Environmental Engineering Reference
In-Depth Information
dioxide is compressed and stored in geologic formations, such as oil and gas
reservoirs, its density is close to that of some crude oils, resulting in buoyant
forces that tend to drive carbon dioxide upwards. It is unknown whether carbon
dioxide will remain safely sequestered if pressure, temperature, or other
conditions change. According to international climate change experts, leakages
could significantly affect climate change or contaminate groundwater. Moreover,
given the long-term nature of carbon dioxide capture and sequestration, storage
sites may require monitoring for very long periods of time—possibly for
“eternity,” according to one DOE official.
New coal gasification plants also face the high costs associated with
employing advanced energy technologies, such as IGCC and carbon dioxide
capture and sequestration systems. In particular, IGCC plants are 20 percent more
expensive—about $100 million more—than pulverized coal plants that use
currently available technology, according to International Energy Agency, DOE,
and industry officials. Moreover, carbon dioxide capture and sequestration
technologies will further increase an IGCC plant's costs because capturing and
sequestering carbon dioxide increases fuel consumption by as much as 25 percent.
According to international climate change experts, an IGCC plant that employs
carbon dioxide capture and sequestration technologies could increase the cost of
electricity per kilowatt hour from 21 to 78 percent, depending on plant design, the
cost of fuel, and the storage site characteristics.[26]
In addition to technological and cost barriers, the uncertainties surrounding
new coal-gasification technologies create substantial investment risks that threaten
to hinder development. Despite the greater efficiency, reduced emissions, and the
ability to capture carbon dioxide, only four coal-based IGCC power plants
currently operate worldwide. The unproven nature of IGCC technology creates
uncertainty and reluctance among industry to invest in building a new coal-based
IGCC power plant, particularly given the additional cost, according to DOE and
industry officials. Furthermore, international climate change forecasting models
predict that carbon dioxide capture and sequestration systems are unlikely to be
deployed on a large scale without explicit government regulations that
substantially limit greenhouse gas emissions to the atmosphere. In light of such
technological uncertainties, industry officials noted that cost-sharing initiatives
with DOE will continue to be an important factor in encouraging the
demonstration and deployment of IGCC plants.
