IMAGE: Steve Stankiewicz

UGANDA’S DAMS AND GRID : The mighty Nile River feeds Uganda’s main 200‑megawatt dam at Owen Falls, near the north shore of Lake Victoria, not far from Jinja. The dam feeds the national grid, which transmits ­electricity via 33-kilovolt lines [in red] that roughly follow Uganda’s major roads. Small hydro plants also feed the grid, notably one run by a cobalt-processing operation in Kasese, in the far west of the country in the foothills of the Ruwenzori mountains. Click here for the .pdf of the image.

In the gorgeous Ruwenzori mountains of western Uganda, on a ridge above a fast-moving creek, a young man leans against a mango tree, a machete dangling from his arm. It is his job to guard one of the funkiest, tiniest dams in the world.

It's a hunk of concrete, about four meters across, that interrupts a natural waterfall, diverting water into a large reservoir. That pool drains into a rusted steel pipe that runs along the creek and then drops sharply into a white stucco-covered bungalow the size of a walk-in closet. Inside the bungalow, a turbine generator capable of producing 60 kilowatts churns out electricity, which is carried via underground wires to the Kagando Christian Hospital, 3 kilometers away.

The zany contraption is the hospital's chief source of electricity, and it is incredibly reliable—five years have gone by since a turbine blade needed replacing. The entire system cost less than US $15 000.

At a state-of-the-art hospital, 60 kilowatts would just barely keep an MRI facility going, but here in this rural corner of East Africa, it's enough to keep 100 nurses and doctors, and hundreds more patients, bathed in light, and to power their dental, surgical, and lab equipment, as well as their kitchen and laundry.

That explains the presence of the man with the machete: he works for the hospital, and he is protecting the dam from vandals. The little hydro facility has brought life and some semblance of order to a place where politics and official infrastructure have generally meant failure and disappointment.

"The government has promised and promised to bring electricity to this village and never has," says Sabuni Seezi, who maintains the hospital's microhydro. "So we did it ourselves."

And what works for Uganda has enormous promise all over sub-Saharan Africa, the most energy-poor region in the world. Excluding highly developed South Africa, the region has only about 30 gigawatts of installed capacity, about the same amount as Poland. But to spread the benefits of microhydro would take a seismic shift in the continent's usual electrification paradigms and—perhaps more ambitiously—a renunciation of the crippling mix of politics and patronage that have left the continent with some of the worst electrification rates in the world. And nowhere are the tensions over microhydro more apparent than in Uganda, with its many rivers, including the Nile. Here, the struggle to balance the potential for both large and small hydroelectric projects has already begun.

Big dams still dominate Africa's electricity scene. They have been at the center of infrastructure development on the continent for 50 years, ever since Egypt built the 2.1-gigawatt Aswan Dam on the Nile and Ghana built the 768-megawatt Akosombo Dam on the Volta River. Now in addition to its main dam on the Nile at Owen Falls near Jinja, the Ugandan government is planning to build two more large dams on different points of the Nile at an estimated cost of $750 million. The larger and more expensive, at Bujagali, was put on hold in 2002 and is now being revived.

Uganda is not alone among African countries in its reliance on big hydro; nine others receive at least 80 percent of their electricity from hydro, including Cameroon, Ethiopia, Ghana, Mozambique, and Zambia. Hydro contributes more than 60 percent of the electricity in Angola, Benin, Kenya, Namibia, Rwanda, Sudan, and Tanzania.

Because large dams are so expensive, they carry great risks, especially in drought-prone areas, and require capable management by government. Microhydro systems such as the one at the Kagando hospital are appealing because they cost less, reach places far outside the national grid, and give local communities a direct stake in their power systems. They also don't require the involvement of national government agencies—which, in Africa, are often corrupt, incompetent, or both.

According to the Uganda Ministry of Energy, the country has three working microhydros, and a dozen more are in various stages of planning. "These microhydros are worth building in large numbers," says Philippe Simonis, a German energy expert who works for the Ugandan government. He has advised the government to consider a crash program to spread microhydro projects all over the country. "It is possible to have hundreds, even thousands of them in Uganda alone, and tens of thousands around Africa," he says.

Uganda's main dam at Owen Falls is rated at 200 MW. Even in the best of times, the dam supplies electricity to just 5 percent of Uganda's 28 million people. And these are hardly the best of times. Because of a drought in East Africa, the dam is producing half its normal output, blacking out huge swaths of Uganda's neighborhoods and industrial centers.