18 - Fossil fuels

Energy

• the ability to do work
• different kinds: kinetic, potential, heat, etc.

Work

• The way we transfer energy
• A force over a certain distance
• Work (Joules) = force (N) * distance (m)
• Force (N) = mass (kg) × acceleration (m s^-2)

Power

• The amount of work done in a specific amount of time
• Measured in Watts: 1 W = 1 J s^-1
• 1 Wh (Watt-hour) = 60 (seconds per min) x 60 (min per hr) = 3,600 J

Potential Energy

Energy stored in an object subjected to force:
U = mgh

Kinetic Energy

Energy an object possesses because of motion:
E = ½mv²

primary energy

• contained in natural resources
• non-renewable: derived from sources that exist in limited quantities
• renewable: not depleted when used or can be replenished quickly

secondary energy

primary energy converted to electricity ("power") for consumption

Fossil Fuels

• Process of generating electricity from fossil fuel is 30-40% efficient
• Ex: Coal, Natural Gas, Oil
• Chemical --> Thermal --> Mechanical --> Electrical

Coal

• a solid carbon-based fossil fuel formed from ancient tropical swamps that were buried and subjected to millions of years of immense pressure, becoming sedimentary rock
• the type of coal that forms depends on the original plant material, the conditions of burial & the amount of heat and pressure it's subjected to
• four types of coal in order of increasing carbon & energy content: Lignite, Sub-bituminous, Bituminous, Anthracite
• first fossil fuel widely used & still most abundant fossil fuel produced in the US
• mostly used to produce electricity
• China is the world's leading producer & consumer of coal
• extracted from underground mines using boring machines, and from surface mines by using blasting & machinery
• some regions use mountaintop removal, removing entire mountaintops to scoop out underlying coal, then depositing waste in adjacent valleys
• water that drains from coal mines is often acidic & has heavy metals, resulting in destruction of aquatic habitats
• Coal can meet today's energy demand for the next 300 years
• Problems: landscape impacts, acidic water drainage, emissions when burning, including sulfur dioxide, nitrogen oxides, particulates, carbon dioxide, methane, mercury

Hydrocarbons

• materials made of strands of hydrogen & carbon molecules derived from ancient, solar energy-capturing photosynthesis
• examples: oil & natural gas

Oil

• most consumed fuel in world
• refined form of oil is gasoline
• Middle East has 55% of world's proven oil reserves
• oil deposits form in rocks and are extracted by drilling and pumping
• secondary extraction: water is injected to increase pressure, forcing more oil to surface
• tertiary extraction: steam is injected to allow oil to flow more easily from rock into well
• each oil well requires drilling pad and road to access it, and processing facilities nearby
• pipelines transport oil or natural gas: 72,000 miles of crude oil pipelines in US
• global reserves are sufficient to provide 54-year supply at current production levels
• burning oil produces same polluting emissions as coal, accounting for ~45% of CO2 emissions in US

Hydraulic fracturing (fracking)

• Injecting a mixture of water, sand & chemicals to crack open shale & release oil/gas
• Boomed in the 2000s, US has the fastest-growing fracking market
• Can cause water contamination, health impacts, earthquakes

Tar sands

• oil bonded with loose-grained rock deposits
• Extracting oil from tar sands requires a lot of land, water & energy, & produces a lot of waste

natural gas (methane)

• fastest growing fossil fuel energy source, surpassed coal in the US
• found with oil deposits or on its own
• bound in layers of shale or other impermeable rock formations
• natural gas releases 30% less CO2 than oil & 50% less than burning coal per unit of heat produced
• downside is that it requires large network of pipelines
• may leak as much as 12% of methane extracted, which adds to GHG

Rise of Fossil Fuels

• Prior to the industrial revolution, people burned wood and manure for heating and cooking, water mills to grind grains and used carts and animals for transportation
• In the 16th and 17th century a firewood shortage drove up prices, making industrialized economies turn to coal
• Challenge of extracting coal in 1700s led to invention of steam engine (James Watt) to power water pumps and conveyors to bring up coal from deeper depths
• Up-front and maintenance costs associated with new energy technologies may limit initial adoption rates
• Governments provided subsidies and tax breaks to the fossil fuel industry, supporting exploration and technology development, making fossil fuels cheaper and more accessible to consumers
• State governments granted monopolies to utility companies as incentives to make huge investments in power lines
• Between 1978-2004, federal government invested > $25 billion in fossil fuel energy research
• Fracking was also funded by US Department of Energy in 1970s

Reserve

• known resource of a fossil fuel that can be economically accessed with current technologies
• Technological advances make resources more available and expand considerations of proven reserves
• Conventional reserves are easily obtained deposits
• Unconventional reserves are difficult-to-extract deposits

Consumption of Fossil Fuels

• Globally, fossil fuels account for 80% of energy use
• All other non-fossil fuels account for 20% of energy used
• World energy consumption has steadily increased, averaging > 2% each year in past decade
• In US, we consume >300 tons of fossil fuels every second
• US Consumption ranked: petroleum, natural gas, renewable, coal, nuclear

Environmental Impacts

• Fossil fuels must be mined & burned to provide energy
• Coal, oil, & natural gas all have impacts associated with extracting material and processing it to be used for energy
• This results in air, water, & land pollution, as well as release of large amounts of greenhouse gases

Cost of Fossil Fuel Dominance

• Fossil fuels are a finite resource; extraction will be more difficult as resources decline
• These resources are not evenly distributed throughout the world
• Competition for fossil fuels has been source of international conflict & raises national security concerns & costs in many countries
• Social cost of carbon: an estimate, in dollars, of the economic damages that would result from emitting one additional ton of CO2 into the atmosphere
• E.g. agricultural productivity, damages caused by sea level rise, decline in human health or labor productivity

Factors that will Impact the Future of Fossil Fuels

• Shrinking of collective share of energy market of fossil fuels due to advancements in alternative technologies & increased costs
• As environmental & economic costs associated with fossil fuels continue to rise, choices we make regarding energy options may change quickly
• Governmental policies to increase cost of fossil fuels encourage energy conservation & development of alternative energy resources

cap-and-trade program

• government sets overall maximum allowable emissions standard then creates market that enables allowances to be bought, sold, traded, or saved
• creates incentive for companies to reduce pollution & higher operating costs for companies that pollute more
• California's 2013 cap-and-trade system decreased cap each year to meet pollution-reduction goals
• state gains $2 billion per year, deposited in Greenhouse Gas Reduction Fund that invests in alternative energy & other efforts to reduce carbon emissions

If a Joule is the energy a person at rest releases as heat every hundredth of a second, and you all (150 students) are in this room for the duration of a lecture (90 min), how much energy would have been generated and released?

81,000,000 J

150 x 90 x 60 x 100

Coal is an example of energy. (Select all that apply.)
A. nonrenewable
B. renewable
C. primary
D. secondary

A. nonrenewable
C. primary

In terms of GHG pollution, the least damaging fossil fuel is ________.
A. coal
B. oil
C. natural gas

C. natural gas