Parking lots take up lots of underutilized space. However, thanks to recent structural innovations, the solar power industry has put increasing amounts of that underutilized space to productive use. Vast swaths of asphalt nationwide are being covered by structures fitted with photovoltaic panels that generate electricity – while also providing shade for parked vehicles. Installations of parking lot canopies (PLCs) have become an economically viable choice for businesses and institutions weighing renewable energy options.
The growth of the solar power industry has been spurred recently by economic and tax incentives encouraging the use of alternatives to fossil fuels, lower costs for photovoltaic (PV) panels and mounting systems, and greater availability of investment capital. Innovations in the design, engineering, and construction of large-scale PV systems also have tipped the balance in favor of going solar.
One innovation that has stoked growth in solar power in recent years is development of the elevated structure designed for installation over parking areas. PLCs are being used alone or in conjunction with rooftop and ground arrays of PV panels to create electric generating systems to supplement conventional power sources and reduce reliance on the grid. PLCs make sense when there is limited available rooftop and/or ground area for solar, or when the roof conditions are not suitable for a PV system. Often, the most significant open space available at a given site is the parking lot.
On the campus of William Paterson University in Wayne, NJ, for instance, a new 2.7 megawatt (MW) solar power generation facility has been completed (with another 500kW scheduled to be built this year) and is expected to save the academic institution an estimated $3.3 million in energy costs. The system combines newly constructed elevated canopies in five parking lots with ballasted, roof-mounted arrays atop four campus buildings. Comprised of more than 11,000 solar panels, the system was one of the largest energy installations at a U.S. university at the time of construction.
PLC arrays typically carry higher direct cost per installed watt than comparable rooftop or ground options. However, when all other factors are considered, installing a solar carport can still be the most economical solution. This was the case for William Paterson, whose system was designed and installed by SunDurance Energy, a national provider of turnkey solar projects, based in Edison, NJ.
“The University was looking to its many rooftops for significant solar power capacity, but the life expectancy of a comprehensive roof project meant such an approach was not economically viable,” says Steve Bolyai, William Paterson’s vice president for administration and finance. “SunDurance’s creative parking lot canopy solution enabled us to offset more than 10% of our grid electricity usage and significantly reduce our energy budget.”
Parking area solar structures are becoming a common sight across New Jersey, which leads the nation in solar development and clean-technology investment. For example, SunDurance Energy designed and built a 1.2MW PLC at the Mennen Sports Arena in Morris County, in partnership with Tioga Energy who provided the financing.
“We love the clean, simple-line design of the support columns,” states Mennen Sports Arena Executive Director, David Helmer. “It actually adds to the look of our parking lot and the structure provides enhanced energy efficient lighting for evening users of the facility.”
This installation was part of a 3.1MW project that included various PV arrays located at 16 schools and municipal facilities across the county.
Leading manufacturers of solar parking lot structures have seen steady increases in sales, and interest expressed by potential customers is on the rise.
Dana Rudolph, president of ProtekPark Solar, a leading supplier of pre-fabricated parking structures – including the PLC’s at William Paterson – estimates that the company will install projects generating between 15MW and 20MW of power in 2011 compared to less than 10MW a year earlier.
“The interest continues to build,” Rudolph says. “It is becoming more of a normal thought process for people to consider parking lots for solar.”
Among the benefits of using parking lots to host solar panels is they create additional space for power generation where there might not have been adequate roof or ground space. In addition, because they are built vertically, over land already in use, they limit the environmental impact on the landscape. In terms of the actual construction, PLCs can pose some challenges and may not always make sense, which is why it is important to have a qualified solar PV integrator with strong design and construction expertise evaluate the options. The height of the structures create additional wind load (think of the column as a lever); varying ground conditions require careful consideration of the foundation type and depth; and the fact that they are supported over heavily used parking lots increases the importance of sophisticated engineering and construction techniques. Therefore, it is advisable to have PLC projects designed and installed by a firm with in-house engineering capability, deep civil construction experience, and self-perform capability.
Positioning solar power systems in parking areas also can address objections to the projects based on aesthetic or architectural grounds. Concerns have been expressed that solar arrays mar the look of historic or architecturally significant buildings. PLCs eliminate the need for costly or complicated changes to existing structures.
“Every project is manufactured site-specific, and we take a design approach as the aesthetics are a primary consideration,” Rudolph states.
From a financing perspective, solar carports have become increasingly popular, partly owing to the relative ease of acquiring them through a power purchase agreement (PPA). Under PPA contracts, buyers do not incur up-front capital costs for construction because an outside party provides the financing. Instead, customers pay only for the solar energy they consume, and typically at a price less than what the utility may charge in those locations, like New Jersey, with sufficient solar incentives.
Financing methods have been created to streamline the process of integrating solar power. At the Cincinnati Zoo, a solar canopy with 6,400 PV panels covering 800 parking spots was recently installed and will provide 20% of the zoo’s energy needs. The PLCs used for the Cincinnati Zoo were manufactured and installed by ProtekPark Solar, whose prefabricated systems are designed and engineered for relatively quick installation, minimizing construction costs in the field. Once the term of the contract concludes, the zoo has the option to buy the system.
Turnkey solutions like the one used by the Cincinnati Zoo attract customers by removing purchase and long-term financing impediments. As more alternative fuel, hybrid, and plug-in hybrid electric vehicles become commercially available, solar carports could serve the same function as gas stations do for conventional vehicles. Many industry players are developing parking structures that include an electric vehicle charging station. Someday it might become standard to have charging stations for electric vehicles conveniently located throughout parking areas, all powered by the sun.
Parking areas that surround office complexes, shopping malls, schools, and other institutions need not just take up space. As the proliferation of solar-generating canopies proves, parking lots can serve an economically practical purpose by satisfying energy needs using a clean, renewable resource. Perhaps where we have “paved paradise and put up a parking lot” we can reclaim that space and take some strong steps back to making our world a true paradise.
SunDurance Energy LLC