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.