Clean Energy

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Clean Energy


In recent years, increasing attention has been paid to the development and use of renewable energy sources, also known as clean energy. Many of these energy sources focus on generating electricity while reducing or eliminating the use of fossil fuels and greenhouse gases, and pollutants that they produce. Another related area of interest is the development of alternative fuels for cars and trucks. Traditional sources of energy, such as coal and natural gas power plants, are also becoming less polluting with the use of new technology.

Several important influences have driven the current enthusiasm for clean energy. A growing scientific consensus that climate change threatens human and animal life has raised interest in reducing greenhouse gases from energy consumption. Increasing oil prices, and the realization that supplies will eventually be depleted, drive interest in alternative fuels for transportation, energy generation, and household use. Furthermore, there is growing concern that dependence on oil from foreign sources decreases national security while supporting oppressive foreign regimes.

Historical Background and Scientific Foundations

Humanity has a long history of employing clean energy sources to do useful work. For much of our existence, clean, renewable sources of energy were the only available options. The burning of wood for heat, light, and food preparation is one of the oldest energy sources. In parts of the world where wood is not abundant, different fuels including dung, peat, grasses, and other plant materials have been used. Wood is still a significant source of renewable energy, surpassing the use of all other clean technologies. It should be noted that while the burning of wood does not release new carbon dioxide into the atmosphere, it can contribute to global warming if trees are not replanted. Wood smoke can also be a major source of air pollution.

Other sources of clean energy have long been used in industry and agriculture. Wind power was one of the earliest clean energy sources to be exploited, with sailing ships acting as the main agents of commerce from ancient times to the 1800s. In the Middle Ages, windmills began to appear in Europe, possibly influenced by Persian technology. The windmill turned the energy of wind into the ability to do mechanical work, and was used for both grinding grain and pumping water. Later, the Dutch even used windmills to power industrial machines.

Another very old source of clean energy is the watermill, which uses the power of moving water. The use of watermills extends back to at least the Roman era. The Romans used watermills to grind grain more efficiently than the traditional human- or animal-powered grindstones. Some of their later technology was very advanced, using a cascade of water to power several mills in a series or harnessing the power of tides. The refinement of watermills continued through the Middle Ages and Renaissance, and even powered the early Industrial Revolution. Sawmills, textile mills, paper mills, metal-rolling mills, and even early blast furnaces were powered by watermills.

Issues and Impacts

Perhaps the most powerful issue influencing energy is the threat of global warming due to greenhouse gases. Although some opposition to the idea persists, the scientific consensus agrees that the average global temperature is increasing and that this increase is caused by human activity, specifically because of the release of greenhouse gases into the atmosphere. Carbon dioxide (CO2) is one of the most abundant greenhouse gases because it is released by the combustion of most fuels. Fossil fuels increase the amount of carbon dioxide in the atmosphere because when burned they release carbon that was trapped in the earth millions of years ago.

In the United States, 39% of the total energy consumed is used to generate electricity, and 50% of all electricity is generated by coal. Coal is a fossil fuel that, while available in abundance from within the United States, can cause serious environmental and health problems when used for power generation. Emissions from coal power plants such as carbon dioxide, sulfur dioxide, nitrogen oxide, particulate matter, arsenic, mercury, and carbon monoxide cause or exacerbate lung and heart disease, some cancers, acid rain, and smog.

New “clean coal” technologies aim to reduce emissions of carbon dioxide, particles, and dangerous chemicals from coal-fired power plants, as well as increasing efficiency. Experimental technologies that trap carbon dioxide in the earth could also be used to reduce the environmental impact of coal and other fossil fuels. Some environmental groups are skeptical of “clean coal” technologies; however it should be noted that with coal providing a large portion of the world’s energy, especially in fast-growing China and India, the use of coal will continue for the foreseeable future.

The technologies known as green power have generated considerable excitement in the clean energy movement. These include power generated by solar, wind, tidal, hydroelectric (in some applications), geothermal, biomass, and biofuel methods. Solar power has a broad range of available uses, from passive solar heating in homes to large utility plants that use reflective mirrors to generate steam for electricity generation. The use of photovoltaic solar cells to generate electricity has been gaining popularity as equipment prices decrease.

Like solar power, wind generation can also be used in a variety of settings. Small wind turbines are available for home use, but can be less effective when wind speeds are low. Large wind farms are increasingly being placed in windy locations, both on land and offshore, to produce commercial amounts of power. Large hydroelectric plants, made possible by massive dams, are a much-used source of electricity. However, the sizable environmental impact, as well as the fact that many of the rivers that can be easily dammed have already been utilized, will restrict future growth of hydroelectric power.

Many other technologies are currently restricted to smaller applications, though most have potential for growth. Tidal turbines are taking the place of ancient watermills, and biomass is being used to co-generate heat and electricity in many large buildings, particularly factories that create wood or other plant wastes. Geothermal power and the use of heat pumps is a viable, but little-used source of clean energy.


BIOMASS: The sum total of living and once-living matter contained within a given geographic area; or, organic matter that can be converted to fuel and is regarded as a potential energy source.

CO-GENERATION: The simultaneous generation of both heat and electricity at one facility.

TURBINE: An engine that moves in a circular motion when force, such as moving water, is applied to its series of baffles (thin plates or screens) radiating from a central shaft.

Economics is one major factor in slowing the implementation of many clean energy technologies: Fossil fuels, though increasing in price, are still often less expensive than clean alternatives. The costs associated with the transition to a new energy source can be a barrier to their adoption. Some companies are offering renewable energy credits for purchase, which use the cost to finance clean energy ventures. Certain markets are also offering green pricing to customers, who pay a lesser rate when energy is in lower demand. Conservation and efficiency offer the greatest potential for decreasing the environmental impact of any type of energy use. However, they are also some of the most difficult to implement, because they often require the cooperation of millions of individual consumers.

