Fossil Fuels Chapter 19

1. Natural Gas What it is: –Mixture of methane (50-90%), heavier hydrocarbons (ethane, propane, butane) and small amounts of H 2 S (highly toxic) Properties: –Highly flammable; transportation difficult. Done in pipelines –Cleanest burning fossil fuel Methane is dried, cleansed of H 2 S, pumped in low pressure lines nationally. Heavier gases are removed as liquefied petroleum gas (LPG) for use in rural areas.

Natural Gas Distribution

Hydraulic Fracturing How: –Pumping water & chemicals under high pressure underground to force natural gas/petroleum to surface Problems: –Possible groundwater contamination –CH 4 released –Release of Fracking Chemicals

How Long Will Natural Gas Last? At current consumption rate, factoring in undiscovered reserves, approximately 125 years. Including unconventional sources, years

2. Coal What is it: –Solid fuel formed from plant matter during Carboniferous period, million years ago. C content increases, water content decreases over time Ranked according to energy content

Type Energy Content (megajoules/kg) Location in US 1.Anthracite30-34PA 2.Bituminous23-34Appalachia, Midwest, West 3.Subbituminous16-23West 4.Lignite13-16Gulf Coast, No. Great Plains

Half is acquired through Strip-Mining (Surface Mining) Acid Mine Drainage: rainfall reacts with exposed rock, reacts with sulfides, produces sulfuric acid. Processed to remove much sulfur before burning Uses of Coal: –converted into synthetic oil or gas. –Mostly used by power plants to create electricity (60% of electricity produced). –Transported by train and coal slurry pipelines (uses more water).

Open Pit Mining: digging at the surface to extract ore

Coal Surface Mining in Wyoming

Coal Mine in India

Pollution & Coal Burning releases mercury into env. Takes a great deal of water; expensive, heavy environmental impact Production of NOx and SOx Particulate Ash Treatment--Scrubbing –calcium carbonate-rich materials are injected into the gases produced from burning coal, producing hydrated calcium sulfite as sludge. –Disposal issues.

How Long Will Coal Last? At current consumption, 225 years. If usage rises 2%/yr, 65 years. Believed to be unidentified reserves projected to last 900 years.

3. OIL! Petroleum (crude oil): –thick liquid consisting of hundreds of combustible hydrocarbons. Impurities –sulfur, oxygen, nitrogen & other impurities. Formation –decomposition of organic matter (mostly plant) –extreme pressures & temperatures –millions of years Usually dispersed throughout pores in rocks.

Oil Recover: 3 Stage Process Primary: –Drilling a well, then remove oil that flows into the well. Secondary: –Pumping water under high pressure into a nearby well, forcing oil out, pump up to surface, – remove water from oil and reuse the water for recovery. Tertiary: –Use of superheated steam, CO 2 or detergent to dissolve oil, then removed from that. –Large amounts of energy needed (~1/3 barrel for every barrel produced) Production clip

Fractional Distillation Separating the components that make up crude oil. Uses boiling points of the various fractions

64% in the Middle East; 26% in Saudi Arabia alone

Oil Facts US uses 30% of crude oil extracted; 68% for transportation $ per barrel on 6/6/08 $48.92 per barrel 4/22/09 $91.58 per barrel 4/25/13 1 barrel petroleum = 42 gallons

Just How Much Is There? Resource: –A concentration of material that is economically feasible to extract, now or in the future. Reserve: –Portion of the resource that can be extracted now, economically & legally.

Reserves… Production of reserves expected to peak between 2010 and Peaked in US in Undiscovered supplies may extend it years.

Other Sources of Oil Oil Shale: fine-grained sedimentary rock containing kerogen. –Distilled to form shale oil. –Potentially recoverable from CO, UT, WY. –Generally very low grade, takes much energy. Tar sand: mixture of clay, sand, water & bitumen (thick, high sulfur oil). –Most lie below earth’s surface; those close can be mined. –Largest deposits in Canada, UT, Venezuela, Colombia, Russia.

Hubbert’s Prediction for Peak Oil Production