# 20% Wind Energy by 2030

Increasing Wind Energy’s Contribution to U.S. Electricity Supply

DOE/GO-102008-2578 **•** Dec ember 2008

More information is available on the web at:

www.eere.energy.gov/windandhydro http://www.nrel.gov/docs/fy08osti/41869.pdf



# December 2008GRATEFUL APPRECIATION TO PARTNERS

The U.S. Department of Energy would like to acknowledge the in-depth analysis and extensive research conducted by the National Renewable Energy Laboratory and the major contributions and manuscript reviews by the American Wind Energy Association and many wind industry organizations that contributed to the production of this report. The costs curves for energy supply options and the WinDS modeling assumptions were developed in cooperation with Black & Veatch. The preparation of this technical report was coordinated by Energetics Incorporated of Washington, DC and Renewable Energy Consulting Services, Inc. of Palo Alto, CA.

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Printed on paper containing at least 50% wastepaper, including 20% postconsumer waste**20% Wind Energy by 2030: Executive Summary** 1 

# Executive Summary & Overview

I NTRODUCTION AND 

# C OLLABORATIVE 

# A PPROACH

Energy prices, supply uncertainties, and environmental concerns are driving the United States to rethink its energy mix and develop diverse sources of clean, renewable energy. The nation is working toward generating more energy from domestic resources—energy that can be cost-effective and replaced or “renewed” without contributing to climate change or major adverse environmental impacts.

In 2006, President Bush emphasized the nation’s need for greater energy efficiency and a more diversified energy portfolio. This led to a collaborative effort to explore a modeled energy scenario in which wind provides 20% of U.S. electricity by 2030. Members of this 20% Wind collaborative (see 20% Wind Scenario sidebar) produced this report to start the discussion about issues, costs, and potential outcomes

associated with the 20% Wind Scenario. A 20% Wind Scenario in 2030, while ambitious, could be feasible if the significant challenges identified in this

report are overcome.

This report was prepared by DOE in a joint effort with industry, government,

and the nation’s national laboratories (primarily the National Renewable Energy Laboratory and Lawrence Berkeley National Laboratory). 1 The report considers some associated challenges, estimates the impacts, and discusses specific needs and outcomes in the areas of technology, manufacturing and employment, transmission and grid integration, markets, siting strategies, and potential environmental effects associated with a 20% Wind Scenario.

In its Annual Energy Outlook 2007, the U.S. Energy Information Administration (EIA) estimates that U.S. electricity demand will grow by 39% from 2005 to 2030,

1 This is the executive summary of the full report entitled 20% Wind Energy by 2030: Increasing Wind Energy’s Contribution to U.S. Electricity Supply , available at www.nrel.gov/docs/fy08osti/41869.pdf

. Chapters and appendices referenced herein can be found in the full report. 

## 20% Wind Scenario: Wind Energy Provides 20% of U.S. Electricity Needs by 2030

Key Issues to Examine:

**•** Does the nation have sufficient wind energy

resources?

**•** What are the wind technology requirements?

**•** Does sufficient manufacturing capability exist?

**•** What are some of the key impacts?

**•** Can the electric network accommodate 20% wind?

**•** What are the environmental impacts?

**•** Is the scenario feasible?



### Assessment Participants:

**•** U.S. Department of Energy (DOE)

− Office of Energy Efficiency and Renewable Energy (EERE), Office of Electricity Delivery and Energy Reliability (OE), and Power Marketing Administrations (PMAs)

− National Renewable Energy Laboratory (NREL)

− Lawrence Berkeley National Laboratory (Berkeley Lab)

− Sandia National Laboratories (SNL)

**•** Black & Veatch engineering and consulting firm

**•** American Wind Energy Association (AWEA)

− Leading wind manufacturers and suppliers

− Developers and electric utilities

− Others in the wind industry2 **20% Wind Energy by 2030: Executive Summary** reaching 5.8 billion megawatt-hours (MWh) by 2030. To meet 20% of that demand, U.S. wind power capacity would have to reach more than 300 gigawatts (GW) or more than 300,000 megawatts (MW). This growth represents an increase of more than 290 GW within 23 years. 2

The data analysis and model runs for this report were concluded in mid-2007. All data and information in the report are based on wind data available through the end of 2006. At that time, the U.S. wind power fleet numbered 11.6 GW and spanned 34 states. In 2007, 5,244 MW of new wind generation were installed. 3 With these additions, American wind plants are expected to generate an estimated 48 billion kilowatt-hours (kWh) of wind energy in 2008, more than 1% of U.S. electricity supply. This capacity addition of 5,244 MW in 2007 exceeds the more conservative growth trajectory developed for the 20% Wind Scenario of about 4,000 MW/year in 2007 and 2008. The wind industry is on track to grow to a size capable of installing 16,000 MW/year, consistent with the latter years in the 20% Wind Scenario, more quickly than the trajectory used for this analysis.



## S COPE

This report examines some of the costs, challenges, and key impacts of generating 20% of the nation’s electricity from wind energy in 2030. Specifically, it investigates requirements and outcomes in the areas of technology, manufacturing, transmission and integration, markets, environment, and siting.

The modeling done for this report estimates that wind power installations with capacities of more than 300 gigawatts (GW) would be needed for the 20% Wind Scenario. Increasing U.S. wind power to this level from 11.6 GW in 2006 would require significant changes in transmission, manufacturing, and markets. This report presents an analysis of one specific scenario for reaching the 20% level and contrasts it to a scenario of no wind growth beyond the level reached in 2006. Major assumptions in the analysis have been highlighted throughout the document and have been summarized in the appendices. These assumptions may be considered optimistic. In this report, no sensitivity analyses have been done to estimate the impact that changes in the assumptions would have on the information presented here. As summarized at the end of this chapter, the analysis provides an overview of some potential impacts of these two scenarios by 2030. This report does not compare the Wind Scenario to other energy portfolio options, nor does it outline an action plan.

To successfully address energy security and environmental issues, the nation needs to pursue a portfolio of energy options. None of these options by itself can fully address these issues; there is no “silver bullet.” This technical report examines one potential scenario in which wind power serves as a significant element in the portfolio. However, the 20% Wind Scenario is not a prediction of the future. Instead, it paints a picture of what a particular 20% Wind Scenario could mean for the

nation.

2 AEO data from 2007 were used in this report. AEO released new data in March of 2008, which were not incorporated into this report. While the new EIA data could change specific numbers in the report, it would not change the overall message of the report.

