The humble solar home system, comprising in its simplest form a panel and battery, has helped millions of families in developing Asia gain access to electricity. In off-grid areas and poor communities, this setup provides a household with enough power for basic needs such as lighting, running a fan, or charging mobile phones.
Dozens of business models have been created to sell solar home systems to the poor at affordable rates, leading to millions of installed systems. ADB is working with private startups like India’s SELCO, whose strength lies in a doorstep service model, and close community ties. It has also partnered with Simpa Networks, which has introduced a pay-as-you-go system for financing solar home system purchases.
In the public sphere, ADB supports major initiatives like an off-grid solar program implemented by Bangladesh’s state-run Infrastructure Development Company Ltd., under which more than 4.1 million solar home systems have been installed across the country.
The next step is a larger scheme that generates sufficient energy for truly productive uses like powering local industries, refrigeration, and running water pumps or irrigation systems. Bringing that level of energy access to off-grid areas requires minigrid-scale energy infrastructure, at substantial cost. In contrast to the success of solar home systems, there has been no equivalent widespread success in the deployment of minigrids to help fill this need for larger sources of off-grid energy.
Linking solar-powered homes to waste less power
Now, ADB is partnering with SOLshare, a start-up in Bangladesh that seeks to leverage the vast installed base of solar home systems and upgrade them through so-called ‘swarm electrification’. The system operates similar to a swarm of bees, in that no central intelligence governs the network and a loss of power in one part of the system can be made up by the contributions of others. Also, the loss of any single panel does not undermine the ability of the rest of the ‘swarm’ of solar panels to function.
Instead of individual solar home systems working in isolation, SOLshare’s platform links them together in a peer-to-peer network to create a swarm for solar power production, thereby tapping into un-utilized power from excess solar energy produced by solar home systems. This power can be traded within the community, allowing households with surplus power to earn money by selling it to those families who would otherwise go without energy.
The idea is for neighbors to informally trade electricity with each other, especially to charge mobile phones. This setup is particularly suited to Bangladesh, where around 30% of the power produced by an average solar home system goes unused due to the standardized battery capacities sold alongside the systems.
An initial pilot in a central Bangladesh village has connected 8 households, among them one that before had no access to electricity but is now able to purchase the surplus from the neighbors. The trading credits are managed by mobile phones connected to bKash, the country’s largest mobile banking system.
Swarm is next step in off-grid solar
With ADB assistance, SOLshare plans to expand to 225 households as a first target. If the project can be scaled up there is a potential market of over 12 million people living in off-grid, unelectrified areas.
But challenges remain. Each device is relatively affordable, but very poor households with little or no access to credit need to take out loans to pay for one. Also, the network runs on low-voltage DC connections, which limits its overall scale and is only suitable for DC appliances. There are also the limitations of solar power, such as low energy production during the monsoon season from June to October, by the end of which a third of Bangladesh is under water.
A final climate-related risk is whether the swarm system can resist typhoons, which are becoming more frequent and intense as a result of climate change. If the swarm technology passes the test and continues to work when storms strike, then we should look into whether swarm resiliency can be adapted for use in other critical systems, such as telecommunications.
Hooking up rural communities to solar power can provide renewable energy access for the poor. Swarm technology may represent the next step in the evolution of off-grid solar, with houses that are physically separate but linked through basic infrastructure to meet their power needs.