an innovation activity that should be harnessed for entrepreneurship and gainful employment.

Typically, electrical energy from a solar panel will be stored in batteries, so that stored energy is available without interruption over a number of days. Lead-acid batteries are already used in some rural off-grid electrification schemes for storing energy during peak energy production from photovoltaic modules. Lead-acid batteries provide the most economical electrical storage technology. These can be charged and discharged over a number of cycles (hundreds or even thousands) after which they become redundant. Given that discharge of lead into the environment is not an option due to toxicity they must be recovered and recycled back into making new batteries.

In developed economies recycling of lead batteries is based on heavy investment in large high-temperature furnaces backed by environmental control of dust, water and gases that are discharged. Such relatively expensive and large scale technologies are currently out of the practical realm of the rural sector. There is a thriving (often poorly regulated or even unauthorised) rural sector based on small scale units operating driven by the lucrative resale value of lead. The small scale units are not suitable to melt some of the difficult lead compounds in the spent batteries and thus do not robustly recover all the lead. Anecdotal evidence suggests that the unrecovered lead compounds are discharged into the local environment in the rural and the semi-urban space imposing a massive potential health burden. With growth in rural off-grid electrification via solar energy, the demand for back-up storage batteries will be intensified. Any opportunity to expand the rural sector infrastructure to handle the spent batteries in a safe way will greatly benefit the local population by expanding skilled employment opportunities and entrepreneurship.

A new technology for safely recovering lead from batteries in small scale units that will fit this requirement has been recently developed at University of Cambridge, precisely in anticipation of growth of battery usage spurred by rural electrification by renewables. Economy of scale is not a limiting factor, with this new technology, thus will offer options for catalysing a lead battery rural industry in rapidly growing economies. The method uses bio-energy in the recovery process thus the carbon footprint is low.

The question for the i-Team is to look at the realities of using the new recycling technology in the developing world, and to assess how this can best be taken forward.