The "Air Pollution Management" Newsletter

June 2008
No. 362

Co-firing, Ethanol, Hydrochloric Acid

Changes to existing coal-fired plants could cause net reductions of CO2 by 35 percent. Replacement of these plants with new super critical boilers and the incorporation of other technology could make a net 55 percent reduction.

Net CO2 emissions with incremental technology additions including credits as a percent of an existing coal-fired boiler without changes are shown in Figure 7.





Base CO2 Emissions %


Efficiency improvements


Co-firing biomass


Waste heat for ethanol


Hydrochloric acid by product


Reduction from the combination %

Existing Coal-fired boiler













New ultra super critical coal-fired boiler



30% is already achieved










These are net reductions and take into account the CO2 emissions from the whole process of oil exploration through refining and gasoline transportation as opposed to ethanol production using the coal plant waste heat. The elimination of chlor alkali plants and their resultant CO2 contribution is included.

The CO2 reduction costs of either retrofitting existing coal plants or the construction of new super critical plants is very low compared to renewable energy alternatives or to CO2 capture and sequestration. Furthermore all the technology is in place.

These opportunities to reduce CO2 net generation from coal by 55 percent by replacing an old coal plant with a super critical boiler making ethanol and hydrochloric acid is very promising. It could result in as much as 200,000 MW of new coal capacity while reducing net CO2 emissions. So the net addition of new coal plants would be 530,000 MW under this scenario (replacement of 330,000 MW of existing plants and addition of 200,000 MW of new plants).

Great River is moving ahead with the 66 percent efficient Spiritwood plant. It is already operating the Coal Creek plant which supplies all the heat needed at Blue Flint Ethanol. Others are sure to follow.

The odds are less than one to nine that the industry will take full advantage of this opportunity, but this would still result in 60,000 MW of new capacity absent other events. The odds are that this will cause a 20 percent increase in coal capacity absent other drivers, so we have estimated the odds at two to one rather than a greater certainty that at least a 60,000 MW addition will be achieved. Based on the rush to new coal plants in Europe this is a very conservative estimate.

High Electricity Demand

The DOE reference case showing 100 GW of new coal-fired capacity including 29 GW of coal gasification and 4 GW equivalent of coal-to-liquids by 2030 is based on demand increase as follows:

·         Residential            1.0%/yr

·         Commercial          1.7%/yr

·         Industrial                0.l%/yr

The basis of this forecast is shown at

We believe the odds are six to one or greater that demand will meet or exceed the DOE base case.

Renewables Supply Limits

The problems with renewables were reviewed above under “Renewable Energy Costs Fall to Less than 200 Percent of Coal”. There is presently a shortage of wind turbines and no sign that renewables can compete for base load generation in the next 15 years

Nuclear Supply Limits

This is covered above under the negative “Nuclear Impact is Major.”


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