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Texas Solar Power Shines Strong

While Texas has been hit by the decline in oil prices, the state has also recently been home to some large-scale solar power developments, including the 118-MW Alamo 5 project built by ConEdison Development and Mortenson Construction to supply CPS Energy.

By Paul MacDonald

It seems that as the bottom fell out of the market for oil, solar power is taking off in the state of Texas.

In recent years, the price of oil has fallen off a cliff—it hit a peak of $140 a barrel in 2008, but more recently has been trading around $50, after being as low as $26 a barrel early in 2016.

At the same time, there has also been growing interest in and development of solar power in the Lone Star state—bringing with it millions of dollars of investment and hundreds of jobs.

The city of San Antonio is now in seventh place among major U.S. cities for installed solar capacity, with 141 MW of solar power as of the end of 2015. The city's municipally-owned utility, CPS Energy, has been supporting solar power in a major way.

Among the most recently completed solar projects in Texas is Alamo 5, a 118-MW (DC)/ 95-MW (AC) system that features one of the world's largest dual-axis tracker systems, featuring trackers from Sun Action, and a total of almost 380,000 solar modules from three companies: Mission Solar, JinkoSolar, and Trina Solar. The dual-axis trackers, with their patented solar sensing technology, move the panels horizontally and vertically to follow the sun across the sky and optimize power on the site.

Built to supply San Antonio-based CPS Energy, the project was developed by CPS Energy partner OCI Solar Power and purchased by ConEdison Development (CED) in early 2015. The project site, located 85 miles west of San Antonio, is 990 acres—about the size of 756 football fields.

This is one of five Alamo solar facilities presently serving CPS Energy. ConEdison Development—which now ranks as the fifth-largest owner of renewable power infrastructure assets in the U.S.—has played a development, ownership, and operating role in three of the completed projects. San Antonio-based OCI Solar Power is the contracted developer of a total of 10 projects, delivering 450 MW overall to CPS Energy. All of the installations will be complete by the end of 2016.

CED's experience on the nearby Alamo 3 and 4 projects helped with its approach to building the Alamo 5 project with construction partner Mortenson Construction, said ConEdison Development's construction manager, Dennis Brennan.

The technology for the trackers on the Alamo 4 project was different, but they used similar technology on the Alamo 3 project. Both projects gave the company a good lay of the land, so to speak, in building solar in southwest Texas.

"The Alamo 3 project was a very different scale—at 7 MW (DC)/6 MW(AC)—but we certainly gained a lot of knowledge on how to assemble each tracker," said Brennan.

The Alamo 3 project has 510 trackers, and Alamo 5 has 9,000 trackers.

"There was definitely some knowledge gained from the other projects," added Brennan. "Although the scale was quite different, assembling the trackers is a repetitive task. So you figure out the best practices—the best way to safely and effectively install the trackers."

Mortenson was also the EPC on the Alamo 3 project.

"On a project as big as Alamo 5, it's imperative that we select the right EPC contractor to build the project—we need to know they have the knowledge, people, and experience to successfully take on and complete the project."


Mortenson, Brennan noted, has extensive experience in solar power project construction.

The start of a project sees CED and its construction and design partners strategizing about the best approach to a project and the logistics of having hundreds of workers—and trucks—on the site. "People are our most important asset," Brennan explains. "When you have up to 500 workers on site, you want to have the plan and knowledge on how you are going to best utilize those people."

With Alamo 5, the project was about 15 percent started when CED acquired it, so some things were already in place.

"With the CED team and the Mortenson team, we were able to collectively come up with the best plan and the most effective way to continue to carry out construction."

CPS Energy was also an instrumental part of the process, Brennan added. "They've been good to work with and offered us a lot of assistance, from the front end right through to when we were going online. There are a lot of requirements that have to be met, and they worked hand in hand with us to get the project completed, and to get power out to the grid."

Brennan noted that with huge projects such as Alamo 5, they tackle it on a big scale but also on a modest scale.

"You can't get overwhelmed by the scale of the project—you need to have a methodical approach," he explained. "With a project like this, you break the big project up into a series of smaller projects. So Alamo 5 was broken down into 59 identical blocks, each of them two MWs in size. Each block is identical, so that makes it more manageable."

Before any construction started, the site had to be cleared and grubbed—there was a lot of mesquite. The cleared mesquite was sold as biomass to a nearby concrete plant to generate energy, which means even the clearing of the site resulted in power being generated.

"It really was a win-win that way, for us and for the concrete plant," said Brennan. "The mesquite burns at a very high BTU, so it makes for a very useful energy fuel."

Renewable energy project construction sites, whether solar or wind power, often have road and traffic challenges—especially large projects. But Brennan noted that CED worked very closely with the nearby communities of Uvalde and Knippa on the flow of truck traffic.

"We had a very systematic approach to the trucking," he says. "Mortenson would bring in about 40 trucks a day to the site, with materials such as the tracking equipment and solar panels. It was very well orchestrated. We worked together so that it was a seamless and successful operation, and that there were no issues or concerns that would affect the nearby communities."

As with much of Texas, the region has been impacted by the drop in oil prices, and the project was welcomed for its economic contribution, which included workers filling up local motels and restaurants. "Regardless of the project, we try to make the impact we have as positive as we can for the local communities," says Brennan.

