Wednesday, 22 June 2016

Getting Biblical on CO2: How to turn your enemies to stone

Wouldn’t it be nice to have the power to turn your enemies into stone? It sounds like something out of the Old Testament or Greek myth, but it’s pretty darn effective. Unless they are careening down a hillside, at whose base you happen to be sitting, stones are relatively inert and harmless. Sadly, despite what religious texts or Tolkien books tell us, this probably isn’t a realistic strategy in the face of conflict.
Happily, no one told that to a group of scientists working in Iceland, who last week published the results of their 4-year research on turning one of humanities greatest foes into a ready supply of paperweights.

You’d be hard pressed to find a more fitting place for an epic showdown than Iceland. Desolate volcanic landscapes mix with moody weather to make it seem like the end of the world is always close at hand. Unfortunately, the gravitas of the setting is somewhat undone by the enemy we are talking about: a colourless, odorless, tasteless gas that every animal of Earth exhales but humans have found a special proclivity for pumping into the air. You know it as carbon dioxide (CO2).

Oddly enough, Iceland is one of the last places you would expect to find people working on a solution to carbon emissions. This isolated outpost of humanity in the North Atlantic gets virtually all of its power from geothermal sources. That is, the island is one big volcano, and so, they use its heat to keep the lights burning. This approach eliminates something like 95% of CO2 emissions associated with electricity production, but apparently that isn’t good enough for Icelandic scientists.

Wanting to inch a little closer to that zero-carbon goal, researchers at Hellisheidi power plant, near Reykjavik, decided to take some of their geothermal power plant’s paltry CO2 emissions and test an approach to neutralizing them; many people thought that was ridiculously impractical - ”that” being to pump the CO2 emissions deep into the ground and wait for them to turn to stone.

As you can imagine, this is a desirable way to fight climate change. The biggest challenge with carbon emissions is that gases are masterful escape artists. Put them into any container with even the slightest breach and they will soon be out mixing in the atmosphere like debutants at a cocktail party. Stone, by contrast, just tends to sit there and not do anything, like an awkward college freshman at their first frat party.

The science behind this idea is actually fairly straightforward. We have long known that when a type of rock called basalt is exposed to CO2 and a little water, the carbon will precipitate (solidify). The problem, like all things in geology, is a matter of time. In the type of uncontrolled field setting the Icelandic team was dealing with, ambitious estimates assume you would need eight years before a significant amount of the carbon was locked up.

So imagine the surprise (and presumed embarrassment) on the face of naysayers when the team from Hellisheidi reported that the process began in just a few months and that, after 2 years, 95 to 98% of the carbon injected into the rocks has turned into chalky, lifeless carbonate minerals. The process so far has been relatively small scale, pumping about 5,000 tonnes of CO2 underground per year – equal to about 15 Americans annual CO2 emissions – but it is promising.

For one thing, basalt as a resource isn’t exactly rare. Places like the Pacific Northwest, South America, and other volcanically endowed landscapes are ripe with it. Better yet, most of the Earth’s crust, beneath the oceans, is basalt. The only thing safer than turning your enemy to stone, is then placing that stone a mile or so underwater.

The major challenge at this point is cost, which sits around $17 per tonne of CO2. This compares favourably with other methods of capturing carbon emissions (usually between $23 and $95 per tonne), but is still expensive when you want to deploy it on the roughly 40 billion tonnes of CO2 that humans put into the air every year.

Clearly, we have some work to do to figure out how to scale up this technology, and in the mean time, we all need to take a hint from Iceland and switch our energy systems to renewable sources like wind, solar, and geothermal power. But, even once we stop treating the atmosphere like a garbage dump, we’re going to need technology to clean up the mess we’ve already made. The Hellisheidi technology gets us one step closer.

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