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A simpleton might ask, “If CO2 in our atmosphere is causing climate change, why don’t we
just put it underground?” You idiot, you’re a genius.
Hi everybody, Julian here for DNews. There are a lot of options for curbing CO2 production
on the table, with my personal favorite being not making any more of it. But as it stands
right now, we’re still very dependent on energy production methods that pump billions
of tons of it into the atmosphere annually.
Recently I made a DNews episode on a method natural gas plants can use to condense their
CO2, which makes it easier to pressurize it and store it underground. But I wanted to
follow up with a look at if that’s really a viable option.
Right now the idea is being put into action in Decatur, Illinois by Archer Daniels Midland.
They produce over 2,700 tons of CO2 daily as a byproduct of turning corn into ethanol.
For the last 3 years they’ve been pressurizing a third of that CO2 and pumping it into sandstone
2,100 meters below the surface.
The Carbon Dioxide is heated to 35 degrees celsius and pressurized to 9.8 megapascals.
At that temperature and pressure the molecules don’t act like a gas, but they don’t act
like a liquid either. They’re whats called a supercritical fluid, with properties of
both. It can be pumped through a pipe, but when it reaches the sandstone sediment deep
underground, it effuses through the pores like a gas. This property lets ADM pump 1,100
liters of Carbon Dioxide underground a minute. Of course eventually the sandstone deposit
underground will run out of pore space, but right now it’s estimated this particular
deposit can store centuries of emissions from the upper midwest. According to the US Geological
Survey, there are enough sandstone sites around the US to store American emissions for 500
years.
Great, let’s start drillin’ and fillin’ right? Not so fast, there are possible downsides.
Recently headlines were made when studies showed conclusively that earthquakes in Ohio
were becoming more frequent because of hydraulic fracturing. Fracking isn’t quite the same
as this method of carbon capture and storage, Fracking involves pumping water, sand, and
other chemicals underground to break rocks and release natural gas. Scientists believe
the water may be causing slippages in hidden faults, or providing just enough pressure
to induce seismic activity.
With this in mind the USGS is monitoring seismic activity by the Decatur site and so far it
looks like the storage isn’t having negative effects topside, so ADM is planning on scaling
up and pumping all their CO2 underground. Even if it works flawlessly here detractors
aren’t certain other sites won’t be near hidden faults, and we’re going to need a
lot more places to put the carbon dioxide if this is going to put a dent in how much
we make. Thousands more wells like the one in Decatur in fact. So far ADM has pumped
about a million tons underground but the US emits over 5 billion tons of it annually.
Plus if the CO2 will find or open cracks in the bedrock above it and seep back out again,
the whole exercise is moot.
It’s not an immediate fix to the problem, and if it ends up causing more damage than
it prevents the plug may be pulled on this form of carbon storage entirely. So for now
it looks like the best solution is to reduce emissions where possible, work towards carbon-neutral
energy production, and steadily introduce carbon capture and storage to cut down on
how much we emit now.
CO2 isn’t just messing with the environment globally, it can also screw up your brain
if you’re stuck in a crowded room. Matt’s video explains over here.
Have you been affected by earthquakes either natural or man-made? If you’ve got a story
or want us to look into it, share with us in the comments and I’ll see you next time
on DNews