The Evolution of Wind Energy in the Tehachapis

Editors Note: Commercial wind generation has evolved rapidly in the last 30 years.  In this excellent article by Nikki Cummings you can learn how a major wind resource area, the Tehachapi mountains in California, has evolved and improved across four generations of wind technology.

It’s been 30 years since the first wind turbines were installed in the Tehachapi-Mojave Wind Resource Area. It is considered one of the premier places in the nation for wind power and one of the windiest places in the world. Repowering and new development will continue to flourish in this renewable-rich area thanks to the first-of-its-kind transmission line and a 20-year contract with Southern California Edison. It represents the largest wind energy contract ever signed by a United States utility. A look back at the Tehachapi area reveals that some of the same challenges the wind industry faced then are the same challenges we’re facing today—regulatory hurdles, environmental concerns, costs, and negotiating with the utilities.

A number of wind farms call Tehachapi home—including Terra-Gen Power, enXco, NextEra, Cal Wind Resources, Coram, Oak Creek Energy Systems, GE Energy, AES, Mogul Energy and Windland. This isn’t surprising considering that the winds through the pass average 14 to 20 miles per hour from one year to the next. Wind speeds vary with the terrain, season, and time of day. Average wind speeds approach nearly 9 meters per second (about 20 miles per hour). This places much of the Tehachapi Pass in wind power class 6 (these classes range from class 1, the lowest, to class 7, the highest).

The first turbines erected in Tehachapi were about 45 to 60 feet in height and they produced about 25 to 60 kilowatts. Today, they stand about 400 to 500 feet and they produce about 1 to 2.4 megawatts. The area is enjoying a new breath of life thanks to the new transmission line and a 20-year contract with Southern California Edison and Terra-Gen Power for the Alta Wind Energy Center, 1,550 megawatts (MW) of wind energy development. It represents the largest wind energy contract ever signed by a United States utility and it also means that wind developers have better access to the California grid and the ability to sell to multiple utilities.

It also represents a major hurdle since a group of visionaries installed the first machines in the early 1980s. Multiple generations of wind turbine technology are still up and running in Tehachapi. There are the single- and double-blade turbines that generate between 25 to 60 kilowatts to the more modern three-blade turbines that generate up to 4 megawatts. It’s four generations of turbines with an installed capacity of about 785 megawatts.

A lot has happened since the first machines were installed. After overcoming numerous regulatory hurdles, SCE officially began the construction of its Tehachapi Renewable Transmission Project (TRTP). The first phase of the TRTP cost $1.8 billion and will ultimately result in a, high-voltage transmission system capable of delivering 4,500 MW of clean energy into the Los Angeles metropolitan area which is located about 100 miles south of Tehachapi. Executed power purchase agreements to date will allow up to1,500 megawatts or more of power generated from new projects to be built in the Tehachapi area. It represents the first construction of a “public” transmission line that carries electricity generated at the park straight to the grid. This state initiative to upgrade the transmission out of Tehachapi began in 2008 and is expected to be completed by 2012. It has proved to be a catalyst for multiple projects including Coram Ridge, consisting of 34 Vestas V90s, developed by Coram Energy Group & Brookfield Renewable Power; Windstar, consisting of 4 Gamesa G52s, 37 G80s, and 16 G87s, developed by Western Wind Energy; and Alta I-V, consisting of 100 GE 1.5s and 190 Vestas V90s, developed by Terra-Gen Power. The Windstar project, whose general contractor is RMT, will bring the first Gamesa turbines to the region. These projects are all slated to see construction begin in 2010.

According to SCE, the TRTP will allow them to more than double its wind energy portfolio and envisions connection of more than 50 square miles of wind projects in the region, which is triple the size of any existing U.S. wind farm area. Officials estimate that it will eventually provide 4,500 megawatts of electricity, which could make it the largest wind project in the nation. The new wind farms are expected to eventually comprise 1,750 to 2,000 turbines. Not only does this triple the size of any existing U.S. wind project, but it is also expected to out perform the world's current largest wind farm. Phase 1 of the TRTP, which includes segments 1 through 3, out of 11 planned segment improvements, is expected to be completed in 2010.

