Integrating PV into Building Systems

The Integration of photovoltaics (PV) into building systems represents a growth market for the electrical contracting firm. PV combined into exterior building elements such as the building’s roof and exterior walls is typically referred to as building-

integrated photovoltaics (BIPV). With BIPV, the entire exterior of the building has the potential to be an electric power generator by harvesting incident sunlight and converting the captured solar energy into electricity. For example, today it is possible to get photovoltaics into a variety of building materials ranging from roofing shingles for residential and light commercial buildings to vision and spandrel glass panels for commercial and institutional buildings. As the PV market grows, building owners will need help planning, installing and maintaining PV systems for their buildings, which will offer a tremendous opportunity for the electrical contractor prepared to fulfill this need.

BIPV advantages

When PV is directly integrated into the building’s exterior elements, it becomes a functioning part of the building’s architecture. Unlike traditional stand-alone PV panels that often look like an afterthought and detract from the building’s appearance, BIPV is part of the building and its architecture. Using BIPV also reduces both material and installation costs because the building elements and PV module are manufactured as a single unit. As a result, there is no need to design and install a separate support system for the PV panels or be concerned about additional structural loads. In addition, windows, skylights and other translucent building elements that are manufactured with integrated PV materials extract energy from incoming sunlight to generate electricity, which in turn reduces building air conditioning loads.

Behind the wheel

There are a number of factors currently driving the PV market, which will continue to do so in the foreseeable future. These factors include the following:

1. Advances in PV technology

PV technology continues to advance, making it increasingly competitive with traditional utility-supplied electric energy. PV conversion efficiency, which is a measure of how well a PV material can convert incident solar energy into electrical energy that can serve building loads, continues to increase. This increase in PV conversion efficiency and the resulting energy output makes PV more economical for the user. Equally important, PV manufacturing technology is advancing, resulting in more efficient manufacturing processes, a greater variety of PV products and lower production costs. Improved manufacturing technology coupled with growing world demand for these materials and increasing manufacturing capacity is leading to economies of scale in PV material manufacturing, a greater supply of PV to meet worldwide demand and PV prices that will continue to drop, making BIPV increasingly economical in the future.

2. Rising building energy costs

Building energy costs continue to rise as the cost of utility-delivered electrical energy increases and demand for electric energy grows in all types of residential, commercial and institutional buildings. Despite our best efforts to conserve energy and replace existing appliances and equipment with more efficient units, our dependence on electronics at home and at work continues to grow, outstripping the gains we have made in electric energy efficiency and conservation. Building loads could increase even further if electric vehicles requiring charging stations begin to replace existing gasoline-fueled vehicles as battery technology advances and gasoline prices continue to rise. As it becomes more expensive for utilities to generate electric power due to increasing natural gas prices and increasing environmental restrictions on coal, PV will become an increasingly economical alternative for meeting a portion of our growing electricity needs.

3. Increasing environmental concerns

Concern about the global environment and the future of our planet has become the focal point of everyday conversation, political debate and media coverage in the United States. People are beginning to demand “green” buildings that are as energy-efficient and carbon-neutral as possible. Developers and building owners are finding environmentally friendly buildings are not only socially responsible but good business from a life-cycle cost standpoint and can also provide a competitive advantage. Potential building buyers and tenants are increasingly concerned about the environment and want to do their part to improve it. As a result, they want an environmentally friendly building that incorporates “green” technologies such as PV. PV integrated into building materials generates electric energy over the life of the building and produces no pollutants.

These three market drivers may appear to be independent but in reality are intertwined. The fact that they are interrelated further reinforces the fact that the PV market is poised for explosive growth in the future. These factors have driven the PV market for more than three decades, but until recently, they have appeared as independent drivers that came and went individually. As a result, interest in PV for commercial, institutional and residential buildings has risen and fallen with these three market drivers.

PV incentives

Even though the cost of BIPV-generated electricity is declining for building owners and tenants, the cost per kilowatt-hour is still high compared to traditional utility-delivered electric energy. However, there are a variety of financial incentives that will help improve the economic viability of PV installations. These economic incentives may be available to building owners depending on the building type and its location. These incentives are available from federal, state and local governments as well as from the serving utility. These incentives can include tax credits and other tax incentives, grants to help defray the initial cost of the PV installation, low interest loans to finance the installation, energy credits and buy-back arrangements, among many others.

