Two thirds of the rural population in developing countries are without electricity. This leaves limited options for lighting.
Many turn to kerosene or paraffin oil. It is estimated that 88 billion liters of kerosene are burned purely for light. One liter of kerosene is estimated to produce 3kg CO2 when burnt.
Research has shown that basic oil lamps typically produce just 1% of the light of a 100W light bulb.
Nokero is one of many companies making LED solar powered lights and solar powered mobile phone chargers and battery chargers. The N200 is about 13.5 lumens on high, and about 5 lumens on low. DBT 1.9 hours when tested with 5000 watt-hrs/m^2-Day on hi setting, 6.6 hours on low. The battery will last for approximately 1.5 years, and can be replaced to keep the bulb in operation. The Nokero N200 can withstand rain, but is not waterproof and cannot be submerged. Product performance varies based on intensity of sunlight and duration of charging time.
The N200 lantern made by another American firm, Nokero (for “no kerosene”), has a design inspired by a light bulb, and costs about $15. It worked well for cooking, cleaning and sitting around a table, but was deemed less suitable for studying. The Solar Muscle, a solar lamp made by Flexiway, can be used as a desk light. Its compact, square design, with a solar panel on one side and LEDs on the other, also allows several lamps to be snapped together to make a larger panel. The square design arose after an earlier, circular version was mistaken for a landmine, says James Fraser of Flexiway. The firm can pack 2,750 of its $10 lamps in a cubic metre—a plus in countries where transport is expensive. They are being distributed by NGOs in Papua New Guinea and several African countries.
The best solar lamp among those tested was the Sun King, produced by an Indian company, Greenlight Planet. It was purchased off the shelf from an African supermarket for $24. The Sun King’s almost dazzling light was appreciated by users, as was its seemingly unbreakable design. The awkward-looking wire stand worked well. The lamp’s only drawback was that its solar panel is separate, rather than being built into the lamp.
For the next decade the mobile phone will be joined by the solar-powered lamp, made up of a few light-emitting diodes (LEDs), a solar panel and a small rechargeable battery, encased in a durable plastic shell. Just as the spread of mobile phones in poor countries has transformed lives and boosted economic activity, solar lighting is poised to improve incomes, educational attainment and health across the developing world.
Phones spread quickly because they provided a substitute for travel and poor infrastructure, helped traders find better prices and boosted entrepreneurship. For a fisherman or a farmer, buying a mobile phone made sense because it paid for itself within a few months. The economic case for solar lighting is even clearer: buying a lamp that charges in the sun during the day, and then produces light at night, can eliminate spending on the kerosene that fuels conventional lamps. Of the 1.4 billion people without access to grid electricity, most live in equatorial latitudes where the sun sets quickly and there is only a brief period of twilight. But solar lamps work anywhere the sun shines, even in places that are off the grid, or where grid power is expensive or unreliable.
The potential savings are huge. According to a recent study by the International Finance Corporation, an arm of the World Bank, $10 billion a year is spent on kerosene in sub-Saharan Africa alone to illuminate homes, workplaces and community areas. Globally, the figure has been put at $36 billion. Flexiway, an Australian-Argentine maker of solar lamps, found in its trials in Tanzania that households often spent more than 10% of their income on kerosene, and other studies have put the figure as high as 25%. And kerosene does not merely eat up household income that could be spent on other things. It is also dangerous. Kerosene lanterns, a century-old technology, are fire hazards. The wicks smoke, the glass cracks, and the light may be too weak to read by. The World Health Organisation says the fine particles in kerosene fumes cause chronic pulmonary disease. Burning kerosene also produces climate-changing carbon-dioxide emissions.
Demand for cheap, efficient lighting is only going to grow. Even in the best-case scenarios, the number of people without electricity will tick up to 1.5 billion by 2030, as population growth outstrips electrification. The rate of innovation in delivery models, technology and design, in both rich and poor countries, suggests a bright future for solar lamps—and a slow dimming of kerosene’s flame.