Summary

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.

Review Questions

1. Describe three major environmental challenges for fossil fuels in general or one in particular.
2. What are the compelling reasons to continue using coal in spite of its challenges?
3. Rate the following electricity sources for their contribution to climate change from most to least: biomass, coal, solar, wind, nuclear, natural gas, oil, geothermal, hydroelectric, MSW
4. Describe the environmental and social concerns with regard to biofuels.
5. Nuclear fuel can be used once and committed to storage or reprocessed after its initial use to recover unused nuclear fuel for re-use. What are the arguments for and against reprocessing?
6. Public acceptance is a key factor in the growth of renewable energy options. What is the public acceptance of various energy options, and how might these change over the next few decades?
7. There are many reasons to reduce consumption of oil, including an ultimately finite supply, the high cost and lost economic stimulus of payments to foreign producers, the threat of interruption of supply due to weather, natural disaster, terrorism or geopolitical decisions, and the threat of climate change due to greenhouse gas emissions. Which of these reasons are the most important? Will their relative importance change with time?

Attributions

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://cnx.org/contents/1741effd-9cda-4b2b-a91e003e6f587263@43.5. 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.