June 5, 2010 -- Resourceful as he was, it's doubtful that even the MacGyver of television fame would know how to make a battery powered by dirt.
Thursday night, at a World Science Festival presentation in New York, Hugo Van Vuuren, a Fellow at The Harvard School of Engineering and Applied Sciences, explained how he and his partners, who met as undergraduates at Harvard, figured out how to harvest power from some of the most abundant stuff on Earth: soil.
During an event featuring "modern MacGyvers" -- inventors, biologists and engineers innovating for the developing world -- Van Vuuren described how the microbial reactions in a bucket of mud could be used to provide electricity to approximately 500 million people in Africa who don't have access to it.
Van Vuuren said that so-called "microbial fuel cells" are based on science that was discovered about 80 years ago, but until now it was considered too weak to use.
"It's just a technology, a science, that creates very small amounts of electricity -- a trickle charge -- that up till now has not been useful for us because we needed to power refrigerators and cars and big things," he said. "But now, we as a people, all of a sudden, we realize that there are 4 billion other people who live on less than $5 a day and they are a market."
Building on research into microbial fuel cells, Van Vuuren said he and his partners created a battery that derives power from the energy created as soil microbes break down organic matter. As long as the soil stays moist enough, he said the soil can continue to generate energy for eight to 12 months (in the lab).
The team created a start-up called Lebone (which means light, lamp or candle in Southern Africa's Northern Sotho language), and in 2009 they won the Popular Mechanics Breakthrough Award for their battery design.
It's a prototype now, but Lebone is working to scale production of the battery to move the cost to about $10 per battery, down from about $30 or $40, so that it can start distributing the battery in sub-Saharan Africa.
Van Vuuren wasn't the only "modern MacGyver" recognized on Thursday. Meet three others.
Winston Soboyejo's Solar-Powered, Camel-Transported Fridge
For some in the United States, camels may just be animals to admire in the zoo. But in remote parts of Kenya and Ethiopia, they're lifelines for people who need the vaccines that they carry.
"The problem is one of getting vaccines to people in remote places -- places you can't approach by Land Rover or Jeep," said Winston Soboyejo, Director of the Undergraduate Research Program at The Princeton Institute of Science and Technology of Materials.
Camels, which can carry 600 lbs. and walk through deserts over difficult terrain without water, are relied upon by community health clinics to transport vaccines to those areas. But, he added, there are daily vaccine losses, without refrigeration, there were daily losses because the ice inside the containers carrying vaccines began to melt once the containers were opened.
To address the problem, Soboyejo and his team invented a solar-powered, camel-transported refrigerator. But getting there took a lot of trial and error, he said.
For starters, he said, "At Princeton, you need access to camels."
The team tested an early prototype at the Bronx Zoo and continued to refine the device in Ethiopia and Kenya.
Ultimately, they devised an eco-friendly bamboo structure that sits on the camel's back and can support a fridge on one side and a battery on the other. A flexible solar panel, draped over the structure harvests the energy, which is stored in the battery that is used to power the refrigerator.
StoveTec Stoves Improve Health and the Environment
Believe it or not, cooking with an open stove can be as hazardous to human health as smoking.
According to Benjamin West, general manager for the Cottage Grove, Ore., StoveTec, about 3 billion people in the world use open stoves to cook daily meals. For those people, sitting in front of the open fire is like smoking three to five packs of cigarettes a day, he said.
"Imagine for me taking a fire that you would build at a campsite and putting it in your home and cooking macaroni or cooking breakfast," he said. "The thing with that is that's how really half the world cooks."
West said that not only do open fires leave people susceptible to pneumonia and other diseases that come from cooking with an open fire, burning biomass (or wood) contributes to deforestation and greenhouse gases emissions.
"The smoke that kills 1.6 million people each year is also a contributor to climate change," West said.
But with a simple $8 stove, StoveTec is trying to change all of that.
The company's stove uses 40 to 50 percent less fuel and reduces emissions by 50 to 70 percent, he said.
The ceramic chamber can get hot enough to burn off the greenhouse gases and smoke before they leave the chamber, and the opening (where the wood is inserted) is optimized to provide just the right amount of airflow, so that emissions and fuel use can be kept at a minimum, he said.
Pamela Ronald's Bionic Rice Resists Disease, Flooding
For more than half of the world's population, rice is the staple food. So when rice crops fail, millions of people can suffer, meaning that a strain of rice that can withstand outside elements would be very valuable.
"Small improvements in farmer productivity in rice can have a dramatic effect on feeding a hungry world," said Pamela Ronald, a plant pathologist at the University of California, Davis. "And because the population's moving from 6.7 billion now to 9.2 by 2050, there is a great need to produce more food with the same amount of water on the same amount of land."
She said that to increase productivity, farmers need infrastructure, markets and social and economic support, but the most critical ingredient is rice seed.
To help enhance farmers' rice yield, Ronald's lab studies the roles that various genes play in how rice responds to changes in the environment. She said there are about 25,000 rice genes, and scientists have uncovered the functions of a few hundred.
Ronald said her lab had successfully genetically engineered rice to be more resistant to disease and flooding, two major reasons for crop failure.
About 25 percent of the world's rice is grown in flood prone areas, but the new varieties can withstand up to 17 days of flooding and are now being used in India and Bangladesh.