All human activity has an environmental impact. The magnitude and consequences of each impact varies, and environmental laws have been created to regulate and minimize these impacts.

Electrical power generation has several major potential and actual environmental hazards, including air emissions and water and soil contamination (table 1). Fossil fuel plants have been a particular concern because of their emissions into the air of nitrogen oxides (see “Ozone” below), sulphur oxides and the “acid rain” question, carbon dioxide (see “Global climate change” below) and particulates, which have recently been implicated as contributing to respiratory problems.

Table 1. Major potential environmental hazards of power generation

* Should include such “local” effects as increases in temperature of the body of water receiving plant discharges and reductions in fish population due to the mechanical effects of feedwater intake systems.

The concerns with nuclear plants have been with the long-term storage of nuclear waste, and the possibility of catastrophic accidents involving the release of radioactive contaminants into the air. The 1986 accident at Chernobyl, in Ukraine, is a classic example of what can happen when inadequate precautions are taken with nuclear plants.

With hydroelectric power plants, the main concerns have been leaching of metals and disturbance of both water and land wildlife habitats. This is discussed in the article “Hydroelectric power generation” in this chapter.

Electromagnetic Fields

Research efforts regarding electromagnetic fields (EMF) around the world have been growing since the study by Wertheimer and Leeper was published in 1979. That study suggested an association between childhood cancer and utility wires situated near homes. Studies since that publication have been inconclusive and have not confirmed causality. In fact, these subsequent studies have pointed to areas where greater understanding and better data are needed to be able to start to draw reasonable conclusions out of these epidemiological studies. Some of the difficulties of performing a good epidemiological study are related to the problems of assessment (i.e., the measurement of exposure, source characterization and levels of magnetic fields in the residences). Even though the most recent study released by the National Research Council of the National Academy of Sciences (1996) determined that there was not enough evidence to consider electric and magnetic fields threatening to human health, the issue will probably remain in the public’s eye until the widespread anxiety is alleviated by future studies and research which show no effect.

Global Climate Change

Over the past few years public awareness has increased concerning the impact that humans are having on the global climate. Approximately half of all greenhouse emissions from human activity are thought to be carbon dioxide (CO₂). Much research on this issue on a national and international level has been and continues to be done. Because utility operations make significant contributions to the release of CO₂ to the atmosphere, any rulemaking for the control of CO₂ releases has the potential to impact the power generation industry in serious ways. The UN Framework Convention on Climate Change, the US Climate Change Action Plan and the Energy Policy Act of 1992 have created strong driving forces for the power industry to comprehend just how it might have to respond to future legislation.

Presently, some examples of the areas of study taking place are: the modelling of emissions, determining the effects of climate change, determining the costs associated with any climate change management plans, how humans might benefit by reducing greenhouse gas emissions, and predicting climate change.

A major reason for concern about climate change is the possible negative impacts on ecological systems. It is believed that systems that are not managed are the most sensitive and have the highest probability for significant impact on a global scale.

Hazardous Air Pollutants

The US Environmental Protection Administration (EPA) has sent to the US Congress an Interim Report on Utility Hazardous Air Pollutants, which had been required by the 1990 Clean Air Act Amendments. The EPA was to analyse the risks from fossil fuel-fired steam electric generating facilities. EPA concluded that these releases do not constitute a public health hazard. The report delayed conclusions about mercury pending additional studies. A comprehensive Electric Power Research Institute (EPRI) study of fossil-fired power plants indicates that greater than 99.5% of the fossil power plants do not yield cancer risks above the 1 in 1 million threshold (Lamarre 1995). This compares with the risk due to all emission sources, which has been reported to have been as high as 2,700 cases per year.

Ozone

Reduction of ozone levels in air is a major concern in many countries. Nitrogen oxides (NO_x) and volatile organic compounds (VOCs) produce ozone. Because fossil fuel power plants contribute a large component of the world’s total NO_x emissions, they can expect tighter control measures as countries tighten environmental standards. This will continue until the inputs for the photochemical grid models that are used for modelling tropospheric ozone transport are more accurately defined.

Site Remediations

Utilities are having to come to terms with the potential costs of manufactured gas plant (MGP) site remediation. The sites were originally created through the production of gas from coal, coke or oil, which resulted in onsite disposal of coal tar and other by-products in large lagoons or ponds, or in the use of offsite for land disposal. Disposal sites of this nature have the potential to contaminate groundwater and soil. Determining the extent of groundwater and soil contamination at these sites and the means to ameliorate it in a cost-effective manner will keep this issue unresolved for some time.

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