Delivering Green Hydroelectric Power-to-Go in Rwanda

Nov 25, 2008 - Larry Greenemeier - Scientific American

HYDROPOWER: A team of Dartmouth College Thayer School of Engineering students (working through the school's student-run Humanitarian Engineering Leadership Project, or HELP) designed, built and installed a mini hydroelectric turbine in Rwanda. They hope it will deliver environmentally friendly power to the country's Banda region, which has a population of about 6,000. Image courtesy of Dartmuth's Thayer School of Engineering	HOMEMADE HYDRO: Thayer students worked with locals to build the second turbine from scrap materials. Whereas this turbine has proved more difficult than the first (which was made in Canada), it is now up and running and being used to charge batteries. Image courtesy of Dartmouth's Thayer School of Engineering	HEAVY BURDEN: Some Banda residents must walk dozens of miles over the area's rough terrain to a site where they can recharge their 40-pound (18-kilogram) car batteries. Image courtesy of Dartmouth's Thayer School of Engineering

As scientists and engineers puzzle over how to inexpensively deliver thin-film photovoltaic solar cells, wave and tidal powered turbines, hydrogen-fueled cars, and other advanced technologies to reduce world dependence on fossil fuels, a team of college engineering students is working on a decidedly lower-tech, though no less difficult, project they hope will bring hydroelectric power to remote areas of the African country of Rwanda.

The group, part of Dartmouth College's Thayer School of Engineering student-run Humanitarian Engineering Leadership Program (HELP), in September set up two hydroelectric turbines powered by a local water source in Banda, a mountainous region at the edge of Nyungwe National Park with a population of around 6,000.

The first site's turbine—prebuilt and taken to Banda by the students—generates enough energy to charge six 12-volt batteries concurrently. "While the total power (310 watts) is relatively low by American standards, its enough to charge up to 30 batteries per day, each of which only needs to be recharged once every two weeks," engineering student Eric Trautmann, 23, wrote in a September 19 blog on the group's Web site. Trautmann, who is pursuing his masters in robotics, is one of 15 Thayer electrical, environmental and mechanical engineering students working on the Rwanda project. Eight of the students—including Trautmann—have traveled to Banda since June to get the turbines up and running, while the other seven helped plan the project, design the turbines, and provide backup support from the U.S.

The second turbine, built from scratch with local parts and labor, has been more troublesome. The turbine's charge controller—used to ensure batteries do not overcharge—has malfunctioned repeatedly, says student Derek Brand, 22, who recently returned from Rwanda after a three-month stay. While in Africa, Brand needed to travel several hours to another village in search of new parts to correct the problem. The turbine is now up and running and producing 300 Watts of energy.

The students plan to, with help from the locals, upgrade the sites over time to improve their output to 1.5 kilowatts, enough meet all of the village's electrical needs and more. But for now, Brand says, increasing power isn't a top priority because the combination of energy produced by both sites is "more than enough to meet the town's demand, at least until we return next summer."

In the meantime, some of the Banda people use the turbine sites to recharge the car batteries that serve as the main power source for their homes (providing the juice they need for lighting and to charge smaller batteries used in cell phones, flashlights and radios). It is not uncommon for a Banda resident to walk dozens of miles over the area's rough terrain with a 40-pound (18-kilogram) battery balanced on his or her head to the nearest town with electricity, sleep the night there, and then walk back home the following day with the recharged battery.

One of the project's aims has been to use locally available components and manufacturing techniques to make the turbines so the locals could build more of them on their own. "This ensures sustainability and stimulates the local economy instead of importing foreign-made components," says Benjamin Koons, 22, a Thayer student set to graduate in March. "HELP could add a fresh way of looking at hydro projects in the area, driven by locally available materials and labor as opposed to small efficiency gains and profits."

The students point out in their blog (which was closed to the public earlier this month due to complaints from some of Rwanda's ministers) that there are areas of the country already using small hydroelectric turbines, but that those machines cost as much as $4,000 per kilowatt to produce energy, a hefty sum for people here, where the average annual income is $260. The Thayer team's ultimate goal is to develop systems that can reduce that cost to less than $500 per kilowatt by using local parts and labor instead of expensive foreign parts that are tough to come by in this rural pocket.

The hope is that Banda will serve as a proof of concept and encourage the building of additional hydropower turbines throughout Africa, which is heavily reliant on kerosene for lighting. Africans consume nearly 3.8 million tons of kerosene annually, making it a significant contributor to climate change-causing greenhouse gas emissions, according to a report by the students.

The Thayer students anticipate the annual cost to run the hydroenergy turbines—including purchasing batteries and compact fluorescent bulbs—will be about $50 per family. Banda families are already paying between $50 and $60 a year for kerosene, "making our system very competitive with kerosene lighting, while providing a much higher quality light," Brand says. "Furthermore, the cost of kerosene is tied to the cost of oil, which will probably rise in the future."

African countries have been the recipients in recent years of a number of low-tech gadgets designed to improve education, provide access to clean water, and protect people there from disease. London-based Pump Aid (a charity formed by three teachers living and working in rural Zimbabwe) developed the $740 Elephant water pump to help villagers gain access to clean water as well as the Elephant toilet, an outhouse sans plumbing that can be constructed using a slab of concrete and other readily available materials for about $30.

Vestergaard Frandsen Group, a Switzerland-based philanthropy organization, makes a number of basic technologies targeting Africa, including the LifeStraw (a powder blue plastic tube with filters that clears typhoid-, cholera- and diarrhea-causing microorganisms from water); ZeroFly (a sheet of plastic laminated with insecticide used to create temporary shelters); and PermaNet (an insecticide-treated curtain that protects against disease-carrying insects). Meanwhile, South Africa's Freeplay Foundation, a group that promotes access to radio broadcasting in remote pockets of Africa, offers communities in Rwanda and elsewhere its Lifeline radio, which is recharged by winding a spring-loaded handle.