 With the dual-axis trackers (above), ConEdison Development found that the Alamo 5 project comes up to peak production very quickly in the morning, and they are able to maintain that flat line production all day long, almost until sunset. So instead of having a bell curve for power production, such as with single-axis trackers, it's more straight up in the morning, steady through the day, with a drop off later in the day.

It may be an understatement, but weather can be an issue with construction projects in Texas. Case in point: large areas of Texas were hit with heavy rainfall in April of this year, causing extensive damage and delays in major projects.

Even though the Alamo5 project was completed by the end of 2015, it still saw its share of weather challenges.

"In the first week after we acquired Alamo 5, the region had one of the biggest rainfalls in its history—we had about a six-inch rainfall," said Brennan.

Fortunately, it happened early in the construction process and there was no damage.

"We were able to mitigate any loss of construction days, by working closely with the contractor," Brennan explained. "We were able to find the best way to work around the muddy conditions that were created by the heavy rain. Later, when it came to having high temperatures on the construction site, we made sure all the workers were very hydrated, that they had bottles of water, and people were going around the site with water and coolers."

As part of its safety approach, Mortenson had its hundreds of workers on site limber up each morning with calisthenics-like stretching and bending exercises.

"Really, it comes down to management, management, management to keeping the project moving forward and making sure people are safe," said Brennan. "I think our CED people, working with Mortenson, did a very good job of that—we had a very strong team."

The Alamo projects were the first time CED, which has developed and built a large number of solar projects, used dual-axis trackers.

"We have a lot of projects throughout the country, with single-axis trackers and fixed tilt," says Brennan. "Dual-axis trackers were new to us, but we welcomed them with open arms, and operationally, they work well."

Each tracker moves on either a north-south or east-west axis, he explained.

"Each axis has a brain, or solar sensor, mounted right on the panel, and it moves the panel to capture the sun at an optimal angle all day long—the sensors look at the sun and move the tracker and panel, until it gets the best angle. As the sun moves through the day, the sensor will tell the tracker motor to move the panel to get the maximum irradiance."

Essentially, he says, there is constant communication between the solar sensors and the tracker controller—they are working every minute of the day to evenly optimize production.

 The Alamo 5 project site, located 85 miles west of San Antonio, is 990 acres-about the size of 756 football fields. As its number implies, it is one of five Alamo solar facilities presently serving CPS Energy. ConEdison Development has played a development, ownership, and operating role in three of the completed projects.

"What we've found with the dual-axis trackers is that we come up to peak production very quickly in the morning, and we are able to maintain that flat line production all day long, almost until sunset.

"So instead of having a bell curve for power production, such as you get with single-axis trackers, it's more straight up in the morning, steady through the day, with a drop off later in the afternoon. We get that even in the winter months, when the sun is lower in the sky."

The solar resource in Texas is nothing short of great, says Brennan. There is a bit of a downside because the temperatures get high, and there can be a drop in solar panel efficiency. "But the sunlight we get there is very strong. I'm from the northeast, and I noticed right away the intensity of the sun—it's a good part of the country for solar power."

Weather reports for the area indicate 200-plus days of good-to-excellent sun, with many of the remaining days still offering some sun.

Having worked on a number of solar projects, Brennan said one of the major ingredients to a successful project is safety.

"It's one of CED's core values," he explained. "We can't talk enough about safety with a project this size, the equipment on site, and the overall number of moving parts. We need to have a great safety program from our contractors, and that is supported by ConEdison Development.

"If you start with a good safety program, and you follow up with a good quality control program, that's a successful recipe for us."

He noted there was a great sense of accomplishment and pride within the CED/Mortenson team on the successful completion of the Alamo 5 project. And that extends further, now that the project is operational.

"You look at not only what we've accomplished as a team in building the project, and for green energy, but also what we've done for the local economy in a part of Texas that has been hit hard by the downturn in oil prices."

Some of the workers on the Alamo5 project were, in fact, former oilfield workers.

"Many of them have great experience that can be brought over to the solar side. And what people don't know, we can train. They are very hard workers, and they want to do a good job. They know the climate and are used to being out in the sun all day."

Alamo 5 helps fulfill the commitments of CPS Energy's ambitious New Energy Economy initiative. As of the start of this year, the initiative's impact included the creation of more than 950 jobs, $57 million in payroll, and an annual economic benefit of $1.6 billion. The New Energy Economy maximizes the local economic development benefits generated by strategic investments in clean energy and innovative technologies like solar power, LED lighting, and smart grid infrastructure, says CPS Energy.

As an example of progress made under the initiative, the following San Antonio-based New Energy Economy partners manufactured some of the major components for Alamo 5:

  • Mission Solar Energy, the first and only U.S. manufacturer of N-type solar cells and solar photovoltaic (PV) modules
  • Sun Action Trackers, dual-axis trackers
  • KACO inverters.

There is more solar power to come for the utility.

"We are the solar leader in Texas with 230 megawatts in the ground, and that will more than double to 500 megawatts by year's end," said Cris Eugster, CPS Energy's executive vice president and chief generation and strategy officer. "Alamo 5 represents a significant milestone in our commitment to generate at least 65 percent of our energy from low- or no-carbon resources by 2020."

As for CED, it has moved on to another major solar project-the Alamo 7 project in Haskell County northwest of Alamo 5. Later this year, Alamo 7 will add to the more than 950 MW (DC) / 750 MW (AC) of renewable power the company generates in California, Arizona, Nevada, Nebraska, New Jersey, Massachusetts, Pennsylvania, South Dakota, Rhode Island-and Texas, of course.