Appropriate Technology for the Developing World

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Putting up a PV system for home lighting and communications in Ecuador.
Putting up a PV system for home lighting and communications in Ecuador.
A rooftop PV system in Sierra Leone
A rooftop PV system in Sierra Leone provides power for lighting an educational facility.
A PV-powered health clinic in Burma.
A PV-powered health clinic in Burma.
Piping for a solar-powered water pumping system in Benin.
Piping for a solar-powered water pumping system in Benin.
Putting up solar-powered lighting at a medical training facility in Burma.
Putting up solar-powered lighting at a medical training facility in Burma.
PV electricity powers a medical center in Rwanda.
PV electricity powers a medical center in Rwanda.
School-children work on PV-powered computers in Pinar del Rio, Cuba.
School-children work on PV-powered computers in Pinar del Rio, Cuba.
Mounting an array for a medical center in Rwanda.
Mounting an array for a medical center in Rwanda.
Solar oven in Sabana Grande, Nicaragua.
Rumalda, of the Solar Women of Totogalpa, prepares to bake a cake in a solar oven in Sabana Grande, Nicaragua.
A thermosyphon solar hot water system in Costa Rica.
A thermosyphon solar hot water system in Costa Rica.
A simple batch water heater in Costa Rica.
A simple batch water heater in Costa Rica.
Low-head hydro turbine in Mae Klang Luang village, Thailand
Installing a 200 W low-head hydro turbine in Mae Klang Luang village, Chiang Mai province, Thailand.
PV-powered water pumping in Pakistan.
PV-powered water pumping in Pakistan.
Fabricating PV racks for off-grid schools in Sierra Leone.
Fabricating PV racks for off-grid schools in Sierra Leone.
Wind energy on a remote Nicaraguan island.
Wind energy powers a school and community center on a remote Nicaraguan island.
1 kW hydro system in E Wi Jo village, Tak Province, Thailand
1 kW hydro system in E Wi Jo village, Tak Province, Thailand, powers lights for 40 huts and the school.
A PV system in Burma.
A PV system in Burma.
Hauling a 3.2 kW hydro turbine in Huai Kra Thing village, Tak Province, Thailand
Hauling a 3.2 kW hydro turbine to power a school, community center, and church in Huai Kra Thing village, Tak Province, Thailand.
Milling grain with hydro power in Mbinga, Tanzania.
Milling grain with hydro power in Mbinga, Tanzania.
A methane cookstove in Costa Rica.
A methane cookstove in Costa Rica.
A methane biodigester in Costa Rica.
A methane biodigester in Costa Rica.
A doctor poses in front of the 10 kW PV array at a health center in Burundi.
A doctor poses in front of the 10 kW PV array at a health center in Burundi.
Putting up a PV system for home lighting and communications in Ecuador.
A rooftop PV system in Sierra Leone
A PV-powered health clinic in Burma.
Piping for a solar-powered water pumping system in Benin.
Putting up solar-powered lighting at a medical training facility in Burma.
PV electricity powers a medical center in Rwanda.
School-children work on PV-powered computers in Pinar del Rio, Cuba.
Mounting an array for a medical center in Rwanda.
Solar oven in Sabana Grande, Nicaragua.
A thermosyphon solar hot water system in Costa Rica.
A simple batch water heater in Costa Rica.
Low-head hydro turbine in Mae Klang Luang village, Thailand
PV-powered water pumping in Pakistan.
Fabricating PV racks for off-grid schools in Sierra Leone.
Wind energy on a remote Nicaraguan island.
1 kW hydro system in E Wi Jo village, Tak Province, Thailand
A PV system in Burma.
Hauling a 3.2 kW hydro turbine in Huai Kra Thing village, Tak Province, Thailand
Milling grain with hydro power in Mbinga, Tanzania.
A methane cookstove in Costa Rica.
A methane biodigester in Costa Rica.
A doctor poses in front of the 10 kW PV array at a health center in Burundi.