3 According to AWEA’s 2007 Market Report of January 2008, the U.S. wind energy industry installed 5,244 MW in 2007, expanding the nation's total wind power generating capacity by 45% in a single calendar year and more than doubling the 2006 installation of 2,454 MW. Government sources for validation of 2007 installations were not available at the time this report was written.**20% Wind Energy by 2030: Executive Summary** 3 

## C ONTRIBUTORS

Report contributors include a broad cross section of key stakeholders, including leaders from the nation’s utility sector, environmental communities, wildlife advocacy groups, energy industries, the government and policy sectors, investors, and public and private businesses. In all, the report reflects input from more than 50 key energy stakeholder organizations and corporations. Appendix D contains a

list of contributors. Research and modeling was conducted by experts within the electric industry, government, and other organizations.

This report is not an authoritative expression of policy perspectives or opinions held by representatives of

DOE.



## A SSUMPTIONS AND 

## P ROCESS

To establish the groundwork for this report, the engineering company Black & Veatch (Overland Park, Kansas) analyzed the market potential for significant wind energy growth, quantified the potential U.S. wind supply, and developed cost supply curves for the wind resource. In consultation with DOE, NREL, AWEA, and wind industry partners, future wind energy cost and performance projections were developed. Similar projections for conventional generation technologies were developed based on Black & Veatch experience with power plant design and construction (Black & Veatch 2007).

To identify a range of challenges, possible solutions, and key impacts of providing 20% of the nation’s electricity from wind, the

stakeholders in the 20% Wind Scenario effort convened expert task forces to examine specific areas critical to this endeavor: Technology and Applications, Manufacturing and 

## Wind Energy Deployment System Model Assumptions (See Appendices A and B)

**•** The assumptions used for the WinDS model were obtained from a number of sources, including technical experts (see Appendix D), the WinDS base case (Denholm and Short 2006), AEO 2007 (EIA 2007), and a study performed by Black & Veatch (2007). These assumptions include projections of future costs and performance for all generation technologies, transmission system expansion costs, wind resources as a function of geographic location within the continental United States, and projected growth rates for wind generation.

**•** Wind energy generation is prescribed annually on a national level in order to reach 20% wind energy by 2030:

− A stable policy environment supports accelerated wind deployment.

− Balance of generation is economically optimized with no policy changes from those in place today (e.g., no production tax credit [PTC] beyond 12/31/08).

− Technology cost and performance assumptions as well as electric grid expansion and operation assumptions that affect the direct electric system cost.

**•** Land-based and offshore wind energy technology cost reductionsand performance improvements are expected by 2030 (see tables A1, B-10, and B-11). Assumes that capital costs would be reduced by 10% over the next two decades and capacity factors would be increased by about 15% (corresponding to a 15% increase in annual energy generation by a wind plant)

**•** Future environmental study and permit requirements do not add significant costs to wind technology.

**•** Fossil fuel technology costs and performance are generally flat between 2005 and 2030 (see tables A-1 and B-13).

**•** Nuclear technology cost reductions are expected by 2030 (see tables A-1 and B-13).

**•** Reserve and capacity margins are calculated at the North American Electric Reliability Corporation (NERC) region level, and new transmission capacity is added as needed (see sections A.2.2 and B.3).

**•** Wind resource as a function of geographic location from various sources (see Table B-8).

**•** Projected electricity demand, financing assumptions, and fuel prices

are based on Annual Energy Outlook (EIA 2007; see sections B.1, B.2, and B.4.2).

**•** Cost of new transmission is generally split between the originating project, be it wind or conventional generation, and the ratepayers within the region.

**•** Ten percent of existing grid capacity is available for wind energy.

**•** Existing long-term power purchase agreements are not implemented in WinDS. The model assumes that local load is met by the generation technologies in a given region.

**•** Assumes that the contributions to U.S. electricity supplies from other renewable sources of energy would remain at 2006 levels in both

scenarios.4 **20% Wind Energy by 2030: Executive Summary** Materials, Environmental and Siting Impacts, Electricity Markets, Transmission and Integration, and Supporting Analysis. These teams conducted in-depth analyses of potential impacts, using related studies and various analytic tools to examine the benefits and costs. (See Appendix D for the task force participants.)

NREL’s Wind Deployment System (WinDS) model 4 was employed to create a scenario that paints a “picture” of this level of wind energy generation and evaluates some impacts associated with wind. Assumptions about the future of the U.S. electric generation and transmission sector were developed in consultation with the task forces and other parties. Some assumptions in this analysis could be considered optimistic. Examples of assumptions used in this analysis are listed in the “Wind Energy Deployment System Model Assumptions” text box and are presented in detail in Appendices A and B. For comparison, the modeling team contrasted the 20% Wind Scenario impacts to a reference case characterized by no growth in U.S. wind capacity or other renewable energy sources after 2006.

In the course of the 20% Wind Scenario process, two workshops were held to define and refine the work plan, present and discuss preliminary results, and obtain relevant input from key stakeholders external to the report preparation effort.



## R EPORT 

## S TRUCTURE

The 20% Wind Scenario in 2030 would require improved turbine technology to generate wind power, significant changes in transmission systems to deliver it through the electric grid, and large expanded markets to purchase and use it. In turn, these essential changes in the power generation and delivery process would involve supporting changes and capabilities in manufacturing, policy development, and environmental regulation. As shown in Figure ES-1, the chapters of this report address some of the requirements and impacts in each of these areas. Detailed discussions of the modeling process, assumptions, and results can be found in Appendices A through C.

Figure ES-1. Report chapters

4 The model, developed by NREL’s Strategic Energy Analysis Center (SEAC), is designed to address the principal market issues related to the penetration of wind energy technologies into the electric sector. For additional information and documentation, see text box entitled “Wind Energy Deployment System Model Assumptions,” Appendices A and B, and http://www.nrel.gov/analysis/winds/

.**20% Wind Energy by 2030: Executive Summary** 5 

## S ETTING THE 

## C ONTEXT 

## : T ODAY 

## ’ S 

## U.S. W IND 

## I NDUSTRY

After experiencing strong growth in the mid-1980s, the U.S. wind industry hit a plateau during the electricity restructuring period in the 1990s and then regained momentum in 1999. Industry growth has since responded positively to policy incentives when they are in effect (see Figure ES-2). Today, the U.S. wind industry is growing rapidly, driven by sustained production tax credits (PTCs), rising concerns about climate change, and renewable portfolio standards (RPS) or goals in roughly 50% of the states.

