NEWS RELEASE                                   JANUARY 2009

Coal/Biomass Combination With CO₂ Capture Is Greener Than Renewables But Not Most Eco-Efficient

If a combination of coal and biomass provided the energy source for electricity and the CO₂ from the combustion was captured, there would be more carbon extracted from the atmosphere than returned to it.

The best global warming reducer would be a 100 percent biomass boiler with 90 percent CO₂ capture, but there is not enough biomass to generate the electricity the world needs.  However, a combination of coal and biomass would be sufficient.

In Europe coal-fired boilers are required to co-fire biomass.  Doosan Babcock has successfully supplied systems that fire pulverized coal with 20 percent biomass.  With Foster Wheeler circulating fluid bed technology, unlimited quantities of biomass can be mixed with coal.  The UK is growing and pelletizing straw to use as boiler fuel.  This biomass takes CO₂ out of the atmosphere as it grows.  If the CO₂ it releases when combusted is captured and sequestered, then this process is a very effective CO₂ reducer.

There are other advantages of the coal/biomass combination.  The waste steam can be effectively used by industry and in the case of New York City for heating and cooling of buildings.  Great Rivers Energy is using the waste steam to make ethanol.  The flyash which is produced replaces cement and saves one ton of CO₂ for every ton of flyash used.  Other byproducts are gypsum for wallboard, sulfuric acid, sulfur, ammonium sulfate fertilizer, calcium chloride, and hydrochloric acid.

Coal/biomass fired power plants with CO₂ capture will be very clean.  Pollutants such as NO_x and SO_x have to be reduced to below 10 ppm prior to entering the CO₂ scrubber.  These trace amounts are further captured in the CO₂ scrubber solution or sequestered.  Alstom and other suppliers are building full scale CO₂ capture systems.

Coal can be clean in all respects.  The newest coal-fired power plants use 30 percent less coal than the older designs.  Enel contracted with Aquatech to provide zero liquid discharge technology for the wastewater at three of its plants in Italy.  The TVA ash pond dam breakage which made headlines recently is representative of old technology, not the new design where the ash is a useful product.

The coal/biomass combination with CO₂ capture is clearly the best option from the perspective of greenhouse gases.  With this technology universally applied, the CO₂ in the atmosphere would steadily drop from the present level of 385 ppm.

The question is how fast could this technology be implemented in the U.S and at what cost?  The short answer is that there is not enough biomass now and a program to create it will take time and money. CO₂ capture and sequestration is presently costly but may become less so with developments underway.

Greenhouse gases and environmental pollution are only part of the equation.  The investment in coal/biomass, solar, wind and other alternative energies has to take into account the total eco-efficiency considerations.  The environmental burden has to be weighed against the cost.

McIlvaine has created a universal environmental burden index which can factor with costs to determine the best options.  

Coal-fired power plants emit 2.1 lbs of CO₂/kWh.  The total environmental burden from coal-fired power plants including CO₂, NO_x, particulate, toxics, and SO₂ is 5.46 equivalent lbs/kW-hr.  

New coal-fired power plants would cost $2500/kW to build with a useful life of 25 years.  The depreciation would be $ .0125/kWh.  If the plants were only operated for 15 years, the depreciation would rise to only $0.02/kWh.  Hence, even if new coal-fired plants were operated for less than their useful life, they could be very cost effective.

Environmental Burden Reduction Costs

Solar, wind, nuclear and coal-fired power plants with carbon sequestration will be more costly than super-critical coal-fired power plants, if widely applied.

New ultra-super-critical plants with a 25 year life are obviously the most eco-efficient.  Even if these plants are only operated for 15 years, they are still 22 percent more eco-efficient than retrofitting the old coal plants.  New coal plants with carbon sequestration and biomass co-firing provide the most environmental burden reduction but at more than twice the cost of electricity.

Existing coal-fired power plants in the U.S. can be replaced with ultra-supercritical carbon-ready power plants with biomass co-firing.  The advantages are:

·         $600 billion economic stimulus with no increase in electricity cost,

·         30% reduction in coal consumption,

·         More than 30% CO₂ and 70% total environmental burden reduction,

·         Meets the goal of 20% greenhouse gas reduction by 2020.

These plants would be carbon capture ready and could be fitted with co-firing and CO₂ capture at a later date.

Investment would be fully realized by 2038-44 and replaced by even newer technology to meet the 80 percent reduction of greenhouse gases in 2050.

More information on the McIlvaine eco-efficiency analysis and implications for energy choices are found at: 

http://www.mcilvainecompany.com/brochures/latest%20news/replace_coal_plants/Replace_old_coal_plants.pdf .