By Werner Bergholz
Technology advances have reduced the price of simple, universal, scalable photovoltaics by as much as 75%
An estimated 1.2 billion people worldwide, including 550 million in Africa and 400 million in India, have no access to electricity. Most live in rural areas where the population is sparse and incomes are low, making it uneconomical to connect homes and businesses to a grid. Nor is it feasible to generate power locally with a diesel unit, owing to high fuel costs and the need for substantial initial investment.
A stable supply of affordable electricity is a prerequisite for economic development. In fact, the consequences for people living without electricity can be dire: they may be deprived of adequate health care, or be unable to store fresh food. But one solution, based on the local use of renewable energy, requires minimal initial investment and can be expanded over time.
This “boot-strap” approach is based on the use of photovoltaics – a simple, universal, and scalable technology that is easy to maintain. Typically, in the first stage of this process, consumers would use a renewable energy source such as LED lighting, selling any surplus until they save enough money to buy lamp oil (on which Africans spend around $20 billion annually).
The additional revenue might initially come from selling small electricity surpluses to local farmers to recharge their mobile phones (thereby allowing them to work out the optimal prices for their crops), or to help them irrigate farmland using small electric pumps.
This is a new opportunity. Until three or four years ago, photovoltaics were prohibitively expensive. But advances in the industry and over-production have reduced their price by as much as 75%. The cheapest system, generating two watts of power, can cost as little as $10-20 and be expanded to almost any level, depending on the size and number of photovoltaic (PV) modules and the size of the battery storage unit.
It is simple, too. A residential solar-power system consists of just three components: the PV modules, a battery storage unit, and a charge controller. Such a system can supply low-voltage DC electric power at five volts for mobile phones, and 12V for LED lighting, pumps for outdoor use, and electrical appliances such as computers and televisions.
When single-phase or three-phase 230V AC power is needed (say, to power larger machines), an inverter must be used. This makes sense only for systems that are larger than a kilowatt of peak power and that have sufficient battery capacity. Local systems in one building could be connected to local low-voltage DC or 230V AC grids to improve the security of supply.
One major challenge to the boot-strap approach is developing cheap and durable batteries. Many residential systems break down after 3-5 years when the battery dies, undermining confidence in the system among owners who assumed that they had a lifetime supply of energy.
But it is not a complicated process to demonstrate how to extend a battery’s life to as much as ten years. Indeed, getting the most out of a battery may require only that its owner fully charges it at least once every two weeks and never discharges it to less than 50% capacity.
In addition, our own research team is currently exploring ways to rejuvenate old solar or car batteries – without requiring any chemical treatment or disassembly – for re-use in a residential solar-power system.
Once such technologies have been perfected, we can turn our attention to developing a boot-strap business model. We believe that existing distribution, sales, and maintenance networks for other goods and services could be adapted to supply and provide customer support for solar-power systems as well.
For example, bicycle mechanics, who are plentiful in Africa and rural India, or small shop and kiosk owners could be trained to install and maintain these systems.
The combination of low-investment electricity generation for households and the ability to sell surpluses, scale up output, and access pre-existing distribution and maintenance networks bridges a crucial gap in the energy market. It is a simple idea that would allow millions of people in poor, rural areas worldwide to integrate their activities with the wider economy, accumulate capital, and improve their lives.
Werner Bergholz is Professor of Electrical Engineering at the School of Engineering & Science, Jacobs University, Bremen.