U.S. turbine technology has advanced steadily to offer improved performance, and these efforts are expected to continue (see “Initiatives to Improve Wind Turbine Performance” sidebar). In 2006 alone, average turbine size increased by more than 11%

over the 2005 level to an average size of 1.6 MW. In addition, average capacity factors have improved 11% over the past two years. To meet the growing demand for wind energy, U.S. manufacturers have expanded their capacity to produce and assemble the essential components. Despite this growth, U.S. components continue to represent a relatively small share of total turbine and tower materials, and U.S. manufacturers are struggling to keep pace with rising demand (Wiser & Bolinger 2007). Figure ES-2. Cumulative U.S. wind capacity, by year

(in megawatts [MW])



## Initiatives to Improve Wind Turbine Performance

Avoid problems before installation

**•** Improve reliability of turbines and components

**•** Full-scale testing prior to commercial introduction

**•** Development of appropriate design criteria, specifications, and standards

**•** Validation of design tools



### Monitor performance

**•** Monitor and evaluate turbine and wind-plant performance

**•** Performance tracking by independent parties

**•** Early identification of problems



### Rapid deployment of problem resolution

**•** Develop and communicate problem solutions

**•** Focused activities with stakeholders to address critical issues (e.g., Gearbox Reliability Collaborative)6 **20% Wind Energy by 2030: Executive Summary** In 2005 and 2006, the United States led the world in new wind installations. By early 2007, global wind power capacity exceeded 74 GW, and U.S. wind power capacity totaled 11.6 GW. This domestic wind power has been installed across 35 states and delivers roughly 0.8% of the electricity consumed in the nation (Wiser and Bolinger 2007).



## A Brief History of the U.S. Wind Industry

The U.S. wind industry got its start in California during the 1970s, when the oil shortage increased the price of electricity generated from oil. The California wind industry benefited from federal and state ITCs as well as state-mandated standard utility contracts that guaranteed a satisfactory market price for wind power. By 1986, California had installed more than 1.2 GW of wind power, representing nearly 90% of global installations at that time.

Expiration of the federal ITC in 1985 and the California incentive in 1986 brought the growth of the U.S. wind energy industry to an abrupt halt in the mid-1980s. Europe took the lead in wind energy, propelled by aggressive renewable energy policies enacted between 1974 and 1985. As the global industry continued to grow into the 1990s, technological advances led to significant increases in turbine power and productivity. Turbines installed in 1998 had anaverage capacity 7 to 10 times greater than that of the 1980s turbines, and the price of windgenerated electricity dropped by nearly 80% (AWEA 2007). By 2000, Europe had more than 12,000 MW of installed wind power, versus only 2,500 MW in the United States, and Germany became the new international leader.

With low natural gas prices and U.S. utilities preoccupied by industry restructuring during the 1990s, the federal production tax credit (PTC) enacted in 1992 (as part of the Energy Policy Act [EPAct]) did little to foster new wind installations until just before its expiration in June 1999. Nearly 700 MW of new wind generation were installed in the last year before the credit expired—more than in any previous 12-month period since 1985. After the PTC expired in 1999, it was extended for two brief periods, ending in 2003. It was then reinstated in late 2004. Although this intermittent policy support led to sporadic growth, business inefficiencies inherent in serving this choppy market inhibited investment and restrained market growth.

To promote renewable energy systems, many states began requiring electricity suppliers to obtain a small percentage of their supply from renewable energy sources, with percentages typically increasing over time. With Iowa and Texas leading the way, more than 20 states have followed suit with RPSs, creating an environment for stable growth.

After a decade of trailing Germany and Spain, the United States reestablished itself as the world leader in new wind energy in 2005. This resurgence is attributed to increasingly supportive policies, growing interest in renewable energy, and continued improvements in wind technology and performance. The United States retained its leadership of wind development in 2006 and, because of its very large wind resources, is likely to remain a major force in the highly competitive wind markets of the future. 

### Energy Policy Act of

1992

The PTC gave power producers 1.5 cents (increased annually with inflation) for every kilowatt-hour (kWh) of electricity produced from wind during the first 10 years of operation.**20% Wind Energy by 2030: Executive Summary** 7 

# S CENARIO 

# D ESCRIPTION

The 20% Wind Scenario presented here would require U.S. wind power capacity to grow from 11.6 GW in 2006 to more than 300 GW over the next 23 years (see Figure ES-3). This ambitious growth could be achieved in many different ways, with varying challenges, impacts, and

levels of success. The 20% Wind Scenario would require an installation rate of 16 GW per year after 2018 (see Figure ES-4). This report examines one particular scenario for achieving this dramatic growth and

contrasts it to another scenario that— for analytic simplicity—assumes no wind growth after 2006. The authors recognize that U.S. wind capacity is currently growing rapidly (although from a very small base) and that wind energy technology will be a part of any future electricity generation

scenario for the United States. At the same time, a great deal of uncertainty remains about the level of contribution that wind could or is likely to make. In the

2007 Annual Energy Outlook (EIA 2007), an additional 7 GW beyond the 2006 installed capacity of 11.6 GW is forecast by 2030. 5 Other organizations are projecting higher capacity additions, and it would be difficult to develop a “most likely” forecast given today’s uncertainties. The analysis presented here sidesteps these uncertainties and contrasts some of the challenges and impacts of producing 20% of the nation’s electricity from wind with a scenario in which no additional wind is added after 2006. This results in an estimate, expressed in terms of parameters, of the impacts associated with increased reliance on wind energy generation under given assumptions. The analysis was also simplified by assuming that the

contributions to U.S. electricity supplies

from other

renewable sources of energy would remain

at 2006 levels in both scenarios (see Figure A-6 for resource mix).

The 20% Wind

Scenario has been carefully defined to provide a base of

5 AEO data from 2007 were used in this report. AEO released new data in March 2008, which were not incorporated into this report. While new EIA data could change specific numbers in this report, it would not change the overall message of the report. Figure ES-3. Required growth in U.S. capacity (GW) to implement the
20% Wind Scenario

Figure ES-4. Annual and cumulative wind installations by 20308 **20% Wind Energy by 2030: Executive Summary** common assumptions for detailed analysis of all impact areas. Broadly stated, this 20% scenario is designed to consider incremental costs while recognizing realistic constraints and considerations (see the “Considerations in the 20% Wind Scenario” sidebar in Appendix A). Specifically, the scenario describes the mix of wind resources that would need to be captured, the geographic distribution of wind power installations, estimated land needs, the required utility and transmission infrastructure, manufacturing requirements, and the pace of growth that would be

necessary.



