Tofu Power and Other Cool New Alternative Energy Sources

Students and staff at the University of the West of England have figured out how to make good use of the natural result of downing a pint or two. They’ve created a pee-powered urinal stall for their Student Union bar. The stall uses live microbes that feed on urine to power a microbial fuel cell, which, in turn, provides electricity. The project is a collaboration between the university and Oxfam, which says the pee-powered toilet could be a model for similar units in refugee camps, where dark stalls at night are a safety hazard. Since humans collectively produce nearly 3 billion gallons of urine each day, this has much wider implications for clean energy as well.

In small towns on the Indonesian island of Java, making tofu is a common home business. The process uses an enormous amount of water—nearly four gallons of water per pound of tofu. Acetic acid is added to the water to make the tofu solidify. The resulting acidic wastewater traditionally goes to waste. But now, thanks to a new initiative, the wastewater can be treated with bacteria to create a biogas, which is then used to power stoves in the tofu-makers’ homes. This cycle is cleaner than using traditional stove fuel, and saves the tofu-makers on gas costs. Right now, about 150 home tofu-makers in the village of Kalisari are trialing the tofu power project, which the government hopes to spread across the country soon. 

The average person walks 3,000 to 4,000 steps a day. While this may not be enough for good health (doctors recommend at least 10,000), it’s plenty to power a light or two. Several startups are working to harness the kinetic energy of human footsteps to keep streets and offices lit. In the UK, Pavegen produces special floor tiles filled with circuitry to enable this process. Their tiles have been installed at Heathrow airport and the London Tube, and they were used during the 2014 World Cup in Brazil to keep the lights on at local soccer fields so kids could play after dark. 

Cows fart and burp an enormous amount of methane, a greenhouse gas. According to the United Nations, their methane emissions account for 37 percent of all human-related methane production. What if these smelly gases could be harnessed for good? That’s what scientists in Argentina (one of the world’s largest beef producers) were trying to figure out when they designed these “cow fart backpacks.” The backpacks are basically plastic balloons strapped to the cows’ backs, with a tube running into the cows’ digestive systems to extract the methane and channel it into the backpack. Each cow produced about 300 liters of methane a day, enough to run a car for 24 hours. How the cow farts might actually be transferred to cars or other fuel-dependent devices remains under investigation. 

The U.S. Department of Energy considers algae such a promising source of energy it recently invested $18 million in various algae fuel projects. The biggest contribution is $9 million for the U.S. School of Mines, which will research how to “enhance overall algal biofuels sustainability by maximizing carbon dioxide, nutrient, and water recovery and recycling, as well as bio-power co-generation.” The Department of Energy hopes to reduce the price of algae biofuels to $5 per gas gallon equivalent by 2019, and $3 per gallon by 2030. 

The human body produces an enormous amount of energy. Some is used to power our bodily functions, but much is wasted, most in the form of heat. Various recent projects have been aimed at turning that wasted heat into green energy. There’s a flashlight than runs on human body heat instead of batteries. There’s an armband the turns heat into power. There’s a “power felt” fabric that harnesses body heat to convert into electricity. Perhaps soon we’ll be able to leave home without phone chargers, relying only on our own natural power.