Energy and the Natural Environment
by David A. Dobson, Ph.D.
This article is the second in a series, to appear in issues of the Warbler, dealing with energy sources, uses and technologies from various perspectives.
Understanding Energy Policy Issues and Primary Energy Sources
Energy use is so closely linked to the economy, and to our lifestyles, that energy policy decisions are heavily value laden and energy debates are often highly politicized. Discussions of energy policy are inherently complex and filled with specialized terminology. Add political obfuscation, and most readers become puzzled and misinformed. My goal in this article is to clarify some of the critical issues, without advocating particular policies or discussing possible means to bring these policies into effect.
The US economy and many others around the world depend critically upon oil from the Middle East. Nearly everyone agrees that this is not a good situation, but that it will be a real challenge to resolve it. Energy demand and consequent pressures on the environment tend to increase as economies expand to meet population growth and rising expectations around the world. There are no simple solutions and no single answers to this challenge.
A bewildering array of ideas has been proposed to fill our growing need for energy, including:
Side effects and associated concerns include pollution and destruction of local environments, global warming, infrastructure costs and national security issues.
To see how these ideas might fit together, we must clearly understand the concept of a primary energy source: A primary source of energy is one that already exists in nature and can be used directly, or converted or re-directed into a form of energy that satisfies our needs. The primary sources of energy available to us are:
By contrast, secondary energy sources, such as electric power or refined fuels, do not exist in nature, but can be produced from the primary energy sources listed above. Secondary sources are important because they are frequently easier to use than the primary sources from which they are derived. The scientific principle of conservation of energy is very well established. It guarantees that we will never be able to devise a means to produce more secondary energy than the amount of primary energy that was required to make it. Therefore, our ability to use energy will always be strictly limited by the availability of primary energy sources.
The good news is that solar energy is abundant, except in the polar regions, it's freely available to everyone, and it will continue for another 5 billion years, according to astrophysicists. If we recognize that we depend on solar energy to keep our environment warm enough to support life as we know it, and that we depend ultimately on solar photosynthesis for all our food, it's clear that we actually depend far more on solar energy right now than on all the other primary energy sources combined, and we always will.
Because solar radiation is spread out over the entire illuminated side of the globe, it is not as convenient to use for commercial purposes as the fossil or nuclear fuels, which can be transported to an industrial site for conversion to electricity. Wind, which should be regarded as a derivative of solar, tends to be more selectively concentrated at windy sites, which are more easily exploited as locations for wind machines. Most solar energy developments have low environmental impact, because they do not release poisonous materials into the environment, despoil the land or significantly alter natural energy flows on the planet.
For the past century and more we have relied heavily on fossil fuels, and world demand for them continues to grow as an accelerating rate. The amount of recoverable gas and oil on the planet is finite, and the projected lifetime of these consumable resources is estimated to be a few decades at current rates of consumption. Prices will rise, as extraction becomes more and more costly. Coal is abundant by comparison, with resources projected to last hundreds of years, even with expanded consumption levels. But continued use of this coal, even at current consumption levels poses a number of serious threats to the environment. Water pollution with sulfuric acid and air pollution with sulfur oxides and toxic trace elements in the coal, such as mercury and radium have been classic threats with coal use. Removal and control of these pollutants is a cost issue and an enforcement issue. The threat of global warming, as a consequence of Carbon Dioxide release, is a much greater problem. Coal is mostly Carbon, and the burning of one ton of coal will release about three tons of Carbon Dioxide into the environment. There is no reliable way to sequester it, though schemes to pump it underground have been suggested. The best way to minimize the global warming crisis is to not burn the coal. Leave it in the ground!
The most economical means to meet future energy demand is to make every effort to improve energy efficiency, to get more productive value out of each unit of primary energy that we use. Also we should make every reasonable effort to develop renewable resources (solar and wind). If we minimize, or at least don't expand the use of coal, it's not likely that world energy demands can be met without a greater reliance on nuclear energy, as a supplement to renewable sources. I plan to expand on nuclear energy resources, discussing their pros and cons, and also to discuss secondary energy sources in subsequent issues of the Warbler.