Big Wind and Big Solar:
Avoiding new sets of environmental problems
By JIM DIPESO, REP Policy Director
AN HISTORICAL DOCUMENT: This article first appeared in the C.E.P (Conservative Environmental Policy) Quarterly, summer 2009, Vol 4, #4
One of the raps against renewable energy resources is that they’re too small and dispersed to meet the needs of an energy-hungry country that depends on vast quantities of electricity, heat, and fuel to run the world’s largest, richest economy.
Scaled up to high levels, however, renewables such as wind and solar could supply a significant chunk of the energy needed by homes, businesses, industry, and perhaps, in the not-too-distant-future, electric vehicles, while at the same time lowering harmful emissions.
With big wind or big solar development, however, environmental issues inevitably will arise. The long controversy over the proposed Cape Wind project off the coast of Massachusetts shows that utility-scale, emissions-free power plants can generate environmental controversy as well as electricity.
The environmental and energy security advantages of wind and solar development are too attractive to allow concerns about land, wildlife, and visual impacts to squelch it. Nevertheless, those issues are real. Through a conservative approach to development, including prudent planning and mitigation, the benefits of aggressive wind and solar development could be realized while minimizing impacts on land, wildlife, scenery, and other valuable resources.
The potential for scaling up wind and solar energy production is large. A 2008 report sponsored by the Department of Energy concluded, for example, that meeting 20 percent of America’s electricity needs with wind by 2030 is doable at slightly higher costs compared to a scenario in which 2030 demand is met through growth in conventional resources.
The potential for generating energy from concentrated solar plants (CSP) is immense. In his book, Sustainable Energy – Without the Hot Air, British physicist David MacKay said CSP plants covering 5 million acres in the Southwest – an area about the size of New Jersey – would generate enough power to meet 10 percent of the country’s energy needs.
CSP is capable of generating electricity in large volumes at times when it’s needed most. The plants pour electrons into the grid at the hottest times of day during the summer, when air conditioners are running full bore and power demand peaks.
The U.S. Bureau of Land Management (BLM), which oversees 256 million acres of public lands in the West, has estimated that nearly 12 percent of BLM lands, or 29.95 million acres, has solar energy production potential.
Today, wind and solar account for only 2.6 percent of America’s total electricity generating capacity. That is likely to increase. Between 2004 and 2008, wind capacity grew by an annual average rate of 32 percent.
Interest in CSP development is rocketing upward. On June 29, the Interior Department set aside 670,000 acres of federal lands in the Southwest as “solar energy study areas.” The BLM is reviewing 158 applications to build solar plants that would have generating capacity of nearly 100,000 megawatts, enough to serve one-third of America’s homes.
The growth of wind and solar, in part, is driven by their attractive environmental characteristics.
Unlike coal, they do not emit carbon dioxide, smog-forming air pollutants, or toxic mercury.
Unlike nuclear plants, there are no long-lived radioactive wastes to isolate from the environment for millennia or to recycle in advanced reactors that may not be commercially ready for decades.
Low operating cost is another attractive feature. Unlike natural gas, wind and solar are not subject to fuel price volatility. The fuel is free and always will be, as long as the wind blows and the sun rises in the east.
But neither is free of environmental impacts. For wind, bird and bat mortality caused by collisions with turbines, along with habitat fragmentation and barriers to migration routes, are issues that have drawn scrutiny from wildlife scientists, conservationists, and the wind industry.
Wildlife mortality linked to wind facilities varies by region and species. Lack of adequate research and post-construction monitoring, however, makes it difficult to draw definitive conclusions about wind turbines’ impacts on wildlife, a 2005 Government Accountability Office report said.
For perspective, wind power accounts for a small fraction of bird mortality linked to human factors. Others include collisions with buildings and communications towers, pesticide poisoning, and predation by domestic and feral cats.
CSP faces other types of environmental issues. One is water, always at a premium in the desert Southwest. All of the concentrated solar plants in operation in the U.S. today are “parabolic trough” designs, which use curved reflectors to concentrate the sun’s heat onto tubes filled with an oily fluid. The hot fluid is used to heat water into steam, which is then used to turn power-generating turbines.
CSP plants in operation today consume approximately the same amount of water per kilowatt-hour generated as coal and nuclear plants, totaling about 800 gallons for every megawatt-hour fed to the grid.
There are alternative technologies that could reduce water demand, but they are more expensive than conventional water-cooling methods.
