Coal-fired Power Plants

What is Coal Exactly?

• A readily combustible brownish-black sedimentary rock
• A “fossil fuel” – compressed remains of plant and/or animal life
• Composed primarily of carbon and hydrogen, along with small quantities of other elements, primarily sulfur

Electricity Production

• Burning of coal (or any fossil fuel) produces CO2 and water vapor, and releases heat
• Heat is used to turn turbines to generate electricity
• Process is only 35% efficient
• The primary type of coal-fired power plant in the world today is a pulverized coal combustion system

A Typical Pulverized Coal Combustion Plant: Image

What's in that cloud?

• Problem – release of CO2, a greenhouse gas
  • Coal is the largest contributor to human-made increase in CO2
  • In 2004, U.S. coal-fired power plants produced more CO2 than was produced by all sources in Africa and South and Central America combined
• Also releases other chemicals/compounds
  • Fine Particulates
  • NOx
  • Mercury
  • SO2 (acid rain)
  • Radioactive materials (Uranium, Thorium, etc.)

Statistics

• 97% of deadly fine particle soot and sulfur dioxide emissions;
• 92% of smog-forming nitrogen oxide emissions;
• 86% of emissions of carbon dioxide, the primary global warming pollutant
• Almost 100% of toxic mercury emissions

Health Impacts

• Fine particle pollution
• Particles are able to get deep into lungs and can enter bloodstream
• Exacerbates existing conditions such as asthma and heart and lung disease
• Triggers heart attack by causing irregular heartbeat
• 23,600 people are killed from this each year- more than drunk driving and homicide!
• Also has been linked to an increase in Sudden Infant Death Syndrome

So Why Use Coal?

• It’s Cheap!
  • US has a 245 year supply of coal reserves
  • These reserves contain more energy than the world’s oil reserves (The Saudi Arabia of Coal)
• States that use primarily coal fuel to produce electricity have the lowest electricity rates in the nation
• Existing infrastructure (power plants) are more cost-effective

US Coal Reserves: Map

A Case Study in Coal Use: California

• The U.S. is now the world leader in wind electricity generation.
• Currently produce over 20,000 MW
• 4.5 million homes

  Energy Source: Electricity	US Average	California Average
  Coal	50%	20%
  Natural Gas	19%	38%
  Nuclear	19%	15%
  Large Hydro	7%	17%
  Biomass	0.4%	2.1%
  Geothermal	0.4%	5.0%
  Wind	0.4%	1.5%
  Small Hydro	-	1.9%
  Solar	-	0.3%

So What Are the Options?

• “Fix” coal power
  • Make it “cleaner” – 2002 Clean Coal Power Initiative
• Find new sources of energy
  • New sources should be cost-comparable with coal to be feasible

Clean Coal

• Carbon Sequestration
  • Capture and store the carbon dioxide before it is released into the atmosphere
• Integrated Gasification Combined-Cycle (IGCC): Image
  • Breaks down and “cleans” coal prior to combustion
  • Added benefit of producing clean H2, which could be used in other applications

Is Clean Coal the Best Option?

• California Public Utilities Commission reports:
  • Clean coal – 17 cents per kilowatt hour
  • Utility-scale solar power – 12.7 cents per KWh
  • Wind power – 9 cents per KWh
• In the long run, “green” energy is more cost-effective than “clean” coal; however, “dirty” coal still cheapest
• So, what should be done? What do you think?