ch 13: nonrenewable energy sources

net energy

• amount of high-quality energy available from a given quantity of an energy resource, minus the high-quality energy needed to make the energy available

• net energy = energy output - energy input

energy efficiency

• using less energy to provide the same amount of useful wor

crude oil (petroleum)

• black, gooey liquid containing a mixture of combustible hydrocarbons along with small amounts of sulfur, oxygen, and nitrogen impurities

• aka conventional light crude oil

• formed from the decayed remains of ancient microorganisms that were crushed beneath layers of rock and subjected to high temperatures and pressures for millions of years

  • typically trapped under nonporous rock in the earth’s crust (land and seafloor)

*cannot be used as is

peak production

• point in time when the pressure in an oil well drops and its rate of conventional crude oil production starts declining

refining

• complex process in which crude oil is heated and vaporized in giant columns and separated, by use of varying boiling points, into various products such as gasoline, heating oil, and asphalt

petrochemicals

• used as raw materials to make industrial organic chemicals, cleaning fluids, pesticides, plastics, synthetic fibers, paints, medicines, cosmetics, and many other products

proven oil reserves

• deposits from which oil can be extracted profitably at current prices using current technology

advantages of oil

1. ample supply for several decades

2. net energy is medium but decreasing

3. low land disruption

4. efficient distribution system

disadvantages of oil

1. water pollution from oil spills and leaks

2. env costs not included in market price

3. releases CO2 and other air pollutants when burned

4. vulnerable to international supply interruptions

heavy oil

• mixture of clay, sand, water, and an organic material called bitumen—a thick, sticky, tar-like heavy oil with a high sulfur content

advantages of heavy oil

1. large potential supplies

2. easily transported within and between countries

3. efficient distribution system in place

disadvantages of heavy oil

1. low net energy

2. expensive

3. releases CO2 and other air pollutants

4. severe land disruption

5. water pollution and high water use

advantages of natural gas

1. ample supplies

2. versatile fuel

3. medium net energy

4. emits less CO2 and other air pollutants than other fossil fuels when burned

disadvantages of natural gas

1. low net energy for LNG

2. production and delivery may emit more CO2 and CH4 per unit of energy produced than coal

3. fracking uses and pollutes large volumes of water

4. potential groundwater pollution from fracking

coal formation

1. peat (partially decayed plant matter in swamps)

2. lignite (low heat content, low sulfur content, limited supplies in most areas)

3. bituminous (extensively used as fuel bc of high heat content and large supply, normally largest sulfur content)

4. anthracite (highly desirable fuel bc high heat content, low sulfur content, supplies limited)

advantages of coal

1. ample supplies in many countries

2. medium to high net energy

3. low cost when env costs are not included

disadvantages of coal

1. severe land disturbance and water pollution

2. fine particle and toxic mercury emissions threaten human health

3. emits large amounts of CO2 and other air pollutants when produced or burned

synthetic fuels

• convert solid coal into synthetic natural gas (SNG) by a process called coal gasification

  • removes sulfur and most other impurities from coal

  • can also convert coal into liquid fuels such as methanol and synthetic gasoline through a process called coal liquefaction

advantages of synthetic fuels

1. large potential supply in many countries

2. vehicle fuel

3. lower air pollution than coal

disadvantages of synthetic fuels

1. low to medium net energy

2. requires mining 50% more coal w/ increased land disturbance, water pollution, water use

3. higher CO2 emissions than coal

advantages of nuclear fuel cycle

1. low env impact (w/o accidents)

2. emits 1/6 as much CO2 as coal

3. low risk of accidents in modern plants

disadvantages of nuclear fuel cycle

1. low net energy

2. high overall cost

3. produces long-lived harmful radioactive wastes

4. promotes spread of nuclear weapons