One of the most important incentives for PV installations is a net-metering provision in the serving utility’s rate structure. Net metering occurs when a building’s PV system is producing excess electrical energy. The excess is fed back into the utility grid to help the utility offset its current load. When the building’s load exceeds its PV system’s electric energy output, the serving utility makes up the building’s energy deficit from the utility grid. At the end of the month, the building owner pays for the net difference between the energy supplied by the utility and the amount of excess PV-generated energy supplied to the utility grid.

With a net-metering arrangement, the utility grid provides storage for excess PV-generated energy, eliminating the need for building energy storage systems such as batteries. As a result, net metering reduces both the first cost of the PV system and ongoing system maintenance costs over the life of the building. Net metering is particularly important for residential installations where demand for energy is typically low during the day when the sun is out and the PV installation is producing energy and high at night when the sun has gone down and the system is not producing any electricity.

Government and utility incentive programs can be researched using the Internet. For example, the Database of State Incentives for Renewable Energy (DSIRE) is available at This database provides information on all 50 states plus U.S. territories as well as provides links to other databases for federal and other incentives. Information can also be found about PV incentives by researching individual federal, state and local government Web sites as well as the serving utility Web site directly.

New construction PV market

The electrical contracting firm’s PV scope of work for new building construction will depend on the type of materials specified. For stand-alone panels that are mounted on the building or set on the roof, the electrical contracting firm will probably be responsible for procuring and installing the PV panels as well as the balance of the system (BOS), which will include the inverter that converts the PV-generated direct current into alternating current of the proper voltage, frequency and phases as well as all associated devices, interconnecting wiring and raceway.

If the photovoltaic material is integrated with other building materials that are traditionally installed by other specialty contractors or trades such as roofers or glazers, the electrical contracting firm will probably not be responsible for procuring the PV materials or installing them. Instead, the electrical contracting firm will probably be responsible for procuring and installing the BOS. This will lower the electrical contractor’s risk because it typically does not have the expertise or capability to install these materials nor would it want to assume the liability for possible water penetration problems that could occur after installation or the potential mold issues that could develop in time as a result of water penetration.

Retrofit PV market

The future PV market is not going to be just about new construction. In fact, the biggest and fastest growing market could be retrofitting existing buildings with PV systems. This would be especially true in the residential and light commercial building markets where there is significant roof area in relation to overall building surface area. One- and two-family homes could either have PV panels installed on the roof or PV roofing materials that replace traditional roofing materials, such as shingles. For PV roofing materials, the electrical contracting firm should consider teaming with a local roofing company that would install the materials. The electrical contracting firm could then install the BOS.

Light commercial facilities typically have flat roofs, and PV materials can either be integrated into roofing materials or panels mounted directly on the roof. Again, if the installation involves the use of PV roofing materials or roof penetrations for panels, the electrical contracting firm may want to consider teaming with a local roofing contractor to minimize its risk. On the other hand, there are panels now available that have bases that both interlock with surrounding panels and provide ballasts that sit on a traditional flat roof and do not require any roof penetrations for anchoring. Depending on the system used, the electrical contractor’s scope of work will include the BOS and possibly the procurement and installation of the PV panels.

Entering the BIPV market

The electrical contracting firm should be prepared for the coming photovoltaic market. Even though energy prices and average annual sun hours vary across the country, the PV market is growing throughout the United States. More than just the average number of sun hours determines the competitive nature of PV in a given location, so it is not just for the Sun Belt. Other important factors that offset the amount of sun available in a particular location include high energy prices, the availability of incentives and interest in green technologies. The electrical contracting firm needs to be aware of the PV market in its area, know who its potential customers are and how to market its installation services to them. EC

This article is the result of a research project investigating the emerging photovoltaic market that is being sponsored by ELECTRI International Inc. The author would like to thank EI for its support.

GLAVINICH is an associate professor in the Department of Civil, Environmental and Architectural Engineering at the University of Kansas. He can be reached at 785.864.3435 or

About the Author

Thomas E. Glavinich

Freelance Writer
Thomas E. Glavinich was an associate professor in the Department of Civil, Environmental and Architectural Engineering at the University of Kansas. His tenure as one of Electrical Contractor's most trusted and reliable source of industry research end...

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