Renewable Energy

by

Dustin Mulvaney

• LAST REVIEWED: 24 July 2018
• LAST MODIFIED: 28 June 2016
• DOI: 10.1093/obo/9780199874002-0138

Introduction

A renewable energy source is one that is constantly replenishing itself, including power harnessed from the sun, wind, moving water, and geothermal sources. Energy use by human civilization is best understood in contrast to nonrenewable energy sources, including fossil and fissile fuels, which can be exhausted when resources are depleted at rates faster than they are reproduced. Renewable energy is human civilization’s oldest energy resource. For most of human history, civilization was powered by renewable energy, until the discovery of fossil fuels in the 18th century. Ecological economists differentiate renewable and nonrenewable energies using the concepts of stocks and flows. This permits a useful analogy for describing the sustainability of renewable energy. The consumption of stocks of fossil fuels, which can take hundreds of millions of years to accumulate, can eventually deplete energy reserves, much like spending savings in a savings account. The use of flows of renewable energy, which are constantly replenishing, is analogous to spending current income. This suggests that renewable energy sources are sustainable energy sources because they cannot be drawn down. The use of stocks of fossil fuels and uranium has implications for intergenerational equity, because the more of it we consume today means fewer energy sources will be available to future generations. The social and environmental issues of conventional, nonrenewable energy extraction and use are widely documented. In addition to concerns about future energy supplies, the burning of fossil fuels causes greenhouse gas emissions, the emission of criteria air pollutants, wastewater emissions, and water use for extraction, processing, and even cooling. Most research shows that renewables perform much better than conventional energy sources when comparing environmental metrics. Some renewables do pose impacts, such as burning biomass, which has high water use and pollution and poses air quality problems. Most renewables have increased land use requirements compared to nuclear and fossil fuels. The latter points to the critical need for geographers to engage in renewable energy issues, because increased demand for renewables translates to an increased need for land.

General Overviews

Since Lovins 1976, which called for a move away from the hard paths of nuclear energy and fossil fuels toward the soft paths of renewable energy, the exploration of spatiality and renewable energy has been a research topic in geography and energy studies. The historical perspective on the biophysical limitations is an appropriate starting point, since natural resource extraction is grounded upon such limits. One common theme across all of these books is their emphasis of the power density limits of renewables and their consequences for land use. Of the numerous excellent scholars on the topic, Vaclav Smil’s authorship is most prolific. Smil 2000 represents the kind of big-picture thinking about the historical context of energy development and transitions found throughout his analyses. This work is an excellent starting point for those looking to situate civilization’s increasing appetite for energy and the development of new technologies to transform energy. There are a number of other authors who provide a framework for the biophysical understandings of energy. MacKay 2008 and Wolfson 2011 are excellent introductory textbooks that take a deep dive into energy and renewables. These tend to be excellent readings for introductory energy and environmental studies courses, as well as to familiarize researchers looking to engage in renewable energy topics. These texts also cover several energy technologies not widely represented in geographical research. The so-called wind, water, and sunlight (WWS) strategies developed in Delucchi and Jacobson 2011 have become the basis for the “solution project” blueprints that illustrate ways that states, nations, and regions can obtain all of their energy from renewables.

• Delucchi, Mark A., and Mark Z. Jacobson. “Providing All Global Energy with Wind, Water, and Solar Power, Part II: Reliability, System and Transmission Costs, and Policies.” Energy Policy 39.3 (2011): 1170–1190.

  DOI: 10.1016/j.enpol.2010.11.045

  The research team proposes a strategy to power global energy demands with wind, water, and solar (WWS) energy technologies. Part II reviews the key policies, economics, and other critical requirements to drive this approach.

• Jacobson, Mark Z., and Mark A. Delucchi. “Providing All Global Energy with Wind, Water, and Solar Power, Part I: Technologies, Energy Resources, Quantities and Areas of Infrastructure, and Materials.” Energy Policy 39.3 (2011): 1154–1169.

  DOI: 10.1016/j.enpol.2010.11.040

  Part I of a two-part series (see also Delucchi and Jacobson 2011) that demonstrates the feasibility of powering all of global energy demands with wind, water, and solar. These strategies have become common talking points and national and state-by-state WWS strategies have followed since these two papers were initially published.

• Lovins, Amory. “Energy Strategy: The Road Not Taken?” Foreign Affairs (October 1976): 186–218.

  Lovins’s celebrated essay distinguished between hard and soft energy paths in an effort to describe a strategy for a renewable energy–powered civilization and away from the hard technologies of oil, coal, and nuclear power. Energy efficiency and conservation are critical parts of the soft path strategy and remain core elements of Lovins’s work with the Rocky Mountain Institute.

• MacKay, David. Sustainable Energy—Without the Hot Air. Cambridge, UK: UIT, 2008.

  MacKay’s book is widely used to introduce key topic in energy studies. MacKay stresses the importance of understanding the quantitative dimensions of energy, emphasizing the need to know numbers, not adjectives. Among the key spatial concepts explored in the book is power density, which describes how much power flux can be generated per unit of land.

• Smil, Vaclav. “Energy in the Twentieth Century: Resources, Conversions, Costs, Uses, and Consequences.” Annual Review of Energy and the Environment 25.1 (2000): 21–51.

  DOI: 10.1146/annurev.energy.25.1.21

  Smil describes the historical context for the emergence of fossil fuels and electricity and the subsequent growth in energy use by human civilization. He provides an overview of some of the consequences of the major prime movers described, including environmental costs and benefits to standards of living.

• Wolfson, Richard. Energy, Environment, Climate. 2d ed. New York: W. W. Norton, 2011.

  This book provides a background on the biophysical concepts that underlie energy issues. The book revisits important concepts from chemistry, physics, and biology and connects energy problems to their contemporary social and environmental contexts. It is an excellent teaching text for courses such as energy and the environment.