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Could American Excrement Power Our Electricity Grid With Renewable Energy?

by Neal Litherland 3 months ago in Sustainability · updated 3 months ago

Short Answer, Yes. Long Answer... It's Complicated

If you pay attention to the news, particularly to tech news, you likely came across the toilet that converts poop to cryptocurrency. Located on a campus in South Korea, the process for this system is fairly simple. Students log in with their ID in the bathroom (we've all got our phones in-hand anyway), do their business, and then a vacuum system sucks away their "donation" as it's called. The waste is deposited in a tank, and then allowed to break down, producing methane. The methane is burned to create power, helping keep the university sustainable.

If you read that and thought it's amazing that we live in the modern age where we can turn poop into power, I have unfortunate news for you... the only new aspect of this is the cryptocurrency. We've had the capacity to do this for decades... and the fact that we haven't embraced it more fully is one major reason our emissions have remained at such staggering levels.

The Wonderful World of Anaerobic Digestion

What is anaerobic digestion, and how the hell does it work? Glad you asked!

The short version is that when wastes break down in the absence of air (whether it's those spoiled veggies you chucked in the landfill, or the leftover butcher's scraps that went in the garbage) they produce methane. If you've ever seen the fire stacks on landfills that occasionally burst into flames, that's the landfill burning off this methane so it doesn't build up in the landfill itself.

Rather than just letting all that methane escape up into the atmosphere where it contributes to all the other unwanted emissions we have going, anaerobic digestors essentially allow us to dump our unwanted materials into contained areas, separating the gas from the decomposing solids. As the video above shows, the methane is burned to drive turbines and create electricity, while the digested solids can now be re-used as nutrient-rich fertilizer. In short, it turns what was an unwanted waste product into a valuable source of fuel!

This Isn't a New Thing

By any stretch of the imagination.

Like basically every other "exciting new discovery" in the field of green technology, humanity has known about anaerobic digestion for centuries. Not only that, but we've been actively putting it to use in large-scale ways since ancient history.

According to Penn State, there's some anecdotal evidence that biogas from methane was used to heat baths in Assyria as far back as the 10th century B.C. It was used by Persia in the 1500s. European scientists did more research on the production of biogas in the 1700s, and in 1895 a facility in England captured gases from a specifically-designed sewage treatment facility in Exeter as fuel to light the street lamps. Anaerobic digestion was used extensively during WWII, and there are thousands of facilities across Europe that recycle this material. Not only that, but anaerobic digesters at breweries, dairy farms, cattle ranches, and other operations that produce a large amount of biomass waste have been in operation since before the new millennium.

With that said, our understanding of how to get the best possible results out of these digestors, and how to use them safely and effectively, has increased. And it isn't a major controversy to say that if we really went whole hog on this technology it would be a stride in trying to avoid major climate change.

Just How Big of a Stride Are We Talking?

Anaerobic digesters turn our trash into resources, plain and simple. And given the sheer amount of waste we have just laying around that could be put to use right now, that could lead to some serious recuperation of energy, and reduction in emissions. So, let's take a look at some numbers from the Environmental and Energy Studies Institute, shall we?

Let's start with food waste. Roughly a third of the food we grow in the world winds up in the trash, and in 2010 in America that was about 66.5 million tons of food waste generated throughout the year. Not an insignificant amount. Some quick math says that's about 182,191 tons of food waste produced every day, just in America.

So what could that do if it was processed into anaerobic digestors?

Well, according to the numbers, these digestors can produce enough power for 800 to 1,400 homes off of 100 tons of food waste every day. If we use the low-end estimate, that's enough energy to power roughly 1.5 million homes, just by redirecting those rotten apples, restaurant scraps, unwanted farm fruits, and all the other food slops we have just rotting in our landfills.

For numbers sake, that's roughly 16.5 million megawatt hours per year. Give or take.

But wait, there's more!

While we have a lot of food waste laying around, that is only a single category digestors can use to create energy with. If we add in livestock waste (from all those cows, goats, sheep, and other animals we need to create all that food waste), we could generate another 13 million megawatt hours of energy every year. If you were to add in the methane generated by our wastewater treatment facilities (where all the human poop goes), along with crop wastes, dog and cat wastes, trimmings from lawns, forests, etc. that's even more potential energy!

However, there is another facet of large-scale use of anaerobic digestion. Because in addition to creating energy, it eliminates this waste from our stream. This means that the captured methane is stored, rather than just being released into the atmosphere, which cuts down on environmental damage. It doesn't eliminate it entirely, as there will still be emissions when the methane is used, but it reduces the harm significantly according to numbers from the EPA. Not only that, but if this energy replaces fossil fuels like coal power, mined natural gas, and other sources, that eliminates them from the overall emission equation, reducing overall emissions even more.

When you add in that these facilities use a ready source of fuel that we generate, and that they're renewable (as long as we keep generating food waste, raising cattle, and pooping, at any rate), they are a massive advantage that should definitely be expanded on if we are going to take serious steps to combat climate change.

There is No Silver Bullet

As environmentalists the world over say, there is no silver bullet. While large-scale change makes a different, and it can throw on the brakes when it comes to climate change, it's important to keep the scale of the sheer challenge in mind.

If we combined food waste and livestock waste together, and we used all of it to generate power, that would be roughly 30 million megawatt hours per year. More if we were to use all of our waste water treatment facilities in the U.S. to turn our human waste into power. Even then, we would likely generate less than 50 million megawatt hours of energy per year. Coal-fired plants generated 774 million megawatt hours of energy in 2020, and that was with the decline in overall coal usage. According to the National Renewable Energy Laboratory, if we were to utilize all of the potential biogas solutions we have to their fullest, it would be enough to displace about 5 percent of current natural gas usage. That's still a colossal amount of generated energy, probably enough to power several cities, but it is only a fraction of the total demand across America.

Numbers can be discouraging, but they're the only metric we have.

Now, does that mean we shouldn't diversify our energy? Absolutely not! Because replacing those 30 million+ megawatt hours with renewable energy that cuts down on our emissions and massively reduces our waste is still a good thing. However, it's just a step, not the whole damn journey!

Expansion of anaerobic digestion will need to be combined with solar and wind expansion, several steps to reduce the amount of energy we waste every year, cleaning up what our industries are allowed to generate, and a thousand other things. No one program, no matter how ambitious, is going to be the answer to this quagmire we've spent decades getting ourselves into as a species... but that doesn't mean we shouldn't do everything we can to fix it.

Would You Like More?

Green energy has been something of a passion of mine for years now, and I'd like to keep this series going. If you want to see more coverage on topics like this, toss me a like, and share this article on your social media pages to help spread the word!

And if you'd like more, definitely take a moment to check out Can Large-Scale Telecommuting Save The Environment?, along with the rest of my full Vocal archive! Every view helps keep me going!


Neal Litherland

Neal Litherland is an author, freelance blogger, and RPG designer. A regular on the Chicago convention circuit, he works in a variety of genres.

Twitter: @nlitherl



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