It's easy to think of the energy shortage in the developing world as being all about finding ways to generate electricity from the sun and wind to power the 81 percent of African rural areas that still are off the grid.
But in places where people are accustomed to living without electric lights, appliances and electronic gadgetry, a 2011 World Bank report says that the main energy source is biomass -- small stoves fueled with wood or charcoal, which supply heat for warmth, cooking, boiling water and other activities of daily life.
In many developing countries, gathering wood and selling it is one of the major industries, providing jobs. The charcoal-producing industry in sub-Saharan Africa, for example, is projected to employ 12 million people by 2030.
There's a major downside to the reliance upon wood stoves. The cheap, antiquated stoves used by rural dwellers in Africa and elsewhere aren't very efficient, and they spew smoke that contains black carbon, consisting of tiny particles that are only partially burned. It's the same stuff that's found in fireplace soot, and it's a serious health risk to the people who breath it in.
Beyond that, black carbon gets into the atmosphere where it's many times more potent than more plentiful carbon dioxide. Black carbon is a significant contributor to the greenhouse effect that's altering our planet's climate.
"It absorbs sunlight so much more strongly than any other type of pollution," explained Christopher Cappa, a University of California, Davis professor of civil and environmental engineering.
Project Surya, a research effort that studied a handful of villages in rural India a few years ago, found that black carbon emissions rose by 500 percent in morning and evening cooking hours, when wood stoves were in use.
That's why in recent years, international organizations have worked to find a way of reducing the developing world's black carbon output. According to the World Bank report, past efforts to get rural dwellers to switch from using wood fuel haven't yielded much result. That's why the focus now is upon developing and distributing a new generation of energy-efficient, cleaner wood stoves to replace the old ones.
To that end, the UN has formed a public-private partnership, the Global Alliance for Clean Cookstoves, which is coordinating efforts to get 100 million households worldwide to cook more cleanly.
It's not been an easy transition. "There remain substantial economic and cultural challenges to having these technologies adopted," Cappa said. "People are currently working to develop cookstoves that better replicate the feel of traditional stoves but that emit less pollution to facilitate increased adoption."
One potentially powerful innovation is the BioLite HomeStove, created by product developers Alec Drummond and Jonathan Cedar, which contains a thermoelectric generator that converts some of the fire's heat into usable electricity. That current, in turn, is used to power an internal fan, which forces more air into the fire and improves combustion, so that it's cleaner and nearly smokeless.
Another outfit has developed a the Save80 stove, a super-efficient wood stove that reportedly requires 80 percent less wood.
Nithya Ramanathan, an assistant research professor at UCLA, is co-founder and president of Nexleaf Analytics, a startup that's using mobile phone sensor technology to improve health and the environment. In India, another place where millions of people rely upon wood stoves, Nexleaf is studying how various next-generation clean stoves actually perform in reducing emissions.
"Our findings so far indicate that stove breakage and a lack of stove maintenance are a much bigger problem than anybody thought," said Ramanathan, who also was a participant in Project Surya. "Our monitoring shows that some women cook for several months, but then cooking abruptly drops off. Follow-up visits reveal that these users' stoves are broken in a way they are unable to fix."
Improving stove designs so that they don't break as often, and creating a system for maintaining them is crucial for success, she said.
But once that's achieved, the Big Data gathered by monitoring also may help drive the switch to clean technology. Ramanathan says the data can be used to establish a market for black carbon offsets, similar to the industrial-scale cap-and-trade emissions markets in developed countries. That way, rural dwellers actually would be able to earn money by reducting their black carbon output.
Cutting black carbon output actually could be a major blow against climate change, as an article from the Yale Climate Connections website notes. Unlike carbon dioxide, which can stay in the atmosphere for a millennium, black carbon tends to disappear from the air and return to Earth in just a few days or weeks. That means that reducing black carbon output could have a quicker impact on slowing the rate of climate change.