Lecture 12: Fossil Fuels - Environmental Impacts PDF

Lecture 12 (Ch 6) Fossil Fuels- Environmental Impacts ENV-474 Energy and Sustainability Energy, Environment, and Climate Copyright © W.W...

Lecture 12 (Ch 6) Fossil Fuels- Environmental Impacts ENV-474 Energy and Sustainability Energy, Environment, and Climate Copyright © W.W. Norton & Company 2012 Environmental impacts of fossil fuels are many! In addition to climate change – environmental impacts from fossil fuels include the extraction-, transportation-, processing- and burning phase. All these 4 phases contribute in different ways (and to various degrees) to environmental degradation - depending on the type of fossil fuel and method used.  Envrionmental impacts of fossil fuels are many! Coal strip mining Coal trains Coal washing Flue gasses from powerplant 1. Extraction phase 2. Transportation phase 3. Processing phase 4. Burning phase Oil drilling Oil tanker Oil refinery Exhaust gasses from traffic Environmental impacts of fossil fuels are many! Extraction of coal – destruct the landscape and can contribute to acid mine drainage Coal mines can catch fire and burn- 10- 100s of years, releasing large amounts of CO2 and air pollution. Extraction of oil – can impact the marine environment - especially if there is a leak from the oil/gas well. Also flaring of gasses from the oil platforms will contribute to CO2 emissions, and air pollution Transportation of especially oil has had very detrimental effects over the years, but also the emissions from just the transport (both sea and land) will contribute to CO2 emissions and air pollution  Coal industry – huge environmental footprint! Examples of environmental impacts from coal industry: 1.Strip mining: has impacts on land and surroundings by severely altering the landscape, which reduces the value of the natural environment in the surrounding land. Mine tailings and dust from mining operation. https://www.youtube.com/watch?v=ynN39sfqT8w 2.Coal washing: coal needs to be “washed” with water and chemicals to reduce the impurities before it can be burned in a power plant. Coal washing is a water-intensive process: typically, washing one ton of coal consumes about 45 m3 liters of water. (=45 000 m3 water per day to sustain 1GW powerplant). Dirty water run-off containing coal impurities Surface mining – “scouring” the landscape Coal industry – huge environmental footprint! Landscape Coal washing alteration and (water use and mine tailings pollution) Coal industry – huge environmental footprint! Examples of environmental impacts from coal industry: 3. Burning of coal – causes air pollution (SOx, NOx, heavy metals) and climate change (high CO2 emissions) 4. Cooling of water plant – thermal pollution of rivers, lakes, oceans 5. Coal waste – Coal and coal waste products release approximately 20 toxic- release chemicals, including heavy metals which are dangerous if released into the environment. Ash from power plants stored in coal ash basins/impoundments (dams). Coal is a cheap way of producing electricity, but if you include the environmental costs, the cost of using coal is very high! Coal industry – huge environmental footprint! Air pollution & Coal waste climate change (toxic ash) https://www.youtube.com/watch?v=FdeXb8IxJCM  Acid Mine Drainage Run-off released at certain types of mines can cause local increases in the acidity (pH "Yellowboy" + Sulfuric Acid. Some or all of this iron can precipitate to form the red, orange, or yellow sediments (yellowboy) on the streambed.  Underground coal fires in abandoned coal mines can burn for 10s-100s years! Significant contributions to CO2 emissions globally https://www.youtube.com/watch?v=fvoCzunex3I Conventional oil and gas extraction On April 20, 2010, an explosion occurred on the Deepwater Horizon drilling platform in the Gulf of Mexico Resulted in oil spewing into the ocean for 3 months before the well could be closed. 5 million barrels of oil leaked into the Gulf of Mexico. The largest oil spill ever (65 billion dollars in fines) had severe consequences for marine life due to the oil spill, and the chemicals used to disperse the oil. Still 10 yrs after the accident, the ecosystem has not recovered fully, and oil clumps can still be found floating ashore on beaches.  Conventional oil and gas extraction Conventional oil drilling rigg Deep-water horizon accident 2010 https://www.youtube.com/watch?v=7RJGXDXfYBI “Unconvention al” oil extraction  “Unconventional” oil extraction Shale oil: Kerogen containing rock in shallow deposits Oil produced by crushing and heating (300- 480oC) the rock 15-30 gallons oil/ton shale Large impacts on environment: pollution and altering of landscape, very energy intensive, CO2 emissions, air and water pollution “Unconventional” oil extraction Tar sand: Shallow deposits of sand containing highly viscous oil (bitumen) Oil extracted with steam/hot water/chemicals Canada: huge deposits Environmental impacts – altering the landscape, energy intensive, CO2 emissions, air- and water pollution  Unconventional gas extraction (hydraulic ‘fracking’) Environmental concerns: Pollution by “extraction chemicals” into groundwater Wastewater – large amounts of water is used in the process Release of methane to surrounding geology – leak into ground water Injection of large amounts of water and sand with very high pressure (or use of explosives) in shale rock – to decrease the porosity of the rock -> release the gas Chemical additives (e.g. diesel, benzene) to lubricate extraction process https://www.youtube.com/watch?v=Tudal_4x4F0  Transportation of fossil fuel: Oil shipping Oil is one of the most transported commodities worldwide. Transported with large oil tankers on the water and in pipelines on land. Risk for accidents, leaks => major Oil spills Effect of oil spills in the ocean Oil is lighter than water, so it floats on surface Lighter oils (e.g. gasoline or diesel), toxic to animal/plant life, explosive, volatile – (evaporates) Heavier oil (crude oil), lower toxicity, less explosive, stay longer in the marine environment, sticky (smothers animal life) Ingestion, skin/eye irritation, smothered or poisoned by oil slick, feathered animals can’t keep body temperature. Prevent sunlight into the ocean (affect productivity and photosynthesizing organisms  Effect of oil spills in the ocean https://www.youtube.com/watch?v=Gtwcb5qF6SQ ‘Hot-spots’ for oil-spills 4.5 million tonnes of oil has been spilled in the ocean over the last 50 yrs. The biggest was during the Iraq war. Almost 10000 accidents with oil spills over the last 50 yrs.  Worst oil spills in history Deep-Water Horizon in Exxon-Valdez oil tanker in First Gulf war oil spill in Gulf of Mexico 2010 Alaska 1989 Iraq, Arabian Gulf 1991 >200 million gallons 11 million gallons 60-250 million gallons https://www.youtube.com/watch?v=yz-iVTk54kw Decrease in the number of oil spills Figure 6.19  Improved oil tankers – must be “double- hulled” and have separate ballast water tanks Refineries are hazardous and polluting industry Pollution: Air pollution – toxic gasses, VOC’s (benzene, xylene etc) Greenhouse gasses – Climate change Wastewater – production water, cleaning effluents Oil/petroleum spills Explosions: Chemicals (petrochemicals) Texas City Refinery 2005 – 15 dead, 170 injured Gasses (methane, hydrogen) Global oil refineries and their emissions Environmental impacts from burning coal and oil Environmental consequences: Air pollutants Climate change Acid rain Public Health Impacts Thermal pollution  Thermal Pollution from Power Plant Cooling Cooling water from power plant is released back to water body Warmer water can hold less oxygen – can lead to low dissolved oxygen conditions. Fish mortality (& coral mortality in the Gulf) Altered ecosystems due to changes in environmental conditions (different animals and plants has different thermal tolerance) Thermal Pollution from Power Plant Cooling Why coal is worse to burn than oil and gas: Environmental impact