Blowin' in the Wind

Blowin' in the Wind

May 05 - Power Engineering

In addition to providing Colorado residents with a clean source of electricity, the Colorado Green Wind Project is providing much needed revenue to local ranchers, business owners and government.

Dedicated in May 2004, the 162 MW Colorado Green Wind Projects 108 wind turbines are producing more than renewable electricity on the rural plains of southeastern Colorado. Located in Prowers County, near the City of Lamar (population 8,800), Colorado Green is expected to provide enough power for approximately 52,000 average American households, according to figures provided by the American Wind Energy Association (AWEA). Local ranchers, business owners and local government, however, are also touting the project's economic benefits as new key developments for the area.

"Lamar's new wind project is already bringing significant new economic development opportunities, including a new source of income to local farmers and increased tourism opportunities," said Lamar's Mayor Elwood Gillis. 'The pioneers began harnessing wind 150 years ago to pump water for their livestock and homes. Wind is even more important for our city and region today. It is vital that our nation develop renewable energy sources, such as wind, to their fullest extent to overcome our reliance on fossil fuel and provide local energy security."

Comprising 108 GE 1.5 MW units, the largest wind turbines assembled in the United States, each machine features three 113- foot blades joined by a rotor - the diameter of which is wider than the wingspan of a jumbo jet.

PPM Energy and Shell WindEnergy acquired the project from GE Energy through a joint venture agreement in October 2003 (Shell WindEnergy owns a total of 393 MW of wind energy resources while PPM Energy owns or controls more than 830 MW). The power, purchased by Public Service Company of Colorado (PSCo), a part of Xcel Energy, was solicited through a competitive bidding process, which included several other forms of electricity generation. Xcel Energy currently purchases the output from 829 MW of wind power in the United States.

"The Colorado Green development was borne through a competitive bidding process where it competed against other forms of electricity generation including natural gas and coalfired generation," said Terry Hudgens, PPM's CEO. "That Colorado Green was found to be one of the lowest cost alternatives shows what we've said all along - today's wind power is cost-competitive with any other form of new generation."

Lamar, CoIo., Mayor Elwood Gillis stands near several of the GE Energy wind turbines that comprise the Colorado Green Wind Farm.

GRID CONNECTIVITY

Because Colorado Green is in a rural part of the state, connecting it to the grid required a considerable upgrade to the local transmission infrastructure. The backbone of the electrical system now consists of 20 miles of underground cable within the wind farm. Power comes from the turbines at 590 V, is converted to 34 kV and then stepped up to 230 kV at a new Xcel Energy substation. More than 50 miles of direct buried cable was laid from the turbines to the substation, followed by 44 miles of 230 kV transmission lines.

In addition, 25 miles of road was built for the wind farm. The 108 wind turbine concrete foundations each consumed 300 yards of concrete and 45,000 pounds of rebar. At the height of construction, subcontractors employed nearly 400 workers at the site.

"Because of the drought, the economy has been really bad, and the wind farm has been a real blessing," said Linda Mulberry of Workforce Colorado, the state job service agency.

Craig Cox of the Western Business Coalition for New Energy Technologies conducted a study of project impact on behalf of the U.S. Department of Energy. According to his figures, the total site services required for construction of a typical 100 MW wind farm is about 419,020 man hours - equivalent to about 53,377 days of work at the site (Table 1).

TABLE 1

SITE SERVICES FOR A TYPICAL 100 MW WIND FARM

With construction completed, Colorado Green continues to provide 15 to 20 full time permanent jobs to the community, according to Cox. Local property owners also benefit from royalties based on the power generated. Typical payments range from $3,000 to $6,000 annually per wind turbine.

The Emick Ranch, near Lamar, for example, is home to 98 GE 1.5 MW turbines. They reside on about 10,000 acres of the Emick family's working cattle ranch. "With the arrival of the wind on our ranch, we no longer have to rely solely on cattle to pay our way," said Don Emick. "The turbines are beautiful to look at and the cattle sit under them for shade. The turbines and access roads take up a minimal amount of land and now pay us an annual royalty."

The local community is also gaining through tax dollars, employment opportunities and tourism. It is estimated that Prowers County will make an additional $2 million annually in tax revenue from the project with an overall 29 percent increase in the county tax base. Figure 1 illustrates the growth in only one month's sales tax revenues. County Assessor Andy Wyatt has these additional funds earmarked for several worthy recipients, including $189,000 annually to the Prowers Medical Center, $203,000 to the school district bond fund and $917,000 for the school district general fund.

MORE TO COME

While Colorado Green may be the first large wind farm in the state, it probably won't be the last. Based on the current price of gas, Xcel Energy testified to the Federal Energy Regulatory Commission (FERC) that the wind energy supplied by Colorado Green will save its ratepayers $4.6 million.

Not surprisingly, there is strong support throughout the state to add more wind resources to the grid. In November 2004, Colorado joined 17 other states requiring utilities to provide a percentage of their retail electricity sales from renewable resources. This is known as a renewable portfolio standard (RPS). Although Colorado is the 17th state to pass a RPS, it is unique because its RPS was put in place by a ballot initiative. The standard is scheduled to take effect in January 2007, when 3 percent of energy consumed will be from renewable sources. (Currently only 2 percent of Colorado's electricity comes from renewable sources). The state's utilities will be required to produce 6 percent of their energy from renewable sources between 2011 and 2014 and 10 percent by 2015 and afterwards.

FIGURE 1

PROWERS COUNTY SALES TAX COLLECTION COMPARISON

Although the applicable renewable technologies include energy derived from wind, solar, geothermal heat, biomass, landfill methane, animal waste, hydrogen fuel cells and small-scale hydroelectric, wind is expected to be a large part of the renewable mix.

"Republicans and Democrats are working together to provide real life solutions for Colorado," said House Speaker Lola Spradley (R- Beulah). "We want to provide Colorado with more energy choices, as well as numerous jobs that help rural Colorado."

The GE 1.5 MW unit, pictured here, is the largest wind turbine assembled in the United States. It features three 113-foot blades joined by a rotor.

BY DREW ROBB, ROBB EDITORIAL

Author

Drew Robb, a freelance writer based in Southern California, writes about engineering and technology.