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Arizona State grabs solar headlines, but Caltech PV power project pushes forward

17 June 2008 | By Tom Cheyney | Chip Shots

Although Arizona State University's recently announced plan to aggressively add 2 MW of solar power to their electricity scheme in the next year received a fair amount of coverage, a smaller, more technologically potent institution of higher learning is about to flip the switch on the first phase of its own PV power project. The California Institute of Technology plans to add 1.25 MW of rooftop-installed solar panel arrays on seven locations around its Pasadena, CA, campus in the next year, with 200 KW of that coming online in August, according to Jim Cowell, the university's associate VP for facilities.

I first heard about the Caltech plan a couple of weeks ago at the GreenTech 2008 conference, held a few miles from the renowned campus. Cowell described how the plan, part of the school's sustainability initative, would take advantage of a power purchase agreement (PPA) and various rebates and tax incentives to eventually provide more than 2.1 million kilowatt-hours of juice annually, offsetting some 5% of the connected peak load and replacing about 7% of the power purchased from the local utility.

Real photos will soon replace this rendering of
Caltech's first parking-structure rooftop solar array.

The lion's share of rooftop space for the first two phases will come from the top of parking structures: 200 KW/852 modules' worth of Suntech STP 260 boxes for the first buildout, and another several thousand Sharp ND-21642 modules blanketing two structures comprising 770 MW of the 1050 MW planned for the second phase. Each array will be on a raised platform, allowing for parking underneath.

The Caltech campus is a beautiful spot, with lots of green space and leafy shade trees, so the solar project had to take into account the existing canopy. Through a combination of designing around mature protected trees, removing some others with drought-resistant species (if you haven't heard, California continues in drought mode, again), and making sure that the replacement trees provide equal canopy, the PV panels will be installed without wreaking havoc on the extant arboreal lushness and also benefit from more open space to allow more solar photons to rain down on those light-hungry cells.

I contacted Cowell for more information about the program. He reiterated that Phase I is well on its way, with structural and electrical work moving right along (including a SatCon inverter in the Holliston structure basement), the modules in town (but not onsite yet), and project completion set for August.

But the status and timing of Phase II remains a bit shaky, because of the uncertain future of the extension of the solar (and other renewable energy) incentive tax credit (ITC) in the US Congress. The bill has failed to pass so far, most recently in the Senate last week. If it doesn't get through the political process on the Hill, the 30% incentive will end on December 31 and put a major damper on solar power projects throughout the country--including Caltech's second phase.

After telling me he's entertaining three system owner and engineer/installer/operator bids for Phase II, Cowell bemoaned the purgatorial status of the tax credit extension. "We're waiting to see what happens with Congress and the ITC. If the ITC was firm, we'd be able to make a decision alot quicker. But we're getting toward the end of the year and everybody's getting a little bit nervous, so I don't really have a hard timeline to make that decision [on the contractor bids]. If the ITC was firm, I probably would have made a decision by now."

I asked the facilities boss what considerations he factors in when selecting a provider. "We took what I call a 'best value approach.' We looked at price, number of kilowatt-hours the facility would produce, the performance of the firm, the team they had, its strength, the portfolio of projects they'd done. We also looked at the appearance of the proposal, in terms of aesthetically what it was going to look like." Two of the parking structures are very visible, so "how they look is important," he noted.

He also said that "the proposals that did the best were the ones that produced the most kilowatt-hours" (and more kWh means more rebate money), putting to rest any notions of thin-film modules playing a role in the project at this point. (The bid winners for Phase I, by the way, were Solar Power Partners, which owns the system, and EI Solutions, which does the engineering, installation, and operations work.)

Phase III, which is barely on the drawing board but would ostensibly push the solar installed on campus to 2 MW or more, would probably kick in around the end of 2009, according to Cowell--as long as the ITC is renewed and the rebates (such as the $4 per installed watt from the city of Pasadena) are still in place. With the price of cells likely to go down next year, he thinks that might "make more roofs economically viable."

There's also a small-scale student project likely to fold into the third phase, one "where students get involved, working through the feasibility, designing the system, selecting the materials, then doing at least the laying out of the panels," he explains. But the kids won't be doing the electrical connection work. "I'll let them hook the panels up, but I don't know if I'll let them hook the system up."

Although not a research project in the scientific sense, "it provides an opportunity for students to get more involved in trying to make their university more sustainable," Cowell explained. "It also provides an opportunity to use the things they may have learned to design a system that really works, where they'll have to deal with real-world challenges."

He'd like to track the solar output (kW being produced, kWh that's been produced over the past year, tons of carbon offset, etc.) on a "flat screen in the lobby of my building" and "eventually get it onto the sustainability Website."

Although the brilliant minds of the Caltech research community aren't contributing directly to Cowell's facilities-driven efforts--"we're employing current technology, not the ragged edge"--he does have the future progeny of the campus labs gentle on his mind.

"I'm counting on them for the panels I put up 15 years from now," he smiled. Since that's the same duration as the solar PPAs in place at Caltech, that's not entirely an offhand comment.