Randy Hoyle, Vice President and Head of Wind Development for Terra-Gen Power, LLC, had this to say. "Terra-Gen Power is excited to be the first renewable energy company to utilize Southern California Edison's (SCE) newly constructed Tehachapi Renewable Transmission Project. The 720 MW first phase of the project will increase California's installed wind capacity by nearly 25 percent and contribute substantially to the state's renewable energy needs.”

The transmission line has definitely strengthened the industry here. “According to the Kern County assessor’s office, by the year 2030 the wind industry will have assessments equal to that of the oil industry in Kern County. This is a big deal. We never imagined when we started that we would rival the oil industry,” says Linda Parker, executive director of the Kern Wind Energy Association.

The approval of the TRTP is a notable exception to difficulties with long-distance transmission in America. In fact, it's the first major transmission project in California being built specifically to access renewable generators in a remote, wind-rich resource area. “Prior to that system coming, we weren’t growing and we weren’t going to. We couldn’t take one more watt,” says Parker. “The construction of the transmission line is a major accomplishment that many people have worked tirelessly on. It gives the wind industry options and the ability to contract with other electric utility companies.”

Numerous entities, companies and individuals played a major role in the conception, planning, development, and approval process for the transmission project, which has involved a number of precedent-setting decisions, both regulatory and in the courts. It is showing the way and sets an example for other badly needed transmission infrastructure projects in this country. Hal Romanowitz, President and COO, Oak Creek Energy Systems was one of these key players. He said it is important that transmission expansion facilities be well planned and scaled to serve the large regional needs if they are to succeed.

“TRTP progressed from our local development and planning efforts into the state-wide planning, and on top of that it took five studies to get the right focus onto a solution that was good for the entire state, not just a limited group, and the TRTP that is being constructed is very good for serving a substantial range of clean energy projects and to the overall grid reliability as well. TRTP Planning in California was the start of a superior process for regional planning that continues and which will ultimately do well for the electric needs of the state on a proper scale,” said Romanowitz.

He continued, “Getting the transmission expansion scaled to the proper level, and getting the costs rolled into rates paid by users of the system is extremely critical. This is one of the biggest problems blocking transmission expansion success across the country. To be proper, such user funded expansion needs to be part of a regional transmission planning process, so that the expansion is properly scaled, and will best serve broad needs. One issue is that in some states, users are strongly objecting to pay for transmission used to transport new renewable energy across their state to others in remote locations. However, a strong national transmission grid is critical for our country, and we are not getting what we need with so much provincialism.”

Now that transmission has moved beyond provincialism in Tehachapi, what does the future hold for this wind-rich region? Repowering and new development are sure bets, said Ed Duggan, executive vice president, Oak Creek Energy.  

“Oak Creek is an example of a wind project that is repowering and producing more energy as a result. This repowering of smaller turbines with bigger, more efficient turbines has been going on for over 10 years now and it will continue at Oak Creek and on other older existing wind farms until most of the early (1980’s) generation of turbines, which are now approaching 30 years in age, have been replaced. The potential upside of newer, bigger, better turbines is too great to ignore. As far as new development goes, we’ll see a lot more on the Mojave side of the Tehachapi Pass and a little more on the Tehachapi side, but much of the new capacity will also be in the nearby Antelope Valley area,” said Duggan. “This region will grow to about 4,500-5,000 megawatts of total capacity in the next 5-10 years; it’s going to happen quickly. After that, we’ll continue to expand at a slower rate and by the year 2040, we should be somewhere around 10,000 megawatts of total capacity.”

With numbers like these, we have reason to hope that the next 30 years will treat this renewable-rich area just as well.

AUTHOR BIO: Nikki Cummings is the co-owner and president of World Wind Services and a Tehachapi native. She is currently serving as president on the Board of Directors for The Wind Energy Center, and Board Member of the San Diego Chapter to Women of Wind Energy. She was also one of the nominees for the 2009 Rising Star Award for the Women of Wind Energy Association.