While it’s easy to get focused on our energy and economic problems here in North America, the largest portion of the globe’s population lives well below our standard of living and our standard of energy usage. Yet many aspire to our standard, so if you care about the environment, you should care about how people in “developing” areas change and develop in relation to energy. If they all follow our North American example, Earth is in big trouble.

If you care about people and want to become involved in spreading renewable energy, the developing world is ripe for your efforts. With a modest amount of money, time, and effort, you can have a big impact on families and communities. And if a good job is done, the systems will be an example for others in the community and beyond.

This article looks at specific technologies that you might consider working with in the developing world, and explores their appropriateness and cost, as well as design and implementation issues. Susan Kinne of Grupo Fenix, an organization that implements appropriate technologies in Nicaragua, says that developing-world communities have a chance to avoid some of the poor development choices we in the “prematurely developed” world have made. Properly executed, technology in the developing world can provide sustainability, a higher quality of life, and renewable energy for all.

Energy Use in the Developing World

The Alliance for Rural Electrification reports that roughly 2.4 billion people rely on burning biomass—wood, agricultural residues, and dung—for cooking and heating. About 1.6 billion have no access to electricity. Of the homes not connected to the grid, about 10% use car batteries for electrical energy storage, according to a report published by the World Bank.

Current mainstream energy technologies in the developing world tend to mirror what we see in North America:

  • Electrical grids powered by coal, oil, gas, nuclear, hydro, and diesel
  • Propane for cooking, space heating, and water heating
  • Diesel- and gasoline-fueled transportation

All of these technologies have social, environmental, and economic costs. Besides increasing air pollution and having serious environmental impacts for extraction and transportation, fossil-fuel-based electricity—when available—is often unreliable and expensive enough that poorer people cannot hook up to the grid.

Propane, diesel, and gasoline are also expensive, and often require transportation from rural areas to towns to refill portable bottles or fuel tanks. In one rural Costa Rican town I work in, buying fuel means a one- to three-hour trip by bus, horse, car, or motorcycle.

Energy sources tend to be less clean and less safe than what we are used to in the “developed” world because standards of living and environmental quality are lower, and corners get cut in the design and operation of energy plants. And because family income is much lower, these fuels tend to be relatively expensive—sometimes prohibitively—for people in the developing world. In Namibia, for example, consumers pay $0.83 per liter ($3.13 per gallon) for diesel fuel. While this doesn’t sound like much, put this in context with the country’s average annual income of about US$4,200 in 2008. In comparison, U.S. consumers paid an average of $2.46 per gallon for diesel fuel (July 2009) and had an average income almost 10 times greater than that of a Namibian.

Wood and other biomass, which are typically used for cooking and heating, come at less out-of-pocket expense in most cases, but at greater time and health costs. People (most often women and children) may spend many hours every day gathering wood, sometimes from a great distance. Increasing populations have put increased pressure on wood resources, resulting in localized deforestation. In some areas, the nearest fuelwood can be a five-mile trek (or more), according to the Food and Agriculture Organization of the United Nations. As regions become deforested, women and children are forced to walk longer distances to find firewood, leaving less time for other pursuits—like learning to read, helping with the home, and livelihoods.

The indoor air pollution from burning biomass in open fires and unvented, inefficient stoves causes major health problems. In a 2008 study published in the BMC International Health & Human Rights journal, which focused on the health effects of burning biomass fuels, rural women “reported two to three times more respiratory disease in their children and themselves” compared to those with urban-traditional and middle-class backgrounds.

Appropriate Technology

So what can renewable energy offer people in the developing world? A lot! In fact, much more for much less than it can for those of us with “developed” energy appetites. A very modest investment in renewable technology infrastructure can mean dramatic changes in comfort, health, education, income, and safety.

The primary renewable technologies used in the developing world are solar cooking;  solar water heating and purification; solar, wind, and hydro electricity; and methane biodigesters.

Solar cooking is one of the simplest and most cost-effective RE technologies. With adequate sunshine, a solar cooker can offset the use of electricity, gas, or wood for cooking, saving families money, time, and effort spent gathering, and reducing the pressure on natural resources.

