Solar-Powered Toilets of the World: A Comprehensive Guide

For the first time in perhaps ever, solar-powered toilets are a prominent news item. I guess we can thank the world's wealthiest philanthropist: Bill Gates just gave a $100,000 cash prize to designers at Caltech who engineered a toilet that employs a...

Aug 15 2012, 5:30pm

Today is the day that solar-powered toilets have become a full-fledged mainstream news item. I guess we can thank the world’s wealthiest philanthropist: Bill Gates just gave a $100,000 cash prize to designers at Caltech who engineered a toilet that employs a solar panel to, as Reuters reports, produce “power for an electrochemical reactor that breaks down feces and urine into hydrogen gas, which can be stored in hydrogen fuel cells.” And that power can be used to keep the toilet’s lights on at night or during rainy days.

Clearly, it’s a hell of a toilet. It’s the sort of self-sustaining loo that Gates and others hope can one day be installed across the developing world, where there are currently 2.6 billion people without access to latrines of any kind. But solar-powered toilets are hardly a novel concept; for years, designers and developers have been striving to build the perfect PV-powered commode. Both Dubai and Portland, OR already boast toilets that run on solar power, and engineers are experimenting with johns that harvest rainwater and boast LED fixtures, too.

Thus, without further ado, I give you the solar-powered toilets of the world. In the future, this is where we will urinate in public.

The Surprisingly Pleasant Portland Loo

Public toilets are notoriously dank, fetid places to be entered only in cases of utmost emergency. In urban neighborhoods, they’re blights; magnets for illicit activities and apparently repellent to the steeliest custodian. But not in Portland. The hipster capital of the nation somehow managed to come up with a public toilet, the Portland Loo that’s both perfectly and pleasantly functional and that discourages activities like in-stall drug dealing and bum sex. It’s also solar-powered, of course, so it requires no permanent attendant.

Green Launches describes the design:

Erected out of stainless steel wall panels, the cylindrical bathroom is designed to be five feet wide and eight feet tall. It will sport a sink on the outside and see-through slats down low so police can check for unhealthy or nasty behavior. It will have a hard connection to water and sewer and solar panels to power the light that will come on in the evening and warm the pipes to prevent against freezing.

As a result, somewhat weirdly, Portlanders actually love the public toilet. It’s got a Facebook page, Twitter account, and scores high on Yelp! reviews.

Bill Gate’s Hydrogen Fuel Cell-Outfitted Solar Toilet

As described above, Gates is championing this throne as the best effort to meet his foundation’s challenge: design a toilet that requires no running water, no electrical connections, and can turn the waste into useful energy. Tall order.

Earth2Techling explains how Caltech got it done:

Caltech's winning toilet flushes down to a holding tank under the floor, where the solid material sinks to the bottom … When the liquid reaches a certain level, it flows through a tube into a "sun-powered electrochemical reactor." The reaction oxidizes the chloride in the urine, killing microorganisms in it. The resulting hydrogen is siphoned off, free to be used by the toilet's owners as a fuel. The treated water is filtered and reused the next time someone sits on the toilet. The whole thing is powered with solar energy.

Boom. Self-sustaining poop regulation.

Dubai’s Solar-Powered Poop Chutes

Dubai already a fleet of electric public toilets, so the booming, resource-starved city decided it might as well power them with the sun. Local newspaper the National reported at the time of the project’s debut last year that “About 80 public toilets across Dubai run on electricity, including the fluorescent lights, exhaust fans and small water pumps. This power source will be replaced by solar power in the experimental toilets.”

Solar panels were then installed on a couple test sites. Project coordinators assured the public that the panels were installed in a manner that matched “the architecture of the neighbourhood and will save electricity.” And so, construction has since begun on more solar-powered public poop chutes in the nation where it is probably illegal to say “poop chutes.”

Rainwater-Harvesting, Sun-Powered John of the Future

Belgian design firm Bundl came up with the concept for ZESS, another snazzy-looking solar-powered public can. But this one does the strictly solar-powered set one better—it harvests rainwater for use in its plumbing system.

Bundl explains that ZESS “is it distinguished from the others by the design, but also by the function of the whole. This toilet can function as an autonomous unit thanks to the use of solar energy and rain water. Even on sites where an electricity and/or water network is available, ZESS will first opt for the ecological way.” (That’s a text translation, so cut the grammar some slack.)

Clearly, the world needs millions and of millions more public toilets—nearly a third of the booming human population lacks access to sanitation, which can inflict serious health woes on communities. These solar-powered systems make the prospect of building some pretty solid toilets even before there’s advanced sewage or electrical infrastructure. And even in the rich world, the sun-powered heads clearly make life easier, more sustainable.

Toilets are an all-important, typically unheralded pillar of modern society. That solar power can help bring the most modern toilet tech to the masses is an important development indeed; vast improvements in community health and sanitation stand to be made. Friends, it now seems obvious—the future of public defecation is solar-powered.