It was bright and sunny in the Los Angeles area, the kind of summer day the Chamber of Commerce likes to trumpet. Convertible tops were down on the freeways, tourists behind sunglasses were taking in the sights and residents accustomed to the warm, balmy weather were attired in cotton comfort. And on the roof of a large, low rise building in an industrial area, 2,610 photovoltaic (PV) panels basking in the same sunshine were pumping out a powerful stream of electricity.
The 2,610 solar panels are part of a jointly funded project by the Los Angeles chapter of the National Electrical Contractors Association (NECA) and the International Brotherhood of Electrical Workers (IBEW) Local Union 11 to supply power to their co-sponsored Electrical Training Institute of Southern California. The 457-kilowatt PV system, capable of producing 900,000 kilowatt-hours annually, is believed to be the 10th-largest privately owned system in the United States.
While PV systems currently generate only a small fraction of the power consumed in the United States, some experts believe that as the demand for electricity continues to grow, so will the need for PV power generation. The driving force behind the increasing interest in PV systems is the climbing costs of fossil fuels and the related rise in the cost of power, along with anticipated greater electricity demands to meet the needs of current and future technologies. But the real PV bonus is that the energy comes from a free, unlimited renewable resource.
The Electrical Training Institute (ETI) is taking advantage of that bonus now: ETI power costs have been dramatically reduced, a state rebate program and federal tax credit substantially slashed the overall cost of the $3 million project, and the system benefits the environment and, at the same time, provides a showcase to stimulate further PV projects and work of this type.
The NECA and IBEW-funded institute, located in the City of Commerce on the outskirts of Los Angeles, trains 1,500 apprentices annually. According to Executive Director Don Davis, the institute began considering the possibility of installing a PV system in 2003. However, he said it wasn’t until 2004, after careful analysis, that a decision was made to go ahead with the project for the 144,000-square-foot facility.
“Could our building withstand the structural elements of the system, what are the costs of the system, what are the projected paybacks of the system?’’ Davis said, in outlining some of the key questions that were looked at before approval was given.
Davis said that after many months of carefully studying the various facets of the proposed project, approval was given and Independence Power Inc., a Los Angeles company that specializes in solar power and power management, was selected as the system architect and general contractor by ETI. In turn, Independence Power selected NECA member, Electric Service & Supply Co., Pasadena, Calif., as the subcontractor for the installation of panels and connecting the system to the existing wiring in the building.
In addition, a structural engineer and union structural subcontractor were contracted for the custom design, fabrication and installation of panel support structures that had to be capable of withstanding both earthquakes and high winds.
“We think it’s one of the top [PV] systems supported by a steel structure in the world,” said Fred Cherrick, Independence Power president. “It’s within the top five in the world in terms of size that is supported by a steel superstructure.”
Because of the configuration of the building, the PV system actually is divided into two systems. One system has five rows of panels, each 221 feet long, while the other has three rows, each 255 feet in length. Construction began in May 2005 and was completed a year later.
“We could have done it with one system,” Davis said. “However, we thought that having two systems would be advantageous in the event we have to shutdown. Chances are, if anything goes wrong, we’ll only have half our system down at any one time, rather than bring all of it down to make a small repair.”
What comprises the ETI system, which not only serves the institute but also the adjoining offices of the union local and pension trust?
Power from the 2,610 multicrystaline silicon panels manufactured by Kyocera Solar Inc., Scottsdale, Ariz., flows into 13 Independence Power custom-designed combiner boxes on the roof. From there, the electricity from the 175-watt direct current (DC) panels in the dual systems goes into two inverters and then into two transformers, before reaching special Southern California Edison electric meters.
The utility’s meters spin either forward or backward, depending on whether energy is being drawn from the utility or excess power is being sent out onto the grid by ETI. The meters serve both as the termination point for the PV system and the connecting point for the existing ETI wiring.
According to Davis, the real brains of the automatically operated system lie in the two inverters. He explained that they have a certain amount of computer intelligence that allows them to monitor the DC power output to gain the maximum efficiency. The inverters, he continued, are “actually monitoring the panels and making adjustments on how the panels are operating on the roof.”
“We’re getting about 92 percent efficiency, where prior, about the best other systems were able to achieve was 88 percent,” Davis said.
He attributed part of this higher efficiency to a decision to replace factory-provided slip connectors with direct wirenut connections. To ensure the highest generating efficiency from the roof panels, Electric Service & Supply mounted them on the galvanized superstructure, which supports them at a 23-degree angle, the optimal sun exposure position determined for the location. Six panels are arranged in each individual array column and reach 10 feet in height.