A solar cooker is an insulated box with a glass top and one or more reflectors to concentrate sunlight through the glass. Even home-built versions can attain temperatures of 300°F. A wide variety of foods can be conveniently and safely cooked, including beans, rice, vegetables, tubers, and whole roasts of meat.

Because it is not a fast cooking method in most cases, solar cooking requires some advance planning and some patience—two things that people in “developed” countries may be short on, but people in the developing world come by more naturally. By preparing the evening meal right after lunch and putting it in the solar oven, the meal can be ready to go when dinnertime rolls around.

A high-performance solar cooker can be built or bought for a few hundred dollars. Simpler manufactured cookers can be purchased for less than $100, or constructed for far less in materials cost.

Solar Water Heating. Just as it can heat a solar cooker, sunshine can heat water for dish and hand washing, bathing, and cooking. If freezing is not a concern, solar hot water systems can be as simple as a black plastic bag, a coil of black pipe, or even a black-painted barrel.

Low-pressure passive solar water heaters—with no pumps or controls—are well suited for the developing world. These “batch collectors”—where a quantity of water is contained in a collector vessel and heated without cycling between a tank and the collector—are effective and practical.

Solar water heating is not common in the developing world for a couple of reasons. Many such places are located in warmer climates, where hot water is less desired: People have lived for centuries in these locales without hot water, so culturally it is not the norm. In one location, a group I was leading installed a solar water heater for a shower. Later, we were told by one of the locals that they wait until the evening to shower—when the stored water is at its coolest.

With all renewable energy technologies in the developing world, being aware of the actual need is important. Solar hot water may be most applicable in health clinics, schools, and daycare centers where there is a need to cleanse instruments or dishes. In areas where cold temperatures prevail, including mountainous regions and northern climes, solar heating systems can also be important for heating bathing water.

Solar water purification can help provide safe drinking water to the estimated 1.3 billion people worldwide who suffer with contaminated water supplies, which lead to the deaths of 2 million children each year.

Two solar technologies can help. One is solar distillation, which uses a box, pit, or cone-shaped plastic structure that allows water to condense on a piece of glass or plastic and run into a collection container. The condensed water is pure and safe to drink. Unfortunately, except for very large units, most solar stills only produce modest quantities of distilled water.

Solar pasteurization is a more practical alternative for purifying larger volumes of water. Tests have shown that bringing water to 149°F inactivates all pathogenic microbes, and solar cookers can easily achieve this. To provide temperature monitoring to assure water is adequately heated, Solar Cookers International has developed a low-tech thermometer for use with water heating in solar cookers. Placed in the water to be pasteurized, a tube, which contains soybean wax that melts at 158°F, shows when the water has achieved the appropriate temperature.

Solar Electricity. In many undeveloped areas, people rely on candles or kerosene for lighting, or disposable batteries and car batteries powering DC lights. In some cases, a rag wick stuffed into a jar of kerosene serves as illumination. A small solar-electric system with electric lighting can provide much more and better-quality light, and eliminates the ongoing costs of buying candles or fuel.

Early adopters of PV technologies tend to be community organizations such as schools, clinics, and community centers—but individuals soon see that the technology will also work in their homes. Though simple lighting systems are common, the applications for solar-electric technology don’t end there, but include water pumping, refrigeration, and electricity for appliances and tools.

Developing world solar-electric systems often take the form of a single PV module, a controller with built-in metering, a deep-cycle battery, wiring, and disconnects. Most system parts are durable and long-lasting if installed well. The battery will need to be replaced perhaps every five years, depending on the original quality and how well it is cared for.

Because most developing world PV systems are off-grid, users must be educated about the limits of the systems. Some method of monitoring the battery state of charge is crucial. Sometimes this can be as simple as a red-yellow-green light system in the charge controller, which warns users when the battery is low. State of charge may also be displayed graphically or numerically, either with a “fuel gauge” or a percentage. It is common to include a low-voltage disconnect in the controller, which automatically shuts off electrical output until battery state of charge returns to an acceptable level.