A compromise approach suggested in a Department of Energy report to Congress could be the use of hybrid systems that employ both water and air for cooling. Hybrid systems could reduce water use in a parabolic trough CSP system from 44 to 84 percent. The tradeoffs would be 1-4 percent output reduction and 8 percent increase in costs.
Another issue is land consumption. Unlike wind energy facilities, which can co-exist on open land with farms or ranches, CSP sites – typically 3,000 acres in extent for facilities with 250 to 400 megawatts of capacity, according to BLM – are dedicated exclusively to power generation.
The National Park Service has raised concerns about the potential impacts of large solar arrays on desert parks, including Death Valley, Lake Mead National Recreation Area, and Mojave National Preserve. In a February 5 letter sent to the BLM, the Park Service pointed to potential impacts on wildlife habitat and migration corridors, along with impacts on desert scenery, natural sounds, and dark skies.
Transmission lines to carry power from remote generating sites to urban load centers are the source of similar land impact issues. Federal agencies received numerous comments about transmission impacts on wildlife, scenery, national parks, and wilderness as part of an environmental impact statement on proposed energy corridors on Western public lands.
The EIS, finalized in late 2008, designated 131 corridors on 3.3 million acres of federal lands in 11 Western states. The purpose of the corridors, required by the Energy Policy Act of 2005, is to streamline consideration of project permits.
One way to mitigate transmission impacts, according to a February 2009 report from the Solar Energy Industries Association and American Wind Energy Association, is building lines rated at extra high-voltage. High-capacity transmission lines can move more power over fewer wires than lower capacity lines, helping to mitigate impacts on land and wildlife, the report noted.
One line rated at 765,000 volts can carry as much current as six lines rated at 345,000 volts. While the higher voltage lines cost more than twice as much to build per mile, their per-mile cost for each megawatt of transmission capacity is less than 50 percent that of the lower voltage lines.
In their report, the associations called for building extra high-voltage “green power superhighways” to connect CSP and wind plants to America’s transmission grid. Without those “superhighways,” the report said, wind and solar growth would be stunted.
A solar development alternative that bypasses the costs and controversies of transmission construction is “distributed generation.” Instead of building large-scale concentrated solar plants, the distributed alternative is to build solar photovoltaic systems on rooftops.
Southern California Edison, a utility that serves 14 million people, plans to install 250 megawatts of photovoltaic (PV) panels on 150 commercial building rooftops in its service area. Connecting panels directly to the grid, a 2008 Edison press release said, would eliminate “the costly, time-consuming step of building new transmission lines.”
A distributed generation alternative to concentrated solar plants, however, would be more expensive for meeting California’s 33 percent renewable portfolio standard by 2020, a June 2009 report from the California Public Utilities Commission concluded.
Building only natural gas-fired combustion turbines to meet the state’s demand growth would result in average California electricity prices of 15.4 cents per kilowatt-hour ($2008) in 2020, which is 16.7 percent higher than current prices. Meeting the 33 percent renewables requirement would require a near tripling of renewably generated electricity and seven new transmission lines, bringing average prices to 16.9 cents. An expanded share of distributed generation in a plan to hit the 33 percent mark would result in an average price of 18.1 cents.
“Even if solar PV technology costs drop dramatically, the deployment costs associated with thousands of megawatts of distributed PV could still be a challenge,” the California PUC report noted.
THE CONSERVATIVE APPROACH: GET THE FACTS, PLAN AHEAD
In an attempt to steer concentrated solar to areas with both high production potential and manageable environmental concerns, the Interior Department designated 24 “solar energy study areas” in six Western states, which have a solar energy capacity of up to 135,000 megawatts. One criterion for including lands in the study areas was proximity to transmission lines.
The study areas focus on BLM locations that receive intense solar exposure but are not conservation lands. Excluded from the study areas are units of the National Landscape Conservation System, areas designated as critical habitat for threatened and endangered species, wildlife management areas, and lands with prized scenic qualities.
For wind, biologists recommend independent studies both before and after construction to understand wildlife habitat characteristics and bird behavior at wind facility sites. At the Foote Creek Rim wind project in Wyoming, for example, pre-construction studies showed that raptors tended to use habitat within 50 meters of the rim edge. The solution, consequently, was to build turbines away from the edge.
In addition, biologists have called for standards to identify problem sites where wind energy development should be avoided in order to protect bird and bat populations.
Developing big wind and big solar is critical for building energy security, creating jobs in new manufacturing industries, and reducing greenhouse gas emissions and other pollutants. A careful, conservative approach to planning development would allow their clean energy to be tapped without creating new sets of environmental problems.