7: The Energy System
- Page ID
- 205741
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This chapter explores how humans obtain and use energy to power modern society. Since the Industrial Revolution, fossil fuels such as coal, oil, and natural gas have been the primary energy sources for transportation, electricity generation, industry, and heating. Although these fuels have supported economic growth and technological development, they are finite resources and can cause significant air, water, and land pollution. Their extraction and combustion also release greenhouse gases, primarily carbon dioxide, which are the main drivers of modern global climate change.
When evaluating energy sources, scientists often consider their life cycle impacts. A life cycle assessment examines the environmental effects associated with all stages of an energy technology, including the extraction of raw materials, manufacturing, construction, operation, maintenance, and disposal. For example, although solar panels and wind turbines produce no greenhouse gases while generating electricity, emissions are associated with their manufacture, transportation, installation, and eventual recycling or disposal. Considering life cycle impacts provides a more complete picture of the environmental costs and benefits of different energy sources.
Life Cycle Assessment (LCA): A method used to evaluate the environmental impacts of a product or technology throughout its entire life, from raw material extraction and manufacturing to operation, maintenance, and disposal.
Nuclear fission provides large amounts of electricity with relatively low greenhouse gas emissions over its life cycle. However, concerns remain about radioactive waste, reactor accidents, and the high costs associated with building and decommissioning nuclear power plants. Scientists are also investigating nuclear fusion, the process that powers the Sun. If successfully developed as a commercial energy source, fusion could provide abundant energy with less long-lived radioactive waste than fission, although it remains in the experimental stage.
Renewable energy sources, including solar, wind, hydropower, geothermal, and biomass, are naturally replenished and generally have lower life cycle greenhouse gas emissions and environmental impacts than fossil fuels. Over the past decade, renewable energy technologies have become increasingly cost-competitive, leading to rapid growth in their adoption worldwide. As societies work to reduce greenhouse gas emissions and address climate change, renewable energy is expected to play an increasingly important role in creating a more sustainable energy future.
This chapter examines the advantages, limitations, and environmental impacts of both renewable and nonrenewable energy resources, as well as the challenges and opportunities involved in transitioning to a more sustainable energy system.
- 7.1: Fossil Fuels
- This section covers the historical and present significance of coal and fossil fuels, exploring their origins, extraction methods, and environmental impacts. It notes ancient uses of coal by civilizations like the Aztecs and Romans and discusses fossil fuel formation from ancient ecosystems.
- 7.2: Nuclear Energy
- This page details the 1986 Chernobyl nuclear disaster and its long-term consequences, including a 20,000-year prohibition zone. It weighs the advantages of nuclear energy, like zero greenhouse gas emissions and ample fuel supply, against its drawbacks, such as hazardous waste and accident risks. Concepts like radioactive isotopes and the nuclear fuel cycle are explained, alongside the role of nuclear energy in global consumption and the exploration of fusion potential.
- 7.3: Renewable Energy and Conservation
- This page discusses renewable energy practices, showcasing Portland's use of hydroelectric turbines for sustainable energy without harming waterways. It reviews various sources like wind, solar, geothermal, hydropower, and biofuels, addressing their environmental impact, costs, and efficiencies. The page stresses the need to raise global renewable energy consumption from 11% and highlights the importance of energy conservation efforts.
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