The downside to solar electricity is its relatively high up-front cost, which can range from $200 to $600 for a rudimentary system to power a few lights. Financing or subsidization from nonprofit organizations, community groups, or individuals is often necessary.

Hydro-Electricity. Where available, hydro-electricity can offer a cost-effective and reliable source of electricity. Applications range from very small homebrew systems to power a few lights to larger, “village power” systems.

These systems include some form of intake in the stream to get a portion of the water into a pipe or flume. The water runs downhill to a turbine, which consists of a runner that is turned by the water to spin an alternator. Small systems are typically battery-based but can be batteryless for specific applications.

Costs for a very small system might be $1,000 or less, if labor is cheap and homebrew equipment is used. A village power system might cost $25,000 and up, depending on the size of the system. This might sound like a lot, but for the energy delivered, hydro systems tend to be the most cost-effective. Fund-raising for village power systems can take many forms, including by charitable organizations and individuals, with some buy-in by the recipients.

The biggest drawback of hydro systems is that the resource is relatively rare. Often the falling water is not located near where the electricity is needed. And if it’s a long distance, pipe and wire costs can be high.

Wind Electricity. Of the three renewable electricity technologies, wind electricity is the most difficult to tap effectively over the long haul. A turbine’s constant exposure to the weather coupled with its difficult job of capturing the resource make many small wind installations unreliable at best. Plus, few sites have a wind resource worth tapping that is easy to access cheaply.

Wind-electric systems consist of a wind generator, a tall tower to get it up above all obstructions, transmission wires down the tower and to the controller, a battery bank, possibly an inverter, and standard distribution hardware.

Village-sized wind systems can cost from $10,000 on up, but grants and private donations can cover equipment and installation costs. As with other electrical systems, the recipients often contribute labor, food, lodging, transportation, and building materials.

If the people involved are willing to perform regular maintenance, be prepared for failure and repair, and understand that this is challenging technology, tapping the wind can be rewarding.

Methane Biodigesters. Although less common, producing methane gas with a biodigester is one of the simplest and most economical technologies used in the developing world. Only solar cooking is easier and cheaper to implement. For about $200, a methane biodigester can be built that will produce cooking gas for a family of five to seven people from the manure of two or three cows or pigs.

These systems use a long, large, doubled plastic tube as the digester—where microbial breakdown of the manure takes place. An entry pipe to add the manure-and-water slurry lies at one end. A pipe at the other end allows the digested slurry to exit after several weeks in the tube. A small tube exiting the top of the large tube vents the accumulated methane gas through a simple pressure-relief valve to the cooking stove.

Besides making cooking gas, methane systems transform a potential pollutant that can end up in streams and rivers into a more benign fertilizer. The digesters require protection from the elements and from sharp-toothed animals, but are otherwise sturdy and long-lasting. They offset the use of electricity, propane, and wood for cooking, and can be used at any hour of day or night—an advantage compared to solar cookers.

One installation I was involved with in Costa Rica was especially successful. Don Mario had enough pigs to supply gas for both his and his daughter and son-in-law’s home. On a recent visit, Mario showed off the system by cranking up the gas flame—it almost scorched the metal roof of the family’s kitchen. The gringo visitors teased him that he could fry eggs on his roof.

Access

Ian Woofenden coordinates and teaches RE workshops in Costa Rica for Solar Energy International, and also consults and volunteers on other RE projects in the developing world.

Palang Thai • www.palangthai.org

Solar Energy International • www.solarenergy.org

Sun Energy Power International • www.sunepi.org

Further Reading:

“Clean Water from the Sun,” Laurie Stone, HP62

“Cooking Under the Sun,” Rose Woofenden, HP107

“Low-Head Microhydro: Thai Style,” Chris Greacen, HP124

“RE Independence in Nicaragua,” Andreas Karelas, HP123

“Solar Cooking in Kenya,” Barbara Knudson & Mark Aalfs, HP66

“Solar Electricity for the Developing World,” Walt Ratterman,  HP119

“Turning Waste Into Fuel: Methane Biodigester Basics,” Ilan Adler, HP116

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