With the rush toward viable renewable energy solutions and concepts like net-zero energy buildings become more a reality, owners and designers are looking for new and better ways to minimize reliance on the utility grid. Although wind and geothermal certainly are part of the conversation, many are looking to solar energy.
The metal roofing industry long has been working with rooftop solar photovoltaic installations. As the technology becomes more efficient and the applications more prevalent, the industry finds itself in a unique position; it can lead the charge toward buildings that are able to generate their own power.
Last year’s METALCON International in Tampa, Fla., provided a special focus on solar solutions working with metal components and systems. At the Solar Bay display, attendees were able to see examples and applications in action. During the show, the staff of metalmag was able to sit down with a unique group of individuals, representing different viewpoints about the PV installation process. Tony DeLoach, president of WES Industries, Sarasota, Fla., offered the perspective of a renewable energy firm focused on the solar PVs themselves. Rob Haddock, chief executive officer and president of S-5!, Colorado Springs, Colo., as well as the director of the Metal Roof Advisory Group, also in Colorado Springs, spoke for the attachment side and Ken Buchinger, vice president of business development and R&D with MBCI, Houston, represented the roof panel manufacturer’s perspective.
Rob Haddock of S-5! discusses the advantages of standing seam metal roofs for solar PV installations.
Credit: Shawn Haddock
Following are some highlights from our conversation about the state of rooftop solar PV installations, and why metal roof solutions hold an advantage.
MM: When did it occur to you that solar photovoltaic installations would integrate well with metal roofing solutions? What made it an appealing combination?
Haddock: I first became aware that PVs were being used on rooftops in the early- or mid-90s when a guy from [Frederick, Md.-based] BP Solar talked to me about using S-5! clamps on an installation. It made immediate sense to me because it was such a perfect marriage. It’s so easy to mount PVs on a standing seam metal roof. It’s the only commercial roof type that’s going to have a service life that exceeds the service life of the PV. With any other commercial roof type—and by that I mean low-slope commercial roof types like plastomers, elastomers and modified asphalt products—none of them have a service life in excess of 20 years. But metal does.
DeLoach: For me it made sense from the beginning, based on the longevity of the roof. The alternatives of putting PV on applications such as asphalt shingle tiles or ceramic tiles or concrete tiles are somewhat problematic, both from an attachment and warranty standpoint. The PV panels come with a 25-year mandatory warranty, so you want to put them on a product you don’t have to remove and reinstall 5 or 10 years from now; that would make the whole project cost prohibitive. So metal roofs are probably the only things out there that have the proper life cycle to allow us to put a one-time application of an installation and see it go from first-cost phase to a break-even point in a reasonable amount of time.
Buchinger: Although I’m not sure I can pinpoint when I realized PV was a perfect complement to our existing product line, I can certainly explain why it is. In addition to the service life benefits of a metal roof, you also typically have a roof with a slope, which allows the PV system to be somewhat self-cleansing during rains but not too steep to prevent safe access for any required maintenance.
Credit: Shawn Haddock
Of course, we’ve touted the performance traits of metal roofing for years: the low life-cycle costs, the durability and low maintenance. For the environmentally aware consumer, the recyclability of steel, level of post-consumer content and energy efficiencies when using a cool colored roof provide added advantages. And I still think metal roofs provide some of the best aesthetic options for the designer. These qualities hold true for PV or any application I’ve found so far.
MM: What is a common return on investment period right now for these kinds of rooftop PV systems?
DeLoach: It differs by state because some states have SRECs [solar renewable energy credits] and other credits available. In New Jersey, the whole state has SRECs and credits that make solar very economical and have a buyback of four to five years, while some states, like here in Florida, have a buyback period of 12 to 14 years depending on power consumption because we don’t currently have SRECs.
The easiest part of a solar PV project is putting together the solar cells themselves. It’s literally a plug-and-play wire erector set. Tying into the grid gets a bit complex, but really the most challenging thing is working out the total life-cycle liability risk cycles and total life-cycle cost. We’re doing a project in New Jersey that has 12,500 panels on it. Can you imagine having to go up there in 5 to 7 years and take off all those panels to replace a TPO roof? Not to mention, on that kind of roof you’re going to have to turn loose a bunch of workers putting on average 6 to 8 penetrations per panel through the roof membrane. As the developer, when the building owner says “I’d like a warranty for 20 or 30 years,” and you look at a roof with countless penetrations compromising its integrity, that idea leaves the decision tree.
Haddock: We’ve always been worried about our cost competitiveness in the metal industry and have been a little embarrassed that our roofs cost a few dollars more than TPO or a bituminous roof or another single ply. But the fact is that initial cost is peanuts when you consider the service life of those PV modules is in excess of 30 years, so if the roof life expires within 12 to 18 years, then you have to dismantle the PV, replace the roof, and put the PV back. And you have to do this two or sometimes even three times before the life of the PV expires.
The other huge advantage with standing seam metal roofing is that it’s penetration free. You can throw a huge PV array on your roof with no penetrations. With other kinds of roof types, you have to punch the roof full of holes to reach through with the PV racking and attach to the building structure. And that has obvious drawbacks.
