Designing and Deploying Carport-Mounted PV Systems
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Not all rooftops are well suited to host a PV array. This is part of what makes elevated solar support structures—like PV carports, canopies and shade structures—an attractive option for system integrators and potential customers alike.
Rooftops are space constrained and often present siting, shading and waterproofing challenges. On one hand, if the existing roofing system is more than a few years old, it may need replacing as part of the PV installation. On the other hand, if the roofing system is new, then retrofitting a PV system may void the roof warranty. The structure itself may be inadequate to support additional loads. The alternative, of course, is a ground-mounted PV array. However, many businesses and institutions do not have large areas of unused and unshaded land that they can dedicate to a PV power system for 20 to 30 years.
What these potential customers likely do have are parking lots, parking garages and storage or maintenance facilities for fleet vehicles. These vast fields of asphalt and concrete are ideal for elevated solar support structures. Regardless of location, covered parking is generally preferred to uncovered parking because it provides protection from the sun, rain and snow. Most customers value this convenience, even if they cannot justify paying a premium for it.
Part of what makes the value associated with elevated solar support structures so compelling is that it allows many US customers to receive a benefit like sheltered parking without having to pay full price. At least through 2016, as long as a solar support structure is constructed for the express purpose of generating electricity, it typically qualifies for a 30% federal tax credit. In addition, commercial customers can depreciate parking lot improvements. When they lease or finance carport-mounted PV systems using a PPA, customers often benefit from having covered parking without making any up-front payment.
To better understand the solar carport market, and the associated design and deployment challenges, I reached out to system integrators, carport vendors and industry professionals working where the structural steel meets the road.
If you think that solar carports represent an insignificant niche market, think again. In the summer of 2012, SunDurance Energy commissioned an 8 MW elevated solar structure that provides 32 acres of covered parking at Rutgers’ Livingston Campus in New Brunswick, New Jersey. This is one of the largest university-sited PV systems in the country.
It also bears mentioning that many solar carport projects, such as installations hosted at facilities operated by the US Department of Veterans Affairs or the California Department of Education, are not funded through state incentive programs. As such, these federal, state and municipal projects present another revenue stream for solar companies that are strategically positioned to take advantage of the business opportunity.
Who are typical solar carport customers and what is driving them toward this solution? Are some regions or market sectors hotter than others?
“SPG Solar has designed and installed carports for customers in California, Arizona and New Jersey. Typically, customers select a carport if they do not have a roof suitable for a solar array or an area of their property that they can dedicate to a ground-mounted PV system. Hotels, distribution centers, school campuses, government facilities and water agencies have all installed solar carports to lower operating costs and provide a hedge against rising energy rates. Solar carports are also a visible symbol of an organization’s sustainability efforts.”
—Danny Meyer, project designer, SPG Solar
“Most market activity is in those states where there are rich incentives, and in the West and Southwest where shaded parking is highly valued. Other drivers of demand include rain protection, demonstrating to customers that you have gone green and ARRA [American Recovery and Reinvestment Act] money still trickling through the government.”
—Casey Marshall, co-founder, Crider Americas Solar