Biogas is one of the most obscure examples of renewable energy that scientists are trying to develop to replace fossil fuels. Biogas is defined as “a mixture of different gasses produced by the breakdown of organic matter in the absence of oxygen. Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste.”
According to Biofuel Daily, UN University’s Canadian-based Institute for Water, Environment and Health is looking at human excrement as a potent source for biogas. The University recently issued a report that states that human waste, if turned into biogas, could provide enough energy for 138 million households. It would be the equivalent of $9.5 billion in natural gas. What is more, the process of reducing human waste to biogas would also produce 2 million tons of residue that could be burned as charcoal, saving a great many trees that get cut down to create the fuel that many people use in their backyard barbecues.
In the developed world, human waste flows from toilets to waste treatment plants, where it is processed at great expense. However, 2.4 billion people lack access to modern sanitation facilities. A billion people, 60 percent living in India, defecate in the open, just as people did before the development of even the most rudimentary facilities.
Clearly, a potentially potent source of energy is literally being flushed away or even deposited on the ground, going – no pun intended – to waste.
The situation suggests that a program to create biogas from human feces would help to address two problems at once in the developing world: lack of sanitation, which causes a tenth of the world’s diseases, and lack of affordable energy. If only the human excrement of people who are obliged to defecate in the open were turned into energy, the equivalent of $200 million to $376 million worth of biogas could be created and used by 10 million to 18 million households. The sludge residue, between 4.8 million to 8.5 million metric tons, could be used for cooking or else in industrial furnaces.
Grand Challenges Canada, UNU-INWEH in partnership with the Ugandan Ministry of Water and Environment, its agencies, and other NGO and academic institutions, have started funding a program called “Waste to Wealth.” The program will help set up biogas conversion facilities in rural villages, as well as high population density areas such as schools and prisons.
Meanwhile, back in the developed world, the city of San Antonio, Texas started in 2008 to convert human waste into energy. Texas, usually associated with oil and gas, has become a center of innovation in renewable energy, with its support of wind energy and, more recently, solar power.
The good people of San Antonio flush away 140,000 tons of solid waste per year, enough to create 1.5 million cubic feet of biogas. The city has already contracted with Ameresco to sell 900,000 cubic feet of biogas per year, yielding $250,000 to San Antonio’s coffers. Other cities use methane from solid waste to power waste treatment plants. San Antonio was the first city to use waste-derived biogas on a mass scale.
Biogas from human waste is just one part of the solution to expand sources of energy away from fossil fuels to renewable energy. While San Antonio is the first American city to go into the process, San Francisco has explored ways to turn pet feces into biogas. A number of farms are converting feces from cows and other livestock into biogas, with a bonus that the residue makes a pretty good fertilizer.
Thus, human ingenuity is starting to find ways to convert a substance we are anxious to get rid of as quickly as possible, and turn it into energy.