222
The 1990 amendment to the Clean Air Act required cutting sulfur emissions in
half, and solutions were needed. A process called flue gas desulfurization was
developed to prevent the sulfur dioxide from escaping into the atmosphere. This
simple and effective technique adds limestone (CaCO 3 ) to the coal prior to combustion. When the coal is burned at high temperature, the limestone breaks down thermally into calcium oxide and carbon dioxide. The calcium oxide binds with sulfur
dioxide to create gypsum (CaSO 4 ). Gypsum is a solid mineral that falls out of the
stack gases and is recovered. The process is effective at removing 95% of the sulfur
dioxide that would previously have been vented in the flue gas. Some coal-fired
powerplants have drywall factories located nearby that use the recovered gypsum to
make building materials.
Perhaps an equally simple solution exists for the capture of CO 2 from stack gases
and vehicle exhaust pipes. As described previously, both calcium hydroxide and
sodium hydroxide are known to react with CO 2 to create solid mineral phases.
Perhaps other chemicals do as well. Additional studies are needed in this area to
explore possible options.
Various technologies for removing CO 2 from exhaust gases using CCS or directly
from the atmosphere using DAC have been presented by a number of researchers
(e.g Stolaroff et al. 2008), but with little consideration given to economics or policy.
The technology is important for carbon capture, but policies must be implemented
to make it required and to address the economics of the added cost. The absence of
a policy has made efforts to implement widespread CCS extremely difficult.
Trying to force CCS to pay for itself in an unregulated market economy is a certain failure. Claiming that CO 2 is a valuable resource rather than a waste product
falls flat, because there are simply no demands for this gas that are not already being
met. Counting on the economics of CO 2 sales to drive the widespread adoption of
CCS is a fantasy. Even though this strategy has worked to some degree for the sulfur
compounds from coal combustion in that a use has been found for the gypsum, it is
important to remember that the policy requirements of the 1990 Clean Air Act
amendments were the driving force behind the development of flue gas desulfurization, not the economics of drywall manufacturing.
CCS can be an energy transition technology that will allow the continued use of
fossil fuels without adding GHG emissions to the atmosphere. If implemented properly and widely, CCS will buy some time for the electrical power, automotive, and
manufacturing industries to develop alternatives to burning coal, oil, and/or natural
gas. But until some way is found to level out the economic costs, CCS will not be
widely used.
Carbon Tax The final component for the transition to sustainable energy and a
stable climate is policy. Congress can always pass laws simply requiring that fossil
fuel combustion products be kept out of the atmosphere, but these can be politically
difficult to get in place as well as challenging to track and enforce. A better method
for controlling GHG emissions might consist of both taxes and tax breaks to steer
industry and individuals away from emitting carbon dioxide and encourage them to
either use CCS or non-carbon energy technologies.
11 Balancing Energy, Environment, and Economics
The 1990 amendment to the Clean Air Act required cutting sulfur emissions in
half, and solutions were needed. A process called flue gas desulfurization was
developed to prevent the sulfur dioxide from escaping into the atmosphere. This
simple and effective technique adds limestone (CaCO 3 ) to the coal prior to combustion. When the coal is burned at high temperature, the limestone breaks down thermally into calcium oxide and carbon dioxide. The calcium oxide binds with sulfur
dioxide to create gypsum (CaSO 4 ). Gypsum is a solid mineral that falls out of the
stack gases and is recovered. The process is effective at removing 95% of the sulfur
dioxide that would previously have been vented in the flue gas. Some coal-fired
powerplants have drywall factories located nearby that use the recovered gypsum to
make building materials.
Perhaps an equally simple solution exists for the capture of CO 2 from stack gases
and vehicle exhaust pipes. As described previously, both calcium hydroxide and
sodium hydroxide are known to react with CO 2 to create solid mineral phases.
Perhaps other chemicals do as well. Additional studies are needed in this area to
explore possible options.
Various technologies for removing CO 2 from exhaust gases using CCS or directly
from the atmosphere using DAC have been presented by a number of researchers
(e.g Stolaroff et al. 2008), but with little consideration given to economics or policy.
The technology is important for carbon capture, but policies must be implemented
to make it required and to address the economics of the added cost. The absence of
a policy has made efforts to implement widespread CCS extremely difficult.
Trying to force CCS to pay for itself in an unregulated market economy is a certain failure. Claiming that CO 2 is a valuable resource rather than a waste product
falls flat, because there are simply no demands for this gas that are not already being
met. Counting on the economics of CO 2 sales to drive the widespread adoption of
CCS is a fantasy. Even though this strategy has worked to some degree for the sulfur
compounds from coal combustion in that a use has been found for the gypsum, it is
important to remember that the policy requirements of the 1990 Clean Air Act
amendments were the driving force behind the development of flue gas desulfurization, not the economics of drywall manufacturing.
CCS can be an energy transition technology that will allow the continued use of
fossil fuels without adding GHG emissions to the atmosphere. If implemented properly and widely, CCS will buy some time for the electrical power, automotive, and
manufacturing industries to develop alternatives to burning coal, oil, and/or natural
gas. But until some way is found to level out the economic costs, CCS will not be
widely used.
Carbon Tax The final component for the transition to sustainable energy and a
stable climate is policy. Congress can always pass laws simply requiring that fossil
fuel combustion products be kept out of the atmosphere, but these can be politically
difficult to get in place as well as challenging to track and enforce. A better method
for controlling GHG emissions might consist of both taxes and tax breaks to steer
industry and individuals away from emitting carbon dioxide and encourage them to
either use CCS or non-carbon energy technologies.
11 Balancing Energy, Environment, and Economics