Solar-power cells, also known as photovoltaics (PV), are semiconductors that convert sunlight directly to direct current (DC) electric power. “The sun’s light dislodges free electrons in each cell on the solar panel and collects them on conductors to create a volt. Each cell will produce a half volt of potential energy,” said Peter Lowenthal, executive director of the Solar Energy Research and Education Foundation (SEREF), Bethesda, Md.

A typical PV system consists of modules or panels made up of many cells, an inverter to convert the DC power produced within the cell to alternating current (AC) electricity, and other devices such as regulators and diodes to control current.

“PV systems can either be tied into the electrical grid, or operate independently,” said Peter Sheehan, executive director of the North American Board of Certified Energy Practitioners (NABCEP), Malta, N.Y.

In 2005, annual production rates of solar panels exceeded 1,700 megawatts (MW), according to Lowenthal. In other words, enough solar panels were made in 2005 to produce 1,700 MW of electricity.

Measured in the amount of watts available for use through photovoltaic (PV) installations, the market has grown from 430 MW in 2002 to 1,600 MW in 2005, according to Tom Dyer, vice president of marketing and government affairs for Kyocera Solar Inc., Scottsdale, Ariz.

“Global solar PV market growth has averaged a stunning 25 percent-plus annually over the last 10 years, with worldwide growth rates well over 35 percent over the last five years,” said Dan Shugar, president of PowerLight Corp., Berkeley, Calif.

In addition, PV technologies have declined in price every year since they were first introduced onto the market, thanks not only to improved research and development, but to steady increases in sales volume and increased manufacturing capabilities.

“According to the PV Roadmap from the U.S. Department of Energy (DOE), the average cost of electricity supplied by photovoltaics is projected to drop from 10.4 cents per kilowatt hour in 2004 to 5.7 cent per kilowatt hour in 2015, and then to 3.7 cents per kilowatt hour by 2050,” said Sheehan.

What’s driving the growth?

What has been termed an exploding market is being driven by increased demand, particularly in Germany, Japan, California and New Jersey.

“These governments and municipalities have the strongest incentives in place to encourage the use of solar power,” said Lowenthal.

For example, almost 40 percent of the costs of a solar-power system are paid for by the state in New Jersey. This has led to more than 200 new companies in the state promoting PV system installation in the last three years alone.

“For every dollar the state spends, it is getting even more from consumers, most of whom are motivated both by the desire to treat the environment better and by the long-term payback of using solar power to generate electricity,” said Lowenthal.

According to Dyer, widespread concern over the costs of conventional power is also driving the PV market growth, along with security concerns.

“People are looking for ways to offset the cost of energy by generating their own power and to become less dependent on centralized energy transmission facilities and sources of imported energy,” he said.

The most rapidly growing segment of the solar industry is for grid-connected systems, such as rooftop solar panels on homes or businesses that remain connected to the conventional electrical grid, according to Shugar.

“Even without incentives in some cases, as where electricity is more expensive during the middle of the day, or when solar power is used to support power-critical applications in banking or manufacturing, the economics are very compelling,” said Shugar.

PV systems can be used anywhere there is a need for electricity, including homes, offices, road signs and for telecommunication towers, for example.

“Any area that has high utility rates, unreliable electrical transmission from the grid, a lot of sunlight, or that has incentives from the state or utility benefits from PV systems,” said Thomas Glavinich, associate professor of Civil, Environmental and Architectural Engineering at the University of Kansas, and frequent contributor to Electrical Contractor.

Opportunities for contractors

Opportunities abound for electrical contractors to install solar systems, according to Glavinich.

“More than the installation of the panels themselves, the big opportunity for electrical contractors is more or less the installation of the balance of the system, including the solar equipment, power converters and inverters, batteries, wiring, conduit, and interfacing the solar power with the rest of the building’s systems,” he said.

Joe Benga, vice president of projects at PowerLight goes even further, calling the opportunities for electrical contractors in the solar market practically endless. He bases that on the phenomenal 25 percent market growth rates, with 927 MW installed worldwide in 2004 alone—84 MW of which were installed in the United States.

“Between California, New Jersey, and other states that are beginning to see the advantages of solar power and that are offering incentives, the opportunities to install, design and to become a single-source integrator of solar power with large commercial grid-connected and residential systems could be endless,” he said.

Contractors, however, need to keep in mind that these opportunities are segmented and do not just include installing solar power systems for general use buildings. There is also the remote mountaintop segment. According to Lowenthal, this is a stable market that generally is focused on the telecommunications industry, the residential sector, and the commercial construction sector (which usually involves larger, 100 kilowatt and above arrays), and the government sector, which will be a growing opportunity as government agencies mandate the use of more renewable energy sources for their facilities.

“It will be important for contractors to become solar- credentialed as PV involves issues not prevalent in traditional electrical construction,” he said.

There are several of those issues that electrical contractors must address if they are to be successful in the growing market.

“Contractors need to either gain or have experience with PV technology, direct current wiring, and specific power conditioning equipment, such as inverters, that PV systems require,” said Lowenthal.

Contractors also need to understand the technology and how the various components tie together so they can work with owners to decide the best type of PV system that will fulfill their needs and meet power-generation expectations.

“Such knowledge can be obtained from manufacturers, and certification for PV installation can be obtained from groups such as NABCEP,” Glavinich said.

In addition, contractors will need to understand the unique nature of PV installations to take advantage of the opportunities, such as orienting the panels properly to the sun’s position and movement, avoiding shading, and learning how to integrate the solar panels with the building’s traditional electrical system so that the system operates to its fullest potential.

“It’s a new discipline for electrical contractors and, although not particularly difficult, attention must be paid to these types of details,” Dyer said.

It is predicted that PV systems will be deployed in more applications and become part of everyday life for many consumers.

“In the same way that electronic devices such as cell phones are everywhere today, we believe that solar technologies will become as pervasive in the next decade,” said Sheehan.

According to Shugar, PV usage in homes and businesses will continue to increase rapidly in the coming years, including the increased usage of new commercial systems of 500,000 watts or more, as well as small, standardized systems for rooftops and attractive building-integrated devices for commercial buildings.

“Increased sales volume and economies of scale will continue to drive the market, and attempts to bring electricity to the developing world will frequently employ solar as the lowest-cost alternative,” he said.

New markets will also open up to PV where government incentives are prevalent.

“For example, over the next two years, as part of the Energy Policy Act of 2005, commercial building owners will be able to write off 30 percent of the cost of a new PV system. Residential incentives under the act are capped at $2,000,” said Lowenthal.

Contractors also need to keep an eye on new trends such as the integration of PV materials with traditional building products such as glass and roofing materials.

“PV panels are no longer being installed just on roofs or nearby, but [are] becoming a part of the building skin,” said Glavinich.

Advances in PV technology, improved building aesthetics, increasing energy costs, and greater environmental awareness are leading to an emerging PV market that will provide the educated electrical contractor with a shimmering array of opportunity.    EC

BREMER, a freelance writer based in Solomons, Md., contributes frequently to ELECTRICAL CONTRACTOR. She can be reached at 410.394.6966 or darbremer@comcast.net.