When Bill Hayward needed a new, 50,000-square-foot warehouse at his Santa Maria, CA, location, he recalls, “We just decided we were going to build a green building.” A solar photovoltaic (PV) roof is de rigueur for such an ambition, especially in sunny locales, even if the up-front cost is notoriously high—in this case around $400,000, even after the generous rebate. Such a project might easily take two decades to pay back.

On the other side, though, this was 2001; grid rates were soaring and power was insecure. Hayward’s community and region were well known for an exceptional regard for the environment and respect for preserving it. The 84-year-old company headquartered on the Monterey peninsula had carried the family name for four generations; it was only right to build a structure with recycled materials and free of hazardous substances.

And being green is good for business. Hayward had heard of an environmentally conscious carpet manufacturer in the East who had established a strong product identity based on all-out recycling and production using renewable fuels. Here was an intriguing model for his wood products too. Lumber is just lumber, but local builders who share a regard for the environment would perceive value in the fact that his lumber was processed with renewables. Hayward could build his own business, and in the bargain spread environmentalism. His gleaming new roof would become “a terrific advertisement for the green building concept.”

Four years later, customers indeed do go out of their way to visit his plant and watch a big, silent, clean, sun-powered “smokestack destroyer” in action. Visitors receive the grand tour, complete with extensive metrics displayed on monitors in real time. They learn the finer points of green building design and construction. “It’s kind of neat,” Hayward says, “to take a commodity, which a truss is, and have something really different to talk about. And we do have a story to tell our builders … about our thinking, our philosophy, and our attention to detail. And,” he adds, “when they come to visit, they buy.” Hayward now markets a SolarTruss brand (which, hopefully, will never be advertised with the slogan, “A brand you can truss.”)

Solar Sizing
Always key in any power project is the question how big and for how much (i.e., the first cost and payback). In the case of erecting a new structure there’s no historical energy load to go by, nor billing data for calculating future savings. Hayward’s previous lumber plant for the region (one of eight sites the company owns) was just one-quarter the size of the proposed new one. Hayward guessstimated the roof’s square footage, found some benchmark number related to electrical output, and worked up a scenario for 100% surface coverage and optimized solar energy.

A second key is always who will do it for me and with what equipment? Selecting a solar vendor can be difficult, as a number of competing systems and established companies are out there, but in this case it turned out to be relatively easy: A nearby solar-powered project called the Tehàma clubhouse (owned by Clint Eastwood) sported a 32-kW PV system, and its builder, whom Hayward knew, raved about a “fantastic” firm that did the solar and was based not far away, in Berkeley, called PowerLight. Hayward had contacted other PV firms, but PowerLight was the most responsive, and they so impressed Hayward that, he recalls, “We ended up not even bidding it, because we couldn’t really find anybody else who could bit it the way we wanted.”

PowerLight saw the blueprints and heard Hayward’s intentions—then promptly counseled against aiming for 100%, as it wouldn’t be optimally cost-effective. For one thing, under California’s net-metering rules for solar, there’s a cap of 1 MWh yearly on what the utility will “buy back.” or give credit for, when the power output by the PV exceeds the customer’s needs. Utilities tend to oppose net metering, and in 2001 (as now), there was long-term uncertainty regarding net-metering regulations, so this is a risky proposition for cost-justifying an oversized solar roof. Hence, PowerLight advised Hayward to scale back his goals and strike a more cost-effective balance, which would yield a reasonable payback period—in this case, an array of rooftop cells that would carry a portion of the annual load on the order of 50% or so.

PowerLight specified a total of 902 of its PowerGuard PV modules, to cover 14,400 square feet of the roof. Ranging in size from 22 inches by 27 inches up to 50 inches by 65 inches, these sit atop any flat or slightly angled rooftop (unusual for solar roof technology) and are completely non-penetrating. They’re stabilized against movement by a patented tongue-in-groove assembly. Hayward’s array would thus yield him 118 kW of output; a 100 kVA inverter turns the solar DC into 208-V AC power, and a 112.5 kVA transformer steps it up to three-phase 480-V power for direct connection to the building’s service panel.