Despite these difficulties, the future of clean energy is promising. These new technologies will protect the environment, create new jobs, and bring energy to areas that are currently undeveloped. By increased implementation of clean energy, the hidden impacts of fossil fuels on health and the environment can be decreased while bringing benefits to much of humanity.

Primary Source Connection

The following news article addresses the conflict between protecting the habitat of endangered orca whales and running CO2 (shown in the article as CO2) emissions-reducing hydropower operations in the Pacific Northwest’s Columbia River basin, where whales feed on endangered wild salmon. Because the salmon numbers have depleted since the installation of dams in the area, the orcas cannot feed on their intended diet, thus also depleting in number. The article mentions several options for solving the problem, though still ends with the question of which environmental issue will be solved, if not both are complied with.


It’s an environmental conundrum: As states try to meet their clean-energy goals, must endangered species pay a price? That’s the question facing Washington and Oregon—and the endangered orcas living in Puget Sound.

Dams in the Columbia River Basin have been a major cause of plummeting salmon populations in the Pacific Northwest for decades. It’s a problem that costly government programs so far have failed to solve, despite continual federal court orders.

Scientists and policymakers now realize the situation could become worse as climate change looms and other iconic ocean species are affected as well—a classic tale about the interconnectedness of environmental challenges and their solutions.

Six prominent scientists recently warned that the survival of endangered orcas in Puget Sound, which rely on salmon for sustenance, could rest on the removal of four major dams along the basin.

But thanks largely to hydropower operations on the Columbia and Snake Rivers, the region is relatively green in terms of climate-changing gas emissions compared with other parts of the US. How to reduce the effects, if not the risk, of global warming while also protecting endangered species is the problem.

Both wild salmon and orcas (also known as killer whales) are listed under the federal Endangered Species Act,

which means government agencies must find ways to recover dwindling numbers.

“Their futures are intricately linked,” says Rich Osborne, research associate with the Whale Museum in Friday Harbor, Wash., and one of the six orca scientists who recently wrote to members of Congress from the Northwest and the regional administrator for the National Marine Fisheries Service.

Puget Sound orcas, grouped into three family units, now number in the 80s—a drop of at least one-third from historic levels. Columbia Basin salmon runs today are no more than 10 percent of pre-dam times, when millions traveled between the Pacific Ocean and upstream spawning grounds.

“The science is clear that removing four federal dams on the lower Snake River is needed to avert extinction of the Snake’s four unique salmon populations,” the scientists wrote.

Removing the dams would restore 140 miles of the Snake River to a more natural, free-flowing state, they wrote, substantially increasing both spawning habitat for salmon and a critical food source for killer whales, which can consume some 500 pounds of salmon a day.

Dam removal also would help avert extinction of the salmon species that are most likely to survive global warming. Salmon rely on cool water, and their spawning streams in the upper reaches of the Columbia/Snake river system will warm the least. “Climate change effects

are a key factor in the survival of species such as salmon and killer whales,” the scientists wrote.

Oregon Gov. Ted Kulongoski (D) and Washington Gov. Christine Gregoire (D) both want to reduce greenhouse-gas emissions in their states to 1990 levels or below. Even for these relatively green states, that’s a tall order.

The Pacific Northwest emitted about 44 million tons of CO2 in 1990, a figure that rose to 67 million tons in 2005, according to the Northwest Power and Conservation Council, which was created by Congress in 1980 to deal with energy and environmental issues related to the region’s dams. Even with more renewable energy sources—such as wind power and biomass, both of which are growing in the region—greenhouse-gas emissions are likely to rise due to an expanding population and economy, the NPCC reported earlier this month.

In planning energy needs for the next several decades, the council warns against breaching the Snake River dams. “Given the difficulty of reducing CO2 emissions, discarding existing CO2-free power sources has to be considered counterproductive,” the council wrote.

Meanwhile, the legal battle continues over endangered salmon (and their predators, endangered orcas).

Breaching major hydropower dams, which is opposed by developers, industry groups, irrigators, and most elected officials, is off the table as far as the Bush administration is concerned. But federal courts rejected proposed plans for salmon recovery as too little, too late.

Another plan was offered last month. It involves what the National Marine Fisheries Service calls “an aggressive and comprehensive series of hydropower system improvements, hatchery reforms, and habitat enhancements.” Once again, federal courts will determine whether that’s sufficient.

Environmentalists are watching closely. Says Ken Balcomb, executive director of the Center for Whale Research, who signed the recent letter: “History will not be very forgiving of the resource managers who failed in their responsibilities to these icons of the Pacific Northwest.”

Brad Knickerbocker


See Also Coal Resource Use; Industrial Pollution; Clean Air Mercury Rule of 2005


Web Sites

Michigan Energy Center Network. “Fossil Fuels: A Short Blip in History.” Michigan Renewable Energy Success Stories.” 2003–2004. (accessed February 29, 2008).

Michigan Energy Center Network. “A Possible Roman Tide Mill.” Kent Archaeological Society.” 2003–2004. (accessed February 29, 2008).

Union of Concerned Scientists. “Coal Power: Air Pollution.” August 18, 2005. (accessed March 1, 2008).

Uranium Information Centre Limited. Melbourne, Australia. “Clean Coal” Technologies.” February 2008. (accessed March 1, 2008).

U.S. Environmental Protection Agency. “Clean Energy, Basic Information.” December 28, 2007. (accessed March 1, 2008).

Windmill World. “History of Windmills.” February 24, 2004. (accessed February 29, 2008).

Kenneth Travis LaPensee