## W IND 

## G EOGRAPHY

The United States possesses abundant wind resources. As shown in Figure ES-5, current “bus-bar” energy costs for wind (based on costs of the wind plant only, excluding transmission and integration costs and the PTC) vary by type of location (land-based or offshore) and by class of wind power density (higher classes offer greater productivity). Transmission and integration will add additional costs, whichare discussed in Chapter 4. The nation has more than 8,000 GW of available landbased wind resources (Black & Veatch 2007) that industry estimates can be captured economically. NREL periodically classifies wind resources by wind speed, which forms the basis of the Black & Veatch study. See Appendix B for further details.

Electricity must be transmitted from where it is generated to areas of high electricity demand, using the existing transmission system or new transmission lines where necessary. As shown in Figure ES-6, the delivered cost of wind power increases when costs associated with connecting to the existing electric grid are included. The assumptions used in this report are different than EIA’s assumptions and are documented in Appendices A and B. The cost and performance assumptions of the 20% Wind Scenario are based on real market data from 2007. Cost and performance for all technologies either decrease or remain flat over time. The data suggest that as

Figure ES-5. Supply curve for wind energy—current bus-bar energy costs

Note: See Appendix B for wind technology cost and performance projections; PTC and transmission and integration

costs are excluded.**20% Wind Energy by 2030: Executive Summary** 9 much as 600 GW of wind resources could be available for $60 to $100 per megawatt-hour (MWh), including the cost of connecting to the existing transmission system. Including the PTC reduces the cost by about $20/MWh, and costs are further reduced if technology improvements in cost and performance are projected. In some cases, new transmission lines connecting high-wind resource areas to load centers could be cost-effective, and in other cases, high transmission costs could offset the advantage of land-based generation, as in the case of large demand centers along

wind-rich coastlines.

NREL’s WinDS model estimated the overall U.S. generation capacity expansion that is required to meet projected electricity demand growth through 2030. Both wind technology and conventional generation technology (i.e., coal, nuclear) were included in the modeling, but other renewables were not included. Readers should refer to Appendices A and B to see a more complete list of the modeling assumptions. Wind energy development for the 20% Wind Scenario optimized the total delivered costs, including future reductions in cost per kilowatt-hour for wind sites both near to and remote from demand sites from 2000 through 2030. 6 Chapter 2 presents additional discussion of wind technology potential. Of the 293 GW that would be added, the model specifies more than 50 GW of offshore wind energy (see Figure ES-7), mostly along the northeastern and southeastern seaboards.

6 The modeling assumptions prescribed annual wind energy generation levels that reached 20% of projected demand by 2030 so as to demonstrate technical feasibility and quantify costs and impacts. Policy options that would help induce this growth trajectory were not included. It is assumed that a stable policy environment that recognizes wind’s benefits could lead to growth rates that would result

in the 20% Wind Scenario. Figure ES-6. Supply curve for wind energy—energy costs including connection to 10% of existing transmission grid capacity

Note: See Appendix B for wind technology cost and performance projections. Excludes PTC, includes transmission costs to access existing electric transmission within 500 miles of wind resource.10 **20% Wind Energy by 2030: Executive Summary** Based on this least-cost optimization algorithm (which incorporatesfuture cost per kilowatthour of wind and cost of transmission), the

WinDS model estimated the wind capacity needed by state by 2030. As shown in Figure ES-8,

most states would have the opportunity to develop their wind

resources. Total land requirements are extensive, but only about

2% to 5% of the total

would be dedicated entirely to the wind installation. In addition, the visual impacts and other siting concerns of wind energy projects must be taken into account in assessing land requirements. Chapter 5 contains additional discussion of land use and visual impacts. Again, the 20% Wind Scenario presented here is not a prediction. Figure ES-8 simply shows one way in which a 20% wind future could

evolve. Figure ES-7. 20% cumulative installed wind power capacity required to produce 20% of projected electricity by 2030

Figure ES-8. 46 states would have substantial wind development by 2030

Wind capacity levels in each state depend on a variety of assumptions and the national optimization of electricity generation expansion. Based on the perspectives of industry experts and near-term wind development plans, wind capacity in Ohio was modified and offshore wind development in Texas was included. In reality, each state’s wind capacity level will vary significantly as electricity markets evolve and state policies promote or restrict the energy production of electricity from wind and other renewable and conventional energy sources. The 20% Wind Scenario

envisions 251 GW of

land-based and 54 GW

of shallow offshore wind capacity to optimize delivered costs, which include both generation

and transmission. Land Requirements

Altogether, new landbased installations would require approximately 50,000 square kilometers (km 2 ) of land, yet the actual footprint of land-based

turbines and related

infrastructure would require only about 1,000 to 2,500 km 2 of dedicated land—slightly
less than the area of

Rhode Island.**20% Wind Energy by 2030: Executive Summary** 11 

## W IND 

## P OWER 

## T RANSMISSION AND 

## I NTEGRATION

Development of 293 GW of new wind capacity would require expanding the U.S. transmission grid in a manner that not only accesses the best wind resource regions of the country but also relieves current congestion on the grid, including new transmission lines to deliver wind power to electricity consumers. Figure ES-9 conceptually illustrates the optimized use of wind resources within the local areas as well as the transmission of wind-generated electricity from high-resource areas to high-demand centers. This data was generated by the WinDS model (given prescribed constraints). The figure does not represent proposals for specific

transmission lines.

Figure ES-10 displays transmission needs in the form of one technically feasible transmission grid as a 765 kV overlay. A complete discussion of transmission issues can be found in Chapter 4.

Until recently, concerns had been prevalent in the electric utility sector about the difficulty and cost of dealing with the variability and uncertainty of energy production from wind plants and other weather-driven renewable technologies. But utility engineers in some parts of the United States now have extensive experience with wind plant impacts, and their analyses of these impacts have helped to reduce these concerns. As discussed in detail in Chapter 4, wind’s variability is being accommodated, and given optimistic assumptions, studies suggest the cost impact could be as little as the current level—10% or less of the value of the wind energy generated. Figure ES-9. All new electricity generation including wind energy would require expansion of U.S. transmission by 203012 **20% Wind Energy by 2030: Executive Summary** 

## E LECTRICAL 

## E NERGY 

## M IX

The U.S. Energy Information Administration (EIA) estimates that U.S. electricity demand will grow by 39% from 2005 to 2030, reaching 5.8 billion MWh by 2030. The 20% Wind Scenario would require delivery of nearly 1.16 billion MWh of wind energy in 2030, altering U.S. electricity generation as shown in Figure ES-11. In this scenario, wind would supply enough energy to displace about 50% of electric utility natural gas consumption and 18% of coal consumption by 2030. This amounts to an 11% reduction in natural gas across all industries. (Gas-fired generation would probably be displaced first, because it typically has a higher cost.)

