Wind energy in the United States and globally: Research roundup
When the House of Representatives approved the Senate’s emergency “fiscal cliff” deal on New Year’s Day 2013, one of the winners was the U.S. wind-power industry. The production tax credit of 2.2 cents per kilowatt was renewed, which has the effect of making wind power more competitive with cheap fossil fuels.
Even working within the more restrictive context of previous bills, wind energy is the fastest growing of all renewables. Among all energy sources, it is second only to natural gas in terms of added capacity in recent years. Wind represented 32% of the electrical-generation capacity added in 2011, with approximately 6.8 gigawatts of new capacity and $14 billion invested. As of that year, wind generated nearly 3% of the country’s electricity, second among renewable sources only to hydropower, which has shown little growth since the 1970s. And this year wind’s progression has been even more notable: All electrical-generation capacity added in the U.S. in January 2013 was renewable, and more than 75% of that was wind.
As wind energy has grown, so have the number of jobs it provides — 85,000 workers were employed in 2008 and 2009, and the production tax credit’s renewal will now keep many on the job who would otherwise have been laid off. Much of the equipment installed is also built in the United States: According to the Department of Energy, 70% of the equipment at U.S. wind farms was manufactured domestically, double the percentage in 2005.
While there are theoretical and practical limits to the amount of energy that could be extracted from the wind, the potential is far higher than that currently captured. According to the Department of Energy, untapped offshore wind alone could provide four times the nation’s current generation capacity. While land-based wind has lagged up to now, a wide range of new projects are under study and development, including Cape Wind in Massachusetts. The project was awarded a 15-year contract to provide the local utility with more than a quarter of its power, and officially broke ground in August 2012 at its New Bedford production facility.
To grow consistently, analysts say, what’s needed is stable regulatory context, something currently lacking in the United States. The booms and busts have been driven by the erratic extension and expiration of the production tax credit — in large part 2012’s banner year, with 12 gigawatts of new capacity, was driven by the fear that Congress wouldn’t renew the credit: Projects had to be completed and online by the end of the year or they wouldn’t qualify. In a step forward, the wind-energy provision in the “fiscal cliff” deal only requires that projects start construction in 2013, not go on-line, to receive the credit.
Research indicates that the long-term prospects for wind are significant. A study commissioned by the Department of Energy determined that wind will generate 20% of the nation’s electricity by 2030. Looking farther ahead, a 2009 Harvard study calculated that even under conservative assumptions, a combination of onshore and offshore wind could generate 16 times current domestic electrical consumption. And a study in PNAS, “Saturation Wind Power Potential and Its Implications for Wind Energy,” determined that “there is no fundamental barrier to obtaining half (approximately 5.75 TW) or several times the world’s all-purpose power from wind in a 2030 clean-energy economy.”
The following reports and studies provide further perspective:
Platzer, Michaela D. Congressional Research Service, December 2012.
Summary: “About 470 U.S. manufacturing facilities produced wind turbines and components in 2011, up from as few as 30 in 2004. An estimated 30,000 U.S. workers were employed in the manufacturing of wind turbines in 2011. Because turbine blades,
towers, and certain other components are large and difficult to transport, manufacturing clusters have developed in certain states, notably Colorado, Iowa, and Texas, which offer proximity to the best locations for wind energy production. The U.S. wind turbine manufacturing industry also depends on imports, with the majority coming from European countries, where the technical ability to produce large wind turbines was developed. Although turbine manufacturers’ supply chains are global, recent investments are estimated to have raised the share of parts manufactured in the United States to 67% in 2011, up from 35% in 2005-2006.”
Wiser, Robert; Bolinger, Mark; et al. U.S. Department of Energy, Lawrence Berkeley National Laboratory, 2011.
Conclusion: “Regardless of future uncertainties, wind power capacity additions over the past several years, as well as the additions predicted for 2012, have put the United States on a trajectory that may lead to 20% of the nation’s electricity demand coming from wind energy by 2030. In May 2008, the U.S. Department of Energy, in collaboration with its national laboratories, the wind power industry, and others, published a report that analyzed the technical and economic feasibility of achieving 20% wind energy penetration by 2030 (DOE 2008)…. Historical growth over the last six years puts the United States on a trajectory exceeding this deployment path, a trend that is anticipated to continue in 2012.”
Hahn, Michael; Gilman, Patrick. U.S. Department of Energy, Navigant, November 2012.
Conclusion: “Policy examples from other countries have shown that proper policy designs can stimulate offshore wind markets, and in turn, offshore wind markets can have a significant impact on economic development throughout the U.S. The analysis showed that in the high-growth scenario, the U.S. offshore wind industry could support [approximately] 350,000 FTEs in 2030, and 50,000 FTEs in the low-growth scenario. Policies that can direct the market toward the higher growth scenario can therefore have a large benefit to the U.S. economy.”
Lu, Xi; McElroy, Michael B.; Kiviluomac, Juha. PNAS, July 2009, Vol. 106, No. 27. doi: 10.1073/pnas.0904101106
Abstract: “The potential of wind power as a global source of electricity is assessed by using winds derived through assimilation of data from a variety of meteorological sources. The analysis indicates that a network of land-based 2.5-megawatt (MW) turbines restricted to nonforested, ice-free, nonurban areas operating at as little as 20% of their rated capacity could supply >40 times current worldwide consumption of electricity, >5 times total global use of energy in all forms. Resources in the contiguous United States, specifically in the central plain states, could accommodate as much as 16 times total current demand for electricity in the United States. Estimates are given also for quantities of electricity that could be obtained by using a network of 3.6-MW turbines deployed in ocean waters with depths <200 m within 50 nautical miles (92.6 km) of closest coastlines.”
Jacobson, Mark Z.; Archer, Cristina L. PNAS, September 2012, Vol. 109, No. 39. doi: 10.1073/pnas.1208993109.
Abstract: “Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. As the number of wind turbines increases over large geographic regions, power extraction first increases linearly, but then converges to a saturation potential not identified previously from physical principles or turbine properties. These saturation potentials are >250 terawatts (TW) at 100 m globally, approximately 80 TW at 100 m over land plus coastal ocean outside Antarctica, and approximately 380 TW at 10 km in the jet streams.”
Adams, Amanda S.; Keith, David W. Environmental Research Letters, 2013. doi:10.1088/1748-9326/8/1/015021.
Abstract: “Estimates of the global wind power resource over land range from 56 to 400 TW. Most estimates have implicitly assumed that extraction of wind energy does not alter large-scale winds enough to significantly limit wind power production. Estimates that ignore the effect of wind turbine drag on local winds have assumed that wind power production of [2 to 4 watts per square meter] can be sustained over large areas. New results from a mesoscale model suggest that wind power production is limited to about [1 watt per square meter] at wind farm scales larger than about 100 km2.”
Tags: renewable energy, research roundup