Lecture 6 - Fossil fuels and our changing planet

fossil fuel

hydrocarbon-containing material of biological origin, sourced in the solid earth that can be a source of energy, may include things like coal, petroleum, natural gas, oil sand and heavy oils, they may be burned to produce energy but the reaction released CO2 into the atmosphere, 80% of primary energy production by humans is through fossil fuels, petroleum may be refined into other products like plastics, textiles, paints and fertilizers

exothermic reaction

light the hydrocarbon so it produces H2O, CO2 and energy

divestment

decided link to carbon and our reliance on fossil fuels, dont want to invest in petroleum extraction (it comes from dead dinosaurs, most of what we have is biomass from earth’s past)

hydrocarbons

dead organic matter from plants and animals, energy originally from the sun stored in organic carbon, under the right pressure and temperature will form some type of hydrocarbon, deposited and trapped in the earth’s crust, the mesozoic era is when most of the oil we have was formed

reserve

quantity of resource which is considered to be economically viable to be recovered and used

oil

33% of current energy use, consumption projected to increase

coal

30% of energy use, abundant, expanding reserves but slowly, has impurities in it like sulfur, mercury, arsenic, etc, depends on formation

gas

makes up 24% of energy use, reserves are equivalent to oil reserves

production types

pumping, steam injection and strip mining

petroleum or crude oil

a liquid that can be pumped out of the ground

fracking

method used to extract natural gas and oil from deep underground, usually in a shale (type of rock) that holds the hydrocarbons more closely, it involves injecting large amounts of water, sand and chemicals into a wellbore, the injected fluid helps prop open fractures while sand acts as a proppant to keep fractures from closing when pressure is release, allows trapped gas or oil to flow more freely and be extracted

what is the primary environmental concern with fracking?

its potential impact on groundwater, the injection of fracking fluids and proppants into the well can cause migration of fracking fluid directly into groundwater, flowback of contaminated wastewater at the surface, methane leaks into groundwater

how does fracking induce seismicity?

injection of fracking fluids into ground can change stress field around the fractured layers, this can cause slip/motion on the fractures creating a release of acoustic energy as a small earthquake, creates a micro earthquake (M1-M3 range)

what does combustion of petroleum mean for the earth system?

issue in global change is whether humans significantly disturbing from earth’s carbon cycle so basically combustion of fossil fuels moves carbon in the form of CO2 to the atmosphere which is a greenhouse gas so it helps hold heat in the atmosphere causing global warming

annual total CO2 emission by world region

china is increasing in consumption of CO2 the most followed by india

hockey stick global temperature increase

northern hemisphere anomaly in temperature

liquid petroleum

this is a crude oil mix of many different hydrocarbon compounds, you then separate and isolate these products by refining the oil, follow that with distillation/fractionation of compounds by heating

commercial gas

87 octane is approximately 87% octane and 13% heptane, 92 octane is approximately 92% octane and 8% heptane wiht some additives

combustion of pure octane

it should produce energy, carbon dioxide and water, its a somewhat clean reaction but were dumping CO2 to the atmosphere