The increased wind development in this scenario

could reduce the need for new coal and combined cycle natural gas capacity, but would increase the need for additional combustion turbine natural gas capacity to maintain electric system reliability. These units, though, would be run only as

needed. 7



## P ACE OF 

## N EW 

## W IND 

## I NSTALLATIONS

Manufacturing capacity would require time to ramp up enough to support rapid growth in new

U.S. wind installations. The 20% Wind Scenario

7 Appendix A presents a full analysis of changes in the capacity mix and energy generation under the

20% Wind Scenario. Figure ES-10. Conceptual transmission plan to accommodate 400 GW of wind energy (AEP 2007)

Figure ES-11. U.S. electrical energy mix**20% Wind Energy by 2030: Executive Summary** 13 estimates that the installation rate would need to increase from installing 3 GW per year in 2006 to more than 16 GW per year by 2018 and to continue at roughly that rate through 2030, as seen in Figure ES-4. This increase in installation rate, although quite large, is comparable to the recent annual installation rate of natural gas units,

which totaled more than 16 GW in 2005 alone (EIA 2005).

The assumptions of the 20% Wind

Scenario form the foundation for the technical analyses presented in the remaining chapters. This overview is provided as context for the potential impacts and technical challenges

discussed in the next sections.



# I MPACTS

The 20% Wind Scenario presented here offers potentially positive impacts in terms of greenhouse gas (GHG) reductions, water conservation, and energy security, as compared to the base case of no wind growth in this analysis. However, tapping this resource at this level would entail large front-end capital investments to install wind capacity and expanded transmission systems. The impacts

described in this section are based largely on the analytical tools and methodology discussed in detail in Appendices A, B, and C.

Wind power would be a critical part of a broad and near-term strategy to substantially reduce air pollution, water pollution, and global climate change associated with traditional generation technologies (see “Wind vs. Traditional Electricity Generation” sidebar). As a domestic energy resource, wind power would also stabilize and diversify national energy supplies.



## G REENHOUSE 

## G AS 

## R EDUCTIONS

Supplying 20% of U.S. electricity from wind could reduce annual electric sector carbon dioxide (CO 2 ) emissions by 825 million metric tons by 2030. 

## 20% Wind Scenario: Projected Impacts

**•** Environment: Avoids air pollution and reduces GHG emissions; reduces electric sector CO 2 emissions by 825 million metric tons annually

**•** Water savings: Reduces cumulative water use in the electric sector by 8% (4 trillion gallons)

**•** U.S. energy security: Diversifies electricity portfolio and represents an indigenous energy source with stable prices not subject to fuel volatility

**•** Energy consumers: Potentially reduces demand for fossil fuels, in turn reducing fuel prices and stabilizing electricity rates

**•** Local economics: Creates new income source for rural

landowners and tax revenues for local communities in wind development areas

**•** American workers: Generates well-paying jobs in sectors that support wind development, such as manufacturing, engineering, construction, transportation, and financial services; new manufacturing will cause significant growth in wind industry supply chain (see Appendix C) 

## Wind vs. Traditional Electricity Generation

Wind power avoids several of the negative effects of traditional electricity generation from fossil fuels:

**•** Emissions of mercury or other heavy metals into the air

**•** Emissions associated with extracting and transporting

fuels

**•** Lake and streambed acidification from acid rain or mining

**•** Water consumption associated with mining or electricity generation

**•** Production of toxic solid wastes, ash, or slurry

**•** Greenhouse gas (GHG) emissions14 **20% Wind Energy by 2030: Executive Summary** The threat of climate change and the growing attention paid to it are helping to position wind power as an increasingly attractive option for new power generation. U.S. electricity demand is growing rapidly, and cleaner power sources (e.g., renewable energy) and energy-saving practices (i.e., energy efficiency) could help meet much of the new demand while reducing GHG emissions. Today, wind energy represents approximately 35% of new capacity additions (AWEA 2008). Greater use of wind energy, therefore, presents an opportunity for reducing emissions today as the nation develops additional clean power options for

tomorrow.

Concerns about climate change have spurred many industries, policy makers, environmentalists, and utilities to call for reductions in GHG emissions. Although the cost of reducing emissions is uncertain, the most affordable near-term strategy likely involves wider deployment of currently available energy efficiency and clean energy technologies. Wind power is one of the potential supply-side solutions to the climate change problem (Socolow and Pacala 2006).

Governments at many levels have enacted policies to actively support clean electricity generation, including the renewable energy PTC and state RPS. A growing number of energy and environmental organizations are calling for expanded wind and other renewable power deployment to try to reduce society’s carbon footprint.

According to EIA, The United States annually emits approximately 6,000 million metric tons of CO 2. These emissions are expected to increase to nearly 7,900 million metric tons by 2030, with the electric power sector accounting for approximately 40% of the total (EIA 2007). As shown in Figure ES-12, based on the analysis completed for this report, generating 20% of U.S. electricity from wind could avoid approximately 825 million metric tons of CO 2 emissions in the electric sector in

2030. The 20% Wind Scenario would also reduce cumulative emissions from the electric sector through that same year by more than 7,600 million metric tons of CO 2 (2,100 million metric tons of carbon equivalent). 8 See Figures ES-12 and ES-13 . In general, CO 2 emission reductions are not only a wind energy benefit but could be achieved under other energy-mix scenarios.

The Fourth Assessment Report of the United Nations Environment Program and World Meteorological Organization’s Intergovernmental Panel on Climate Change (IPCC) notes that “Renewable energy generally has a positive effect on energy

8 CO 2 can be converted to carbon equivalent by multiplying by 12/44. Appendix A presents results in carbon equivalent, not CO 2. Because it assumes a higher share of coal-fired generation, the WinDS model projects higher CO 2 emissions than the EIA model

. 

## GHG Reduction

Under the 20% Wind Scenario, a cumulative total of 7,600 million

metric tons of CO 2 emissions would be avoided by 2030, and more than 15,000 million metric tons of CO 2 emissions would be avoided through

2050. 

## 20% Wind Scenario: Major Challenges

**•** Investment in the nation’s transmission system, so that the power generated is delivered to urban centers that need the increased supply;

**•** Larger electric load balancing areas, in tandem with better regional planning, so that regions can depend on a diversity of generation sources, including wind power;

**•** Continued reduction in wind capital costs and improvement in turbine performance through technology advancement and improved manufacturing capabilities;

and

**•** Addressing potential concerns about local siting, wildlife, and environmental issues within the context of generating electricity.**20% Wind Energy by 2030: Executive Summary** 15 security, employment, and air quality. Given costs relative to other supply options, renewable electricity can have a 30% to 35% share of the total electricity supply in 2030. Deployment of low-GHG (greenhouse gas) emission technologies would be required for achieving stabilization and cost reductions” (IPCC 2007).