At 50% Off, the Price is Right
In simple terms the company’s system cost $800,000 “and some change---or slightly less than $9 a watt,” recalls the lumber company’s director of sustainability Steve Brauneis. At that price it would take several decades to pay back, which explains the rationale for the State of California’s generous rebate formula. As already noted, this flits around, but in 2001 a purchaser of an industrial-strength solar PV system yielding at least 30 kW, could get the greater of $4.50 per watt or 50% of total cost. Hayward’s 118 kW easily qualified for “50% off price marked,” as it were, as well as for a 50% special depreciation tax break and 10% investment tax credit.

On the rebate---which, in typical onsite power jobs nationwide can require extensive paperwork and delays---Hayward describes an absolutely problem-free experience. PowerLight, he says, “worked out everything for us. We wrote them a check for $400,000,” and this covered everything. “We never even had to put up additional money. They were fantastic.”

One more financial note to be added is that, beyond the lavish rebate and write-offs, the tiles also saved Hayward cumulatively tens of thousands of dollars, he guesstimates, in things such as avoided cost for insulation, reduced interior heat loss in the winter, and extended roof life.

Installation of the 902 panels was speedy and problem-free, he recalls, requiring just a couple of days to do because the interlocking tongue-in-groove tiles were positioned as part of the larger construction sequence. The fact that there are no penetrating attachments makes the process “very, very quick.” He adds that subsequent maintenance for the roof---during three-plus years of operation---has been negligible, consisting of getting up on the roof once a year to rinse the panels clean, in order to keep efficiency high; and the panels come with a standard 20-year limited warranty.

Crunch Time: Solar Cost-Recovery
Being very expensive even with subsidies, and yielding power only during sunlight, PV systems require very lengthy payback, on the order of (usually) well over 10 years, although the industry is steadily improving this curve. Hayward concedes the payback was probably a secondary issue to him, given that he was committed to an environmentally progressive structure.

Nonetheless, after about three years of operation since its commissioning in 2002, the roof is proving to be a win-win on both the environmental and the business scores. Brauneis, who keeps tabs on these, reports that as of spring 2005 the cumulative impact on California’s air quality amounts to savings of 190 pounds of NOx, 57 pounds of SOx, and over 100 tons of CO2 emissions which otherwise would have been yielded through conventional utility generation “And that’s just so far,” he adds, as over the course of the assumed 25-year life-cycle, the CO2 figure extrapolates to perhaps 800 tons of CO2 saved—equivalent to 2 million vehicle miles of tailpipe exhaust.

Green benefits do outweigh a purely financial analysis of the project. However, this is not to say that the payback is either disappointing or irrelevant. On the contrary, the roof is highly productive, and original projections are panning out accurately, “if not slightly better than” what the vendor had forecast, notes Brauneis. Operationally, the plant runs two shifts (starting before sunrise), so there’s a daily swing from 0% energy displacement, up to—on optimally sunny days—more than 100% displacement, especially on weekends, “where the meter’s turning backwards into a negative” he says, referring to net metering. For many summer days when the plant is idle, surplus electrical output actually feeds back into the PG&E grid and credit on the company’s electric usage reading. “Quite literally it turns the meter back,” he says. “It’s really fun to look at.”

Monthly electrical loads for the building are in the 20,000-kWh ballpark, and occasionally much less. Monthly kilowatt-hours of PV output are turning out to range from a low of around 6,000 during the winter, up to 14,000 or even 16,000 in June and July. During June 2004—the current “record month” of high PV output—the roof’s contribution of 15,494 kWh amounted to very nearly 100%.

