An abandoned farm in rural Spain, a mile from the nearest tiny village, is the unlikely site of cutting-edge energy technology. The new farmhouse under construction on the property will eventually be powered partly by the owners’ poop.
The mini waste-to-energy system takes organic waste–straight from toilets, from kitchen scraps, and from horse manure on the farm–and converts it into energy that can provide hot water, heat, and gas for cooking.
The same technology is becoming more common at a large scale, like a food waste-powered plant in the U.K. (which sends energy directly back to the supermarket that threw out the food). But the new house in Spain was designed to show that the tech is also feasible for individual homes.
“This is a demonstration facility, to show people that it’s technologically and economically viable on a small scale,” says Meghan Sapp, one of the co-founders of a startup called PlanetEnergy. “Anywhere up from here, it’s doable.”
Sapp and her partner Iñigo Arana, who will live in the home, created the startup on a mission to convert homes, apartment buildings, and entire communities to new systems that make use of waste on-site.
“We make entire integrated systems, looking at the consumption and production of waste streams holistically,” she says. “So we can take into consideration sanitation, as well as all kinds of agricultural waste, municipal solid waste, and then add in solar and wind when necessary.”
For a rural home like the farmhouse they’re rebuilding, making use of waste can ultimately save money.
“We’re disconnected from the grid,” Sapp says. “Normally, where we are, you would put in a septic system. This is basically an adapted septic system, so you can take advantage of what would otherwise be lost by using a regular septic system.”
The engineers estimate it will take about five years for the the system at the farmhouse to pay for itself. “It costs a bit less to connect to the grid, but you would be paying the bill for the rest of your life,” she says. “We’ll only pay maintenance.”
The system uses bacteria and enzymes to speed up the breakdown of waste, then captures methane to power the house. It will generate more than enough power for heating and gas, so the couple will also use it to heat a hot tub. The tech will also provide extra water and fertilizer for their garden.
It’s essentially the same as an industrial waste-to-energy plant, but with a few tweaks to make it affordable for individuals. “Large scale works very well because of the economy of scale,” says Sapp. “So what we’ve had to do is engineer it so that the front end processing is a bit more manual, but the system is the same.”
The same technology can also be scaled slightly up for more people. The startup is working on a proposal for a project in Spain that would recycle waste for an apartment complex. They’re talking to wineries and cheesemakers about using agricultural waste to power their operations. And they also plan to bring the technology to off-grid communities in places like rural Africa, providing both sanitation and energy where people currently don’t have either.