More than 30 U.S. states have created climate action plans. In addition, the Regional Greenhouse Gas Initiative (RGGI) is a 10-state collaborative in the Northeast to

address CO 2 emissions. All of these state and regional efforts include wind energy as part of a portfolio strategy to reduce overall emissions from energy production (RGGI 2006). Figure ES-12. Annual CO 2 emissions avoided (vertical bars) would reach 825 million metric tons by 2030

Figure ES-13. CO 2 emissions from the electricity sector The cumulative

avoided emissions by

2030 would total 7,600

million metric

tons.16 **20% Wind Energy by 2030: Executive Summary** Because wind turbines typically have a service life of at least 20 years and transmission lines can last more than 50 years, investments in achieving 20% wind power by 2030 could continue to supply clean energy through at least 2050. As a result, the cumulative climate change impact of achieving 20% wind power could grow to more than 15,000 million metric tons of CO 2 emissions avoided by midcentury (4,182 million metric tons of carbon equivalent).

The 20% Wind Scenario constructed here would displace a significant amount of fossil fuel generation. According to the WinDS model, by 2030, wind generation is projected to displace 50% of electricity generated from natural gas and 18% of that generated from coal. The displacement of coal is of particular interest because it provides a comparatively higher carbon emissions reduction opportunity. Recognizing that coal power will continue to play a major role in future electricity generation, a large increase in total wind capacity could potentially defer the need to build some new coal capacity, avoiding or postponing the associated increases in carbon emissions. Current DOE projections anticipate construction of approximately 140 GW of new coal plant capacity by 2030 (EIA 2007); the 20% Wind Scenario could avoid construction of more than 80 GW of new coal capacity. 9

Wind energy that displaces fossil fuel generation can also help meet existing regulations for emissions of conventional pollutants, including sulfur dioxide, nitrogen oxides, and mercury.



## W ATER 

## C ONSERVATION

The 20% scenario would potentially reduce cumulative water consumption in the electric sector by 8% (or 4 trillion gallons) from 2007 through 2030—significantly reducing water consumption in the arid states of the interior West. In 2030, annual water consumption in the electric sector would be reduced by 17%.

Water scarcity is a significant problem in many parts of the United States. Even so, few U.S. citizens realize that electricity generation accounts for nearly 50% of all water withdrawals in the nation, with irrigation withdrawals coming in second at 34% (USGS 2005). Water is used for the cooling of natural gas, coal, and nuclear power plants and is an increasing part of the challenge in developing those

resources.

Although a significant portion of the water withdrawn for electricity production is recycled back through the system, approximately 2% to 3% of the water withdrawn is consumed through evaporative losses. Even this small fraction adds up to approximately 1.6 to 1.7 trillion gallons of water consumed for power generation each year.

As additional wind generation displaces fossil fuel generation, each megawatt-hour generated by wind could save as much as 600 gallons of water that would otherwise

9 Carbon mitigation policies were not modeled in either the 20% Wind or No New Wind Scenarios, which results in conventional generation mixes typical of current generation capacity. Under carbon mitigation scenarios, additional technologies could be implemented to reduce the need for conventional generation technology (see Appendix A). 

## Wind Reduces Vulnerability

Continued reliance on natural gas for new power generation is likely to put the United States in growing competition in world markets for liquefied natural gas (LNG)—some of which will come from Russia, Qatar,Iran, and other nations in less-thanstable regions.**20% Wind Energy by 2030: Executive Summary** 17 be lost to fossil plant cooling. 10 Because wind energy generation uses a negligible amount of water, the 20% Wind Scenario would avoid the consumption of 4 trillion gallons of water through 2030, a cumulative reduction of 8%, with annual reductions through 2030 shown in Figure ES-14. The annual savings in 2030 is approximately 450 billion gallons. This savings would reduce the expected annual water consumption for electricity generation in 2030 by 17%. The projected water savings are dependent on a future generation mix, which is discussed further in Appendix A.

Based on the WinDS modeling results, nearly 30% of the projected water savings from the 20% Wind Scenario would occur in western states, where water resources are particularly scarce. The Western Governors Association (WGA) highlights this concern in its Clean and Diversified Energy Initiative, which recognizes increased water consumption as a key challenge in accommodating rapid growth in electricity demand. In its 2006 report on water needs, the WGA states that “difficult political choices will be necessary regarding future economic and environmental uses of water and the best way to encourage the orderly transition to a new equilibrium” (WGA 2006).



## E NERGY 

## S ECURITY AND 

## S TABILITY

There is broad and growing recognition that the nation should diversify its energy portfolio so that a supply disruption affecting a single energy source will not significantly disrupt the national economy. Developing domestic energy sources with known and stable costs would significantly improve U.S. energy stability and security.

When electric utilities have a Power Purchase Agreement or own wind turbines, the price of energy is expected to remain relatively flat and predictable for the life of the wind project, given that there are no fuel costs and assuming that the machines are well maintained. In contrast, a large part of the cost of coal- and gas-fired electricity is in the fuel, for which prices are often volatile and unpredictable. Fuel price risks reduce security and stability for U.S. manufacturers and consumers, as well as for the U.S. economy as a whole. Even small reductions in the amount of energy available or changes in the price of fuel can cause large economic disruptions across the nation. This capacity to disrupt was clearly illustrated by the 1973 embargo imposed by the Organization of Arab Petroleum Exporting Countries (the “Arab oil embargo”); the 2000–2001 California electricity market problems; and the gasoline

10 See Appendix A for specific assumptions. Figure ES-14. National water savings from the 20% Wind Scenario18 **20% Wind Energy by 2030: Executive Summary** and natural gas shortages and price spikes that followed the 2005 hurricane damage to oil refinery and natural gas processing facilities along the Gulf Coast.

Using wind energy increases security and stability by diversifying the national electricity portfolio. Just as those investing for retirement are advised to diversify investments across companies, sectors, and stocks and bonds, diversification of electricity supplies helps distribute the risks and stabilize rates for electricity

consumers.

Wind energy reduces reliance on foreign energy sources from politically unstable regions. As a domestic energy source, wind requires no imported fuel, and the turbine components can be either produced on U.S. soil or imported from any friendly nation with production capabilities.