Looking at averages, in the first year of roof operation (2002--2003) the monthly contribution worked out to about 43% of total load; and Hayward’s per-kilowatt-hour rate from PG&E averaged $0.16 that year. Thus the PV production saved just over $20,000. In the second year, the total load declined more than 10%, thus raising the PV’s contribution to an average of over 51% of the load. Brauneis notes that “one thing that sweetened the payback for us” in 2004 was a $0.01 per kilowatt average rate increase, up to $0.17. Owning a PV roof thus “insulates” a business from the full impact of any rate hike. Accordingly, last year the roof saved Hayward almost $22,000.

All in all, then, payback will eventually come, but whether it takes 10 more years or 15, Hayward Lumber is already well-pleased with the total impact.

System Monitoring, Data-Acquisition
Constant oversight of performance is done by PowerLight’s powerful data-gathering tools, enabling Brauneis to study the graphs and numerical displays in real-time on the Web. Kilowattage output and a dozen other metrics are logged. (Example: in spring 2005, after about 36 months of service, the roof had produced 339,419 kWh, valued at about $40,000, or about 57% of the total load. Whenever Brauneis gets into a number-crunching mode himself (as he recently did when pressed for data by this writer), he’s easily able to compare figures against PG&E rates and tariffs, to determine what he’s saving.

Operational uptime status and efficiency are critically important, of course, and these are monitored both at the plant, by Brauneis, and remotely, via the Internet, by PowerLight, too, notes PowerLight’s Adrianne Kimber, manager of systems performance. Should a problem arise at any of the 200 systems the company monitors, corrective efforts will be undertaken to troubleshoot it, she says, “to make sure the system gets back online and the systems are as available as they can be.”

In order to help isolate the source of possible problems, there’s even a “little local weather station” at each installation site. Performance metrics are thus pegged to what would be expected under the given moment-to-moment conditions. For example, if a cloud passes overhead and causes energy output to dip, she says, “we would also see the amount of available sunlight go down, and everything would still match up.”

Even with 200 sites and countless thousands of solar panels to watch over, system glitches are fairly rare, she says, the most common being an inverter outage. These solid-state devices occasionally receive electrical jolts and spikes from the grid or suffer other events, triggering a shutoff. Re-setting is typically automatic. Kimber’s sensors can discern a loss of efficiency due to dirt or debris, or a panel’s outright failure—which, again, is rare, but sets in motion a dispatch call.

Green Refinements
Environmentally, there’s much more to tell. Environmentally friendly components were used from top to bottom---e.g., Bonded Logic recycled denim for insulation, a demand-sensitive hot water heater, green lighting under stringent specs, energy efficient windows, and other electric and heating appliances as outlined under California’s Title 24 energy-conservation standards. Hayward’s building exceeds the Title 24 standard by 40%, he notes, “which means it consumes a whole lot less energy than a standard building.”

In hindsight, though, the HVAC might have been better-designed to duct-in more outdoor air for summertime cooling, Hayward now thinks; another potential opportunity he’s toying with is the very significant rooftop heat the panels generate: This might somehow have been capturable for interior heating.

The moral: questing for ever-greater efficiencies and energy conservation is like any hunt for investment opportunities, and it pays to find specialists who know the latest strategies.

Notwithstanding a few missed opportunities, Hayward’s facility has won a coveted gold-level certification for its design and efficiency, from the US Green Building Council. It has also been recognized by the DOE, the EPA, and the Independent Power Producers---the latter for achieving better than 50% of its energy from onsite renewable source.

Hayward now envisions even greener energy and efficiency in his business, he says. As in his original vision, he now hopes to raise his onsite PV production quite substantially, perhaps even covering all his remaining available roofs with it. He’s budgeting an average annual investment of $100,000 or so to accomplish this, and “over a 10-year period,” he sums up, “we expect to reach 100% solar.”

DAVID ENGLE, a writer based in La Mesa, CA, specializes in construction-related topics.

DE - July/August 2005