Gary Leder, Electric Service & Supply vice president, said working with PV panels is different than ordinary electrical work. He specifically pointed out that extreme caution is used because the circuits are hot immediately upon exposure to the sun.
“As soon as you take a solar panel out of the box, that thing is alive and working,” Leder said. “So immediately, you have hot circuits that warrant precautions. When we were working on a group of panels, we had to cover them and then test them to make sure that the voltage had bled off and that there was no potential there for anyone to get hurt.”
Leder said it took five months to complete work on the company’s contract, which he said was just under $500,000. During the job, Electric Service & Supply installed approximately 12,000 feet of conduit and 50,000 feet of wire.
As part of the job, Leder said, his crew also installed wiring to a specially constructed control/display room, where one of the two inverters is housed, along with a computer workstation.
The workstation is for a computerized database system to capture power production and usage and display it visually on a wall-mounted screen. Independence Power designed the specialized software, which Cherrick calls a Power Almanac. Besides continuously monitoring the automatic PV system and the building’s power usage, the Power Almanac stores and can display current and past data.
“Our facility uses about 1.1 million kilowatt-hours per year,” Davis said, in discussing the cost savings the PV system provides. “We’re capable of producing about 900,000 kilowatt-hours per year. So we will be able to produce about 80 percent of our usage.”
The back-and-forth flow of power between ETI and Southern California Edison that provides this 80 percent savings revolves around the special meters in the two separate service drops to the institute. The month, day of the week, time of day and direction of the power flow are all factors taken into consideration and used in calculating pricing and ETI’s credit on its bill for the power it exports.
Edison has three price categories—on-peak, Monday–Friday, noon–6 p.m.; mid-peak, Monday–Friday, 8 a.m.–noon and 6–11 p.m.; off-peak, Saturday, Sunday and all other times—from the first Sunday in June to the first Sunday in October. The rest of the year, Edison eliminates on-peak, with mid-peak running from 8 a.m. to 11 p.m. Edison charges more for on-peak and mid-peak power, but it also credits ETI with the equivalent higher figure for electricity it sends to the grid during those peak periods.
“One of the best advantages of our particular system is being that we are an apprenticeship training facility, our training classes are weekdays between 5 and 8 p.m. and on an occasional Saturday,” Davis said. “So therefore, our major use of power is during mid-peak or off-peak hours and our major production of power is during the mid-day or high-peak hours when our power is worth more.”
Another major financial advantage of the system has been a rebate and tax credit. The California Public Utilities Commission has a program whereby a utility gives a subsidy for installing a PV system—each watt is worth a specific dollar figure. In addition, the federal government offers a 30 percent tax credit.
“So we paid a million and a half for a $3 million system,” Davis revealed, adding that it is expected that payback or the recovery of costs period will be four and a half years, less than initially forecast.
But there is yet another PV system payback that benefits the environment. To generate the amount of power produced annually by the rooftop panels would require 820,000 pounds of coal—equal to eight rail cars—or either 8.1 million cubic feet of natural gas or 99,000 gallons of fuel oil. By not burning these fossil fuels, ETI’s nonpolluting system will eliminate 1,540,000 pounds of carbon dioxide, 3,250 pounds of nitrous oxides and 1,638 pounds of sulfur dioxide annually.
These statistics and others, along with graphs and information about the advantages of ETI’s PV system, are displayed on a large video screen in its glass-enclosed control/display room. The dual-purpose room, containing the inverter, computer database workstation and a solar panel exhibit, was designed to serve as a showcase for the solar-powered system.
“This will be a good showcase for education,” said Jim Willson, executive director of the L.A. County NECA chapter. “We plan on bringing user groups in to show them how this [PV project] is done, how our contractors can do it and how it can be installed by quality labor.”
Davis, in citing still other advantages of ETI’s PV system, said, “There are no moving parts. The maintenance is extremely low. About the only thing that one needs to maintain is the inverter.” Plus, he pointed out, by using the building’s empty roof space, no additional land was required for the installation.
Looking at the bigger picture, the ETI executive director is convinced that solar is a viable solution to our energy problems.
“I see this as a limitless, renewable source of energy … and it’s free,” he said. “We’re not paying a dime for the sun that hits those panels.” EC
MAZUR is a freelance writer based in Los Angeles and can be contacted at firstname.lastname@example.org.