Alumni profile/Marianne Walpert: Lighting the way

Alumna Marianne Walpert, founder of solar light nonprofit TanzSolar (photo by Heimo Schmidt)

Marianne Walpert is no stranger to breaking down barriers.

Having earned her bachelors degree at UC Santa Cruz in the male-dominated disciplines of math and physics, she became interested in solar technology in graduate school, then broke into the building trades installing residential solar electric systems. That there was no one else in the business didn't slow her down.

"Semiconductor devices that turn sunlight into electricity?" she says, still enthusiastic about the technology she's championed her whole career. "I mean, it's the coolest thing in the world! It really is."

Building grid-connected photovoltaic systems in the early1990s, she quickly encountered daunting problems for solar homes. Utilities offered to pay only wholesale rates for home-made power, which made home photovoltaic power to the grid impractical and non-competitive.

So Walpert went to Sacramento and got the law changed to permit "net metering," cutting the red tape utilities were introducing and forcing them to pay retail prices for energy produced by homeowners. "We fought it through," she says, "and we won." America has followed her lead, with the net metering she pushed for in California now the law in 46 states.

By 2006, Walpert (Oakes '79) was looking for new challenges. "After 20-plus years of working in the photovoltaic industry," she says, "I felt that I had done everything there is to do in solar." That's when an old friend called from Tanzania, saying, "We really, really need solar here."

For Tanzanians, the always-on grid power we take for granted is beyond reach. Prohibitively expensive to hook up in the few places it's available, Tanzanian grid power is also resolutely unreliable: the 14 percent of Tanzanians "on the grid" demand more power than the nation's power plants can generate. The result is widespread power rationing.

Without reliable power, Tanzanians use kerosene lanterns for light. Even after state subsidies, though, a liter of kerosene costs about a day's wage. "Typically," Walpert says, "people say about a third of their income goes to buying kerosene for these lanterns." The lanterns, often little more than tin cans with wicks stuffed in, cast a weak light—enough to carry out household chores, but not enough to read by. Worse, they produce a toxic aerosol brew of volatile organic compounds, carbon monoxide, and fine soot, and cause an appalling number of burns and fires.

In response, Walpert created TanzSolar, which, since 2007, has brought simple, easy-to-use solar light kits to villagers in Northern Tanzania's rural Lake Zone. Consisting of a small solar panel, a battery, a charge controller, and LED bulbs, each kit produces a brighter, cheaper, safer light for work, study, and home security.

A solar light costs TanzSolar about $40, half of which is defrayed by donations. Within a few months, the lamps earn back their price in unburned kerosene, and owners can put money they would have spent on kerosene to other essentials. Newer versions offer a USB port for charging cell phones.

With TanzSolar launched, Walpert has turned the reins over to the Tanzanian staff and is now dedicating herself to fundraising. Her next challenge is the Africa Solar Fund, a nonprofit to help fund TanzSolar and similar initiatives in Africa.

"We put 20 bucks to this light," Walpert says. To Americans, "it's a night at the movies, but these Tanzanians' lives are changed forever."

This article appears in the fall 2011 issue of Review magazine.