The innovators: how tiny amounts of wind energy could light up Africa
Royal College of Art graduate Charlotte Slingsby has developed energy generation system involving sheets of plastic with wave-like filaments.
While the cost of electricity is a constant bugbear in many countries, South Africans face a bigger problem: keeping the lights on. These blackouts prompted Cape Town native Charlotte Slingsby to seek out a solution after her family home was found to be unsuitable for solar panels.
The result was Moya (wind in the Xhosa language), a new energy generation system: sheets of plastic have wave-like filaments attached that capture tiny amounts of wind energy that can then be stored in a battery.
“We need an independent solution for today,” Slingsby said. “You see a city which functions on electricity which just falls apart, from the most basic things like opening a door [or] an electric gate. You can’t even take your car out of the garage.”
She cites serious examples, such as people on life support machines who depend on a reliable electricity supply for survival. In a security-conscious society like South Africa, the shutdown of alarm systems at night can also be an invitation to criminals.
“It is quite terrifying and it is those day to day things that you forget about. Every part of your day changes,” she said.
Moya was developed during a two-year postgraduate course in innovation design engineering that Slingsby recently completed at the Royal College of Art (RCA) and Imperial College London. The system is aimed at accumulating small pieces of energy into a larger mass, in a similar way to drops of rain gathering together to eventually form a stream.
“I thought ‘ow do you come up with a new type of material- one that can accumulate all of those abundant but lower grade forms of energy?’”
The plastic sheets have slivers of bendable filaments that stand up and are moved by gusts of air. The filaments, which are encased in plastic, work using the piezoelectric effect – the ability of some materials to generate a charge in response to pressure. In this case, when the filaments are moved by gusts of wind, tiny pieces of energy are created. For her prototype, Slingsby used a flexible film of polyvinylidene fluoride.
“They have the ability to transform strain or bending energy into electrical energy,” she said.
This energy is then passed on to a capacitor – a device used to store an electrical charge – and then eventually on to a battery. Like the rain over a mountain, “thousands of tiny drops need to be accumulated to have enough energy to bring itself to the rivers and eventually to the sea”.
From tests she has carried out on wind tunnels, Slingsby has calculated that her prototype Moya system can generate about 10% of the energy per sq metre that a solar panel can. But the advantage of her sheets is that they can be installed in areas where solar panels cannot, such as under bridges. “It is reduced in efficiency but it is looking at a new type of material which has the ability to go in far more locations. It is all about accessibility to captured energy.”
One possible location for the panels is on the London underground. “Every tube is stopping and starting all the time and as it stops you can actually line the section of tunnel where it is slowing down, which almost assists the breaking through the added drag, and absorbs this wasted energy,” Slingsby said.
In theory, the sheets can be mounted anywhere, she said, including on the side of a skyscraper, but light would still be able to get through.
It will be some time before the system makes it that far. Slingsby said it could take between five and 10 years – after significant amount of research – to get to a marketable product.
Among the problems she faces is encouraging people to accept another form of energy generation. “What has to be understood is that in the future, whatever energy we are able to absorb freely is actually really valuable and there is going to be lots of different methods with different environments no matter how you look at it,” she said.
Power to the people
The energy crisis which has hit South Africa has sparked often daily blackouts and has hit growth projections for the country. The blackouts are known as “load shedding’, where there is not enough power to cover the whole area resulting in sections being shut off. South Africa’s president, Jacob Zuma, blamed the poor infrastructure on apartheid, saying the system had been built to service only the white population. About 11 million people have power now in South Africa, twice the number in 1994. The problems have also been blamed on poor management and lack of investment.