Time for a rethink: How to max the humble mini-grid

What’s in the pipeline for climate ideas? We’re continuing our occasional series of innovation spotlights.

• For Africa to have a thriving green economy able to absorb substantial new investment, new ideas must lead the way.

The focus: Today, we’re looking at how African mini-grids can benefit from ambitious thinking. This is based on work done by CrossBoundary’s Mini-grid Innovation Lab.

• For a profile the lab’s leader, see the next story below

A. Second-life batteries: Castoffs from the Global North power many African markets. Take cars and clothes. Most are sold used. What might that look like for power units?

• After three years, many batteries are no longer efficient enough for electric vehicles but can still be used in stationary situations.

• Second-life power units from cars could be integrated into mini-grids; that may reduce unit cost by up to 40%.

• This becomes more attractive as the e-mobility sector grows, boosting the supply of used batteries.

• The capacities and maintenance needs of used batteries are not yet fully understood. Two South African companies, Blue Volt and Revov, are testing refurbishment and management systems for mini-grids.

B. Modular mini-grids: Scaling de-centralised systems as use grows over time is hard. Expansions are rarely seamless. Hence, most mini-grids are overbuilt and under-utilised (30%-40%). Capital is locked up needlessly. How to fix this?

• Studer is working on a smart inverter that makes it possible to add batteries of different ages to a single system. One can then expand over varying distances.

• OKRA has developed mesh grids for 4-5 households (software balances loads). Mesh grids sit in between solar home systems and mini-grids. They can connect users at the periphery of mini-grids, which is otherwise too costly.

C. Sub-metering: Perhaps not all power uses should be charged equally. Tariffs differentiated within an account would make it possible to subsidise climate-friendly uses. Current meters don’t allow this.

• PowerPay is developing a chip that makes it possible to track consumption at the appliance level.

• Developers could offer competitive tariffs on different usages. Watching TV? Pay the full rate. Switching from charcoal or gas to an electric cooker? Pay less for the power used.

• Industrial applications are also under consideration. An example: Reducing the cost of power for a grain mill when switching from diesel to electricity.