| dc.description.abstract |
<p>The changes to the environment caused by anthropogenic climate change pose major
challenges for energy production in the next century. Carbon Capture and Storage (CCS)
is a group of technologies that would permit the continued use of carbon-intense fuels
such as coal for energy production while avoiding further impact on the global climate
system. The mechanism most often proposed for storage is injection of CO2 below the
surface of the Earth in geological media, with the most promising option for CO2 reservoirs
being deep saline aquifers (DSA's). Unlike oil and gas reservoirs, deep saline aquifers
are poorly characterized and the variability in their properties is large enough to
have a high impact on the overall physical and economic viability of CCS. Storage
in saline aquifers is likely to be a very high-capacity resource, but its economic
viability is almost unknown. We consider the impact of geological variability on
the total viability of the CO2 storage system from several perspectives. First, we
examine the theoretical range of costs of storage by coupling a physical and economic
model of CO2 storage with a range of possible geological settings. With the relevant
properties of rock extending over several orders of magnitude, it is not surprising
that we find costs and storage potential ranging over several orders of magnitude.
Second, we use georeferenced data to evaluate the spatial distribution of cost and
capacity. When paired together to build a marginal abatement cost curve (MACC), this
cost and capacity data indicates that low cost and high capacity are collocated; storage
in these promising areas is likely to be quite viable but may not be available to
all CO2 sources. However, when we continue to explore the impact of geological variability
on realistic, commercial-scale site sizes by invoking capacity and pressure management
constraints, we find that the distribution costs and footprints of these sites may
be prohibitively high. The combination of issues with onshore storage in geological
media leads us to begin to evaluate offshore storage potential. By considering the
temperature and pressure regimes at the seafloor, we locate and quantify marine strata
that has "self-sealing" properties, a storage option that we find is plentiful off
the coasts of the United States. We conclude that further research into transport
optimization that takes into account the true variation in geological media is necessary
to determine the distribution of costs for carbon capture and storage to permit the
full evaluation of CCS as a mitigation option.</p>
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