A History of the World in 100 Objects - Dr Neil MacGregor [253]
Solar photovoltaic panels convert sunlight into electricity. If we could do this more efficiently, all our power problems would be solved. The Earth receives more solar energy in one hour than the world population consumes in an entire year. Solar panels are one of the simplest and most practical ways of harnessing the limitless energy of the Sun to provide clean, reliable and cheap power.
The panels are composed of solar cells made from silicon, which are wired together and encased in plastic and glass. When exposed to sunlight, the cells generate electricity which can charge and recharge a battery. This kit uses a range of new technologies that have recently transformed our lives: it is largely made of plastic; its photovoltaic cell depends on the silicon-chip technology that made possible personal computers and mobile phones, and the rechargeable batteries are also recent innovations. This seemingly low-tech source of energy has some astoundingly high-tech elements.
At the level of our lamp, this is a cheap and cheerful solution to basic energy needs. This technology is an economical and long-lasting source of modest energy. The ‘modest’ is important, because although silicon is cheap and sunshine is free, solar panels big enough to generate the huge amounts of electricity devoured every hour by rich countries would be prohibitively expensive: so, paradoxically, this technology which is costly for the rich is cheap for the poor.
Many of the world’s poorest people live in the sunniest latitudes, which is why this new energy source is so important in South Asia, sub-Saharan Africa and tropical America. In a poor household a small number of volts can make a very big difference. If you live in the tropics without electricity, your day ends early. Light at night is supplied by candles or by kerosene lamps. Candles are dim and don’t last. Kerosene is expensive – it consumes on average around 20 per cent of African rural income – and gives off toxic fumes. Kerosene lanterns and cooking stoves cause up to three million deaths every year, most of the dead being women, because the fumes are especially dangerous in enclosed spaces where most cooking is done. Homes are usually made of wood or other natural materials, and so are highly inflammable – at constant risk from kerosene spills.
Photovoltaic solar panels change almost every aspect of this domestic existence. Freely available light at home means that children – and adults – can study at night, improving their education and therefore their futures. Home becomes a safer place. Larger panels can provide the heat for cooking, freeing everybody from the dangers of fumes and fire. They are also able to power fridges, televisions, computers and water pumps. Many of the defining amenities of towns can now be available to villages.
Our simple lamp kit doesn’t of course do all this, but as well as light it offers something of enormous significance. Next to the socket is a symbol that is universally recognized – the outline of a mobile phone. The mobile has transformed rural Africa and Asia – putting communities in touch, giving access to information about jobs and markets and providing the basis for informal and highly effective banking networks, so local businesses can start up with virtually no investment.
A recent study of sardine fishermen in the state of Kerala in India showed the kind of changes mobile-phone access can make. It gave them weather information to make fishing safer and market information that reduced waste and increased profit by an average of 8 per cent. Another study, of mobile use in South Asia, reported that day labourers, farmers, prostitutes, rickshaw drivers and shopkeepers all said that