Energy security concerns for the electric industry will likely increase in the foreseeable future as natural gas continues to be a leading source of new generation supply. With declining domestic natural gas sources, future natural gas supplies are expected to come in the form of liquefied natural gas (LNG) imported on tanker ships. U.S. imports of LNG could quadruple by 2030 (EIA 2007). Almost 60% of uncommitted natural gas reserves are in Iran, Qatar, and Russia. These countries, along with others in the Middle East, are expected to be major suppliers to the global LNG market. Actions by those sources can disrupt international energy markets and thus have indirect adverse effects on our economy. Additional risks arise from competition for these resources caused by the growing energy demands of China, India, and other developing nations. According to the WinDS model results, under the 20% Wind Scenario, wind energy could displace approximately 11% of natural gas consumption, which is equivalent to 60% of expected LNG imports in 2030. 11
This displacement would reduce the nation’s energy vulnerability to uncertain natural gas supplies. See Appendix A for gas demand reduction assumptions and

calculations.

Continued reliance on fossil energy sources exposes the nation to price risks and supply uncertainties. Although the electric sector does not rely heavily on petroleum, which represents one of the nation’s biggest energy security threats, diversifying the electric generation mix with increased domestic renewable energy would still enhance national energy security by increasing energy diversity and price stability.



## C OST OF THE 

## 20% W IND 

## S CENARIO

The overall economic cost of the 20% Wind Scenario accrues mainly from the incremental costs of wind energy relative to other generation sources. This is impacted by the assumptions behind the scenario, listed in Table A-1. Also, some incremental transmission would be required to connect wind to the electric power system. This transmission investment would be in addition to the significant investment in the electric grid that will be needed to serve continuing load growth, whatever the mix of new generation. The market cost of wind energy remains higher than that of conventional energy sources in many areas across the country. Inaddition, the transmission grid would have to be expanded and upgraded in windrich areas and across the existing system to deliver wind energy to many demand centers. An integrated approach to expanding the transmission system would need to include furnishing access to wind resources as well as meeting other system needs.

11 Compared to consumption of the high price scenario of EIA (2007), used in this report.**20% Wind Energy by 2030: Executive Summary** 19 Compared to other generation sources, the 20% Wind Scenario entails higher initial capital costs (to install wind capacity and associated transmission infrastructure) in many areas, yet offers lower ongoing energy costs for operations, maintenance, and fuel. Given the optimistic cost and performance assumptions of wind and

conventional energy sources (detailed in Appendix B), the 20% Wind Scenario could require an incremental investment of as little as $43 billion net present value (NPV) more than the base-case scenario involving no new wind power generation(No New Wind Scenario). This would represent less than 0.06 cents (6 onehundredths of 1 cent) per kilowatt-hour of total generation by 2030, or roughly 50cents per month per household. Figure ES-15 shows this cost comparison. The basecase costs are calculated under the assumption of no major changes in fuel availability or environmental restrictions. In this scenario, the cost differential would be about 2% of a total NPV expenditure exceeding $2 trillion.

This analysis is intended to identify the incremental cost of pursuing the 20% Wind Scenario. In regions where the capital costs of the 20% Wind Scenario exceed those of building little or no additional wind capacity, the differential could be offset by the operating costs and benefits discussed earlier. For example, even though Figure ES-15 shows that under optimistic assumptions, the 20% Wind Scenario could increase total capital costs by nearly $197 billion, most of those costs would be offset by the nearly $155 billion in decreased fuel expenditures, resulting in a net incremental cost of approximately $43 billion in NPV. These monetary costs do not reflect other potential offsetting positive impacts.

As estimated by the NREL WinDS model, given optimistic assumptions, the specific cost of the proposed transmission expansion for the 20% Wind Scenario is $20 billion in NPV. The actual required grid investment could also involve significant costs for permitting delays, construction of grid extensions to remote areas with wind resources, and investments in advanced grid controls, integration, and training to enable regional load balancing of wind resources.

The total installed costs for wind plants include costs associated with siting and permitting of these plants. It has become clear that wind power expansion would Figure ES-15. Incremental investment cost of 20% wind is modest;
a difference of 2%20 **20% Wind Energy by 2030: Executive Summary** require careful, logical, and fact-based consideration of local and environmental concerns, allowing siting issues to be addressed within a broad risk framework. Experience in many regions has shown that this can be done, but efficient, streamlined procedures will likely be needed to enable installation rates in the range of 16 GW per year. Chapter 5 covers these issues in more detail.



# C ONCLUSION

There are significant costs, challenges, and impacts associated with the 20% Wind Scenario presented in this report. There are also substantial positive impacts from wind power expansion on the scale and pace described in this chapter that are not likely to be realized in a business-as-usual future. Achieving the 20% Wind Scenario would involve a major national commitment to clean, domestic energy sources with minimal emissions of GHGs and other environmental pollutants.



# R EFERENCES AND 

# O THER 

# S UGGESTED 

# R EADING

AEP 2007. Interstate Transmission Vision for Wind Integration. American Electric

Power Transmission. http://www.aep.com/about/i765project/technicalpapers.asp

. AWEA 2007. American Wind Energy Association Web site, Oct.1, 2007: http://www.awea.org/faq/cost.html

. AWEA 2008. 2007 Market Report. January 2008 http://www.awea.org/projects/pdf/Market_Report_Jan08.pdf

. Black & Veatch 2007. Twenty Percent Wind Energy Penetration in the United State: A Technical Analysis of the Energy Resource . Walnut Creek, CA.

BTM Consult. 2007. International Wind Energy Development, World Market Update 2006. Ringkøbing, Denmark: BTM.

Denholm, P., and W. Short. 2006. Documentation of WinDS Base Case. Version AEO 2006 (1). Golden, CO: National Renewable Energy Laboratory (NREL). http://www.nrel.gov/analysis/winds/pdfs/winds_data.pdf

. Edmonds, J.A., M.A. Wise, J.J. Dooley, S.H. Kim, S.J. Smith, P.J. Runci, L.E. Clarke, E.L. Malone, and G.M. Stokes. 2007. Global Energy Technology Strategy: Addressing Climate Change . Richland, WA: Global Energy Strategy Technology Project. http://www.pnl.gov/gtsp/docs/gtsp_2007_final.pdf

EIA (Energy Information Administration). 2005. Electric Power Annual

. Washington, DC: EIA. Table 2.6. http://www.eia.doe.gov/cneaf/electricity/epa/epat2p6.html

.