Buchinger: There are far too many variables at play with any building. Fortunately, there are modeling calculators available that will take into consideration your building’s unique circumstances. They’ll look at the roof orientation, average energy costs for the area, energy usage rate of your current building, etc. You should also consider additional costs or savings not necessarily included, such as local incentives, life-cycle costs, installation comparisons for new applications and longevity of the PV substrate.
MM: Are roof penetrations a real issue on these installations? How do you handle them?
Haddock: A lot of the PV integrators are technical guys and they’re really into the electrical end of things and all the efficiencies; they may not know very much when it comes to roofs. They sometimes think all the magic is in modules and inverters and the angle of the sun. And that’s all great, but you still have to think about the rooftop that’s protecting the building and the warranties involved with that. There’s a real need for the PV industry to come together with the roofing industry and talk. You can’t just chop a hole in a roof, run cable down it, slap some putty over it and think everything’s OK.
DeLoach: It’s a good point. You wouldn’t think for a moment to approve an electrician to put together a roof, but in many cases electricians are being turned loose to modify roof conditions. There’s a need for some cross training between the roof contracting and electrical contracting industries.
Buchinger: Of course, we would prefer to avoid penetrations whenever possible. In some cases, penetrations may be unavoidable and that’s okay if it’s done correctly. But you can’t just put a hole in a roofespecially a metal roofwithout considering the consequences. In this case, the electrician will most likely be installing the complete photovoltaic system. For this to be a success, he should coordinate with the roofing contractor in advance of the roof installation and preferably before the roof design has been completed. That way, they can work together to determine the best placement for the equipment, as well as ensure that all of the proper load requirements have been considered. If the roof is already in place, the roofing contractor should still be consulted. Often, his responsibility for the roof is not over once the roof is installed. An electrician may unknowingly make a penetration that voids the weathertightness warranty. If the roofing and electrical contractors work together, the risks will be lowered and ultimately yield a better solution for the owner.
Haddock: You have to penetrate membrane roofs all over the place. There is no choice. But I’ve been on enormous PV jobs on metal roofs where the roof wasn’t penetrated a single time. Not for the mounting of the panels and not for electrical because the electrical chases just went over the eave and over the side of the wall. I’m talking thousands of PV modules mounted on a roofall the wiring, cable trays and the whole nine yards and not one penetration through the roof. That is a tremendous advantage our roof type has over others. When you look at roof service life compatibility with PVs, zero penetration and cost, it’s a perfect match. Cost is a big one. It’s one thing to say we’re better because of A, B and C and you should be willing to pay more, but we don’t have to apologize for cost in this case. We’re actually a lower cost than the alternatives.
MM: You mentioned that using a metal roof with a PV system has a lower cost than the alternatives. Are you referring to up-front cost or costs over the life of the roof?
Haddock: It’s both! From day one, first dollar, if you’re doing PV and a new roof on new construction, the cheapest way to accomplish the two is PV and standing seam metal.
Buchinger: That’s a key distinction. Don’t just compare the up-front costs of a metal roof to a membrane or a built-up roof. That’s misleading. Making a decision on just the upfront cost of the roof can result in a bad decision because the metal roof will probably cost a little more up front. You need to consider the life-cycle costs, which take into account the life span and maintenance costs of the roof. When you do that, metal is a clear winner. When you add in a PV system, as Rob stated, the lower attachment costs on a standing seam metal roof makes its metal a clear winner in up-front costs as well.
Participants in the solar round-table discussion included (clockwise from right) Ken Buchinger, MBCI; Russell Ellis, metalmag; Jim Schneider; metalmag; Keith Lipps, S-5!; Tony DeLoach, WES Industries; and Haddock.
Credit: Shawn Haddock
DeLoach: I was speaking recently to one of the largest, if not the largest, solar installers in the U.S. and asking about roof warranties and how they deal with them. They flat out said, “We walk away from 98 percent of our proposals because of warranty issues with the roof.” Basically, if it isn’t metal, it’s not commercial. If it’s a membrane roof with 6 or 8 years left on its life cycle, they simply won’t do the project.
One of the speakers at METALCON said that 80 percent of all solar built in the U.S. today has been through purchase power agreements. This company I’m talking about only does PPA projects, so if they decline 98 percent of the proposals they could do because of warranties and the fact that it isn’t a commercial metal roof, that’s pretty significant. That alone tells me it drives the market to a standing seam or metal commercial roof. Going in and having a direct mount is the lowest cost. With any other type of roof, you have to do all the penetrations and you have to bridge and get the additional support in there. Everyone relates to price per watt; you can pencil it out all day long and from a price-per-watt standpoint, it’s the cheapest solution going.
Haddock: There are enough savings in the PV part of the equation when you’re mounting to standing seam metal to pay for the premium of the metal roof cost over another roof type. That’s why it’s less expensive on the first dollar. The real bonus is when you consider all the roof replacements you have to do with traditional, low-slope roof types. When you compare that, the savings are almost unbelievable.
DeLoach: To make an analogy, would you go out and buy a Rolls Royce and then buy the cheapest tires you could find and drive 100 mph down the road? With PV, you’re putting in something that’s an asset. In fact, it’s an asset with a federally mandated 25 year warranty, so why would you make that kind of investment and put it on a less than optimum support structure? It just doesn’t make sense. From a financial standpoint, it makes sense to go the extra mile and put on something that’s going to support it and give it its full life cycle.