Naming a problem does not solve
it. “Carbon sequestration” sounds like
somebody has figured it out, but it is just another way of saying “hide it
somehow.” At best, it’s avoiding dealing with the problem of CO2 emissions,
pretending that they are gone because they are out of sight.
Once carbon dioxide has been
captured out of flue gas, then what?
Assume you can capture all of the carbon dioxide emitted by a 250-MW
coal-fired electric power plant. You
have 1.7 million metric tons. The
density of carbon dioxide gas is 1.98 kg/m³ at STP so let’s say that each
metric ton of CO2 at sea level pressure on a warm day occupies 554 cubic
meters. The 1.7 million metric tons make
a volume of 941 million cubic meters to dispose of. Let’s round it off to an even billion. Just one plant in one year produces a waste
stream of 1 billion m3.
You can see immediately from
this volume that the disposal problem (“carbon sequestration”) is a very big
one. Where do you find space for hiding
a billion cubic meters of CO2, and how can you be sure it won’t leak from where
you put it?
A useful comparison is nuclear
waste disposal. If all of the nuclear
waste from the past 40 years in America were concentrated in one place, it would
cover a football field, with the end zones, 15 feet deep. Even this small volume cannot find a
home. The citizens of Nevada have
declined the honor of storing it at Yucca Mountain, and it looks unlikely that
the federal government can force them to accept it. Hosting a carbon dump will probably prove
similarly unpopular. Leaking from the
carbon dump can be deadly to people above it.
When the pressure is increased to cram more carbon dioxide into the
dump, the danger of leaks increases. Even if a dumpsite is available,
there must be a way to get 1.7 million tons there securely.
The IPCC Report on Carbon Dioxide Capture and Storage takes a comprehensive look at the available options and concludes that more research is needed, that the regulatory risks have not been settled, and that there is a significant cost involved in any attempt at a solution. It seems clear that simply relying on
“sequestration” is not a reasonable option, and we should look to ways of transforming CO2 into something else, or even
recycling the carbon as fuel.
Unfortunately the problem of carbon dioxide is growing rapidly, and the need for an effective solution is greater every day. According to the Earth Policy Institute, 8.38 billion tons of carbon dioxide were emitted worldwide in 2006, an increase of 20% in just six years.
A better approach to the problem is to convert the carbon dioxide into something useful. Hybrid Power can use renewable energy to take care of CO2 emissions, using Vorsana's gas separation and gas cracking technology.