EIA. 2007. Annual Energy Outlook . Washington, DC: EIA. http://www.eia.doe.gov/oiaf/aeo/index.html

. IPCC (Intergovernmental Panel on Climate Change). 2007. Climate Change 2007: Impacts, Adaptation and Vulnerability: Working Group II Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate change. PCC Report presented at 8th session of Working Group II of the IPCC, April 2007, Brussels, Belgium. http://www.ipcc.ch/ipccreports/ar4- wg2.htm**20% Wind Energy by 2030: Executive Summary** 21 Johnston, L., E. Hausman, A. Sommer, B. Biewald, T. Woolf, D. Schlissel, A. Roschelle, and D. White. 2006. Climate Change and Power: Carbon Dioxide Emissions Costs and Electricity Resource Planning . Cambridge, MA: Synapse Energy Economics, Inc.

RGGI (Regional Greenhouse Gas Initiative). 2006. “About RGGI.” http://www.rggi.org/about.htm

. Socolow, R.H., and S.W. Pacala. 2006. “A Plan to Keep Carbon in Check,” Scientific American , September.

Teske, S., A. Zervos, and O. Schafer. 2007. Energy [R]evolution: A Blueprint for Solving Global Warming , USA National Energy Scenario. Amsterdam: Greenpeace International. http://www.greenpeace.org/raw/content/usa/presscenter/reports4/energy-r-evolution-introduc.pdf

USCAP (U.S. Climate Action Partnership). 2007. A Call for Action. http://www.uscap.org/USCAPCallForAction.pdf

USGS (U.S. Geological Survey). 2005. Estimated Use of Water in the United States

in 2000. http://pubs.usgs.gov/circ/2004/circ1268/htdocs/figure01.html

WGA (Western Governors’ Association). 2006. Water Needs and Strategies for a
Sustainable Future, p. 4. http://www.westgov.org/wga/publicat/Water06.pdf

Wiser, R. and M. Bolinger. 2007. Annual Report on U.S. Wind Power Installation, Cost, and Performance Trends: 2006. DOE/GO - 102007-2433. Golden,

CO: NREL. http://www.osti.gov/bridge/product.biblio.jsp?query_id=0&page=0&osti_id

=908214

Wiser, R., M. Bolinger, and M. St. Clair. 2005. Easing the Natural Gas Crisis: Reducing Natural Gas Prices through Increased Deployment of Renewable Energy and Energy Efficiency . Berkeley, CA: Berkeley Lab. Report No.

LBNL-56756. http://eetd.lbl.gov/EA/EMP/reports/56756.pdf

Wood Mackenzie. 2007. Impact of a Federal Renewable Portfolio Standard

. Edinburgh, Scotland: Wood Mackenzie.22 **20% Wind Energy by 2030: Executive Summary** 

# L EAD 

# A UTHORS



# , R EVIEWERS AND 

# O THER 

# C ONTRIBUTORS

The U.S. Department of Energy would like to acknowledge the authors and reviewers listed below. Their contributions and support were important throughout the development of this report. The final version of this document was prepared by the U.S. Department of Energy. Overall report reviewers included the U.S. Department of Energy, National Renewable Energy Laboratory, American Wind Energy Association, and other selected National Laboratory staff.

Report Lead Editors and Coordinators Steve Lindenberg, U.S. Department of Energy, Brian Smith and Kathy O’Dell, National Renewable Energy Laboratory, Ed DeMeo, Renewable Energy Consulting

Services * and Bonnie Ram, Energetics Incorporated *

Lead chapter authors and technical advisors are listed below. A full list of contributors can be found in Appendix D of the complete report. Brent Alderfer, Community Energy Jeff Anthony, American Wind Energy Association Corneliu Barbu, GE Energy (formerly) Lori Bird, National Renewable Energy Laboratory Sandy Butterfield, National Renewable Energy Laboratory Lisa Daniels, Windustry Paget Donnelly, Energetics Incorporated Larry Flowers, National Renewable Energy Laboratory Trudy Forsyth, National Renewable Energy Laboratory Robert Gough, Intertribal Council on Utility Policy Robert Gramlich, American Wind Energy Association Jim Greene, National Renewable Energy Laboratory Maureen Hand, National Renewable Energy Laboratory Laurie Jodziewicz, American Wind Energy Association Ronald L. Lehr, American Wind Energy Association Walter Musial, National Renewable Energy Laboratory David Olsen, Center for Energy Efficiency and Renewable Technologies Kevin Rackstraw, Clipper Windpower Bonnie Ram, Energetics Incorporated Roby Robichaud, U.S. Department of Energy Michael Robinson, National Renewable Energy Laboratory Elizabeth Salerno, American Wind Energy Association Alison Silverstein, Consultant Susan Sloan, American Wind Energy Association J. Charles Smith, Utility Wind Integration Group Robert Thresher, National Renewable Energy Laboratory Paul Veers, Sandia National Laboratories James Walker, enXco Wayne Walker, Horizon Wind Energy Lawrence Willey, GE Energy Tom Wind, Wind Utility Consulting

* Support provided under subcontract to the National Renewable Energy Laboratory.**20% Wind Energy by 2030: Executive Summary** 23 Lead Authors for the Technical Appendices and Supporting Analysis for the

WinDS and JEDI Models include:

Nate Blair, National Renewable Energy Laboratory Mark Bolinger, Lawrence Berkeley National Laboratory Dennis Elliott, National Renewable Energy Laboratory Ray George, National Renewable Energy Laboratory Marshall Goldberg, MRG Associates Maureen Hand, National Renewable Energy Laboratory Donna Heimiller, National Renewable Energy Laboratory Tracy Hern, Western Resource Advocates Bart Miller, Western Resource Advocates Ric O’Connell, Black & Veatch Marc Schwartz, National Renewable Energy Laboratory Suzanne Tegen, National Renewable Energy Laboratory Ryan Wiser, Lawrence Berkeley National Laboratory

Members of the following advisory group supplied strategic guidance:

Rashid Abdul Mitsubishi Power Systems

Stan Calvert U.S. Department of Energy Edgar DeMeo * Renewable Energy Consulting Services, Inc.

Robert Gates Clipper Windpower Robert Gramlich American Wind Energy Association Thomas O. Gray American Wind Energy Association Steven Lindenberg U.S. Department of Energy James Lyons GE Global Research

Brian McNiff McNiff Light Industries Bentham Paulos Energy Foundation

Bonnie Ram * Energetics Incorporated

Janet Sawin Worldwatch Institute

Brian Smith National Renewable Energy Laboratory J. Charles Smith Utility Wind Integration Group Randall Swisher American Wind Energy Association Robert Thresher National Renewable Energy Laboratory

James Walker enXco

* Support provided under subcontract to the National Renewable Energy Laboratory.