We derive our energy from a multitude of resources that have varying environmental challenges related to air and water pollution, land use, carbon dioxide emissions, resource extraction and supply, as well as related safety and health issues. Each resource needs to be evaluated within the sustainability paradigm. Coal (45 percent) and gas (23 percent) are the two primary fossil fuels for electricity production in the United States. Coal combustion produces nearly twice the carbon emissions of gas combustion. Increasing public opinion and regulatory pressure to lower carbon emissions are shifting electricity generation toward gas and away from coal. Oil for transportation and electricity generation are the two biggest users of primary energy and producers of carbon emissions in the United States. Transportation is almost completely dependent on oil and internal combustion engines for its energy. The concentration of oil in a few regions of the world creates a transportation energy security issue. Nuclear electricity offers the sustainable benefit of low carbon electricity at the cost of storing spent fuel out of the environment for up to hundreds of thousands of years. Reprocessing spent fuel offers the advantages of higher energy efficiency and reduced spent fuel storage requirements with the disadvantage of higher risk of weapons proliferation through diversion of the reprocessed fuel stream.
Strong interest in renewable energy arose in the 1970s as a response to the shortage and high price of imported oil, which disrupted the orderly operation of the economies and societies of many developed countries. Today there are new motivations, including the realization that growing greenhouse gas emission accelerates global warming and threatens climate change, the growing dependence of many countries on foreign oil, and the economic drain of foreign oil payments that slow economic growth and job creation. There are three ultimate sources of all renewable and fossil energies: sunlight, the heat in the earth’s core and crust, and the gravitational pull of the moon and sun on the oceans. Renewable energies are relatively recently developed and typically operate at lower efficiencies than mature fossil technologies. Like early fossil technologies, however, renewables can be expected to improve their efficiency and lower their cost over time, promoting their economic competitiveness and widespread deployment. The future deployment of renewable energies depends on many factors, including the availability of suitable land, the technological cost of conversion to electricity or other uses, the costs of competing energy technologies, and the future need for energy.
1. Which one of the following is not a renewable source of energy?
2. Coal, oil, and natural gas are created _______ and contain the remains of__________.
A. over millions of years; algae and plants
B. over millions of years; dinosaurs and other animals
C. over hundreds of years; algae and plants
D. over hundreds of years; dinosaurs and other animals
E. instantaneously; comet fragments
3. Which one of the following is a consortium of oil-producing countries that hold a significant portion of the world’s oil reserves (and thus influence global oil prices)?
4. About 44% of the electricity in the US is produced from _________. It produces about twice as much CO2 as an equivalent amount of _______.
A. Burning natural gas; coal
B. Hydropower; solar
C. Natural gas; Geothermal
D. Hydropower; geothermal
E. Burning coal; natural gas
5. Which one of the following is not true regarding nuclear power?
A. Energy is captured from the radioactive decay of elements
B. Nuclear power is considered an alternative fuel
C. Radioactive wastes must be stored 2-5 years before disposal
D. No CO2 is directly produced in nuclear power plants
E. Nuclear power is used to produce electricity
6. Which one of the following directly produces CO2 but is considered carbon neutral?
7. The original source of energy that powers both wind energy and hydropower is…
B. Rotation of the Earth
C. The sun
E. Radioactive decay within the Earth’s mantle
8. Burning sawdust that is leftover from lumber production and using it to generate electricity would be an example of which one of the following?
A. Municipal solid waste
9. In the process of fracking, how is gas and oil extracted?
A. Layers of earth are stripped away from the surface, exposing the fossil fuels
B. Mining tunnels are created and the fossil fuels are extracted by teams working below ground
C. Ocean sediments are mined and the fossil fuels are chemically extracted
D. High-pressure fluids are injected underground to force out the fossil fuels
E. Offshore drilling pads tap into pre-existing cracks in the Earth’s crust
10. What fundamental similarity is shared between the following energy sources: biogas and municipal solid waste?
A. Both burn waste to generate CO2, which itself is burned to create electricity
B. Both chemically transform waste into oil
C. Both trap the heat generated from decaying waste and use it to generate energy
D. Both rely on the generation and combustion of methane
E. Both produce no CO2
See Appendix for answers
EEA. (2013). Combined heat and power. Retrieved from http://www.eea.europa.eu/data-and-maps/indic ators/combined-heat-and-power-chp-1. Available under Creative Commons Attribution License 3.0 (CC BY 3.0). Modified from original.
Theis, T. & Tomkin, J. (Eds.). (2015). Sustainability: A comprehensive foundation. Retrieved from http://firstname.lastname@example.org. Available under Creative Commons Attribution 4.0 International License. (CC BY 4.0). Modified from original.
Page attribution: Essentials of Environmental Science by Kamala Doršner is licensed under CC BY 4.0. Modified from the original by Matthew R. Fisher. “Review Questions” is licensed under CC BY 4.0 by Matthew R. Fisher.