Is the Cost-Effective DIY Solar Panel Within Reach?

If you wanted to train to be a solar photovoltaic panel installer at the absolute finest institution nationwide—the Ivy League school of solar installation training—where would you go to learn? That question, posed to industry experts at the recent PV America trade show, generated a unanimous response: The North American Board of Certified Energy Practitioners, or NABCEP. There, an aspiring installer can earn the only national professional certification available for solar-thermal and solar-photovoltaic work. Graduates have mastered such concepts as sizing an inverter to properly convert the panels’ DC power output into usable AC power, as well as how not to get killed when working with live 400- or 600-volt wiring.

But as solar-panel technologies advance, will that much training remain necessary? Just before PV America, the firm Andalay Solar debuted its new AC panel, which eliminates the need for elaborate DC wiring and large, system-wide power inverters by building micro-inverters into each individual panel. For buyers willing to dip a toe in solar, the panels can be installed one at a time. For installers, the built-in racking, wiring and grounding allows a full 3-kilowatt system of about 20 panels to be installed by a two-man crew in less than a day. Andalay Solar CEO Barry Cinnamon expects such developments to lead to plug-and-play panels on U.S. home-store shelves within a few years. “Solar panels today are where computers were in the mainframe era,” Cinnamon says. The idea of the personal computer emerged when engineers combined several bulky, discrete parts into one machine, as the Andalay panel has done, he says. He expects further innovation to reduce the size of the machines, the time of installation, and, perhaps most critically, the cost to put them on the roof.

For now, though, solar-photovoltaic jobs remain safely in the hands of professionals. In the future, a DIY hookup might “never happen,” John Wright says. Wright, an associate with Hudson Valley Clean Energy, the largest solar installer in New York state, says: “Somebody who doesn’t know what they’re doing can get killed. We’re not talking about a little shock from a low-voltage appliance.” Wright is referring to the live high-voltage DC wire essential to a traditional inverter setup, and admitted that “someday, maybe” a panel with a built-in micro-inverter could be handled by an amateur. But even Andalay chief Cinnamon doesn’t expect utilities to allow homeowners to tie the panels to a municipal grid, a step Wright described as a “pretty rigorous process.” He should know—Hudson Valley’s lead photovoltaic engineer is NABCEP-certified.

Price Breakdown

Everyone in America receives a 30 percent tax credit on solar equipment purchased and installed by the end of 2010. State incentives can further compound the savings.

Price per unit /// Between $717 and $787 before the 30 percent federal tax credit. Afterward, the price drops to about $500.

Price per watt /// $4.50. Andalay Solar CEO Barry Cinnamon expects imminent price reductions to pull that number closer to $4.10 per watt. With the 30 percent federal tax credit, the price works out to about $2.87 per watt.

Kilowatt-hours per year /// A single panel puts out 175 watts under optimal conditions. Averaged through the year under variable conditions, the panel puts out 1.43 kilowatt-hours per watt, or about 250 kwh per year.

Payback period: The Energy Information Administration lists average U.S residential electricity prices at 11.23 cents per kwh, as of February 2009. A panel that puts out 250 kwh a year saves $28.08 annually at that price, making the payback period just under 18 years on a $500 panel. (The rebate, which everyone receives, lowers the payback period from over 25 years at $717 or 28 at $787) In San Francisco, the top-tier electricity rate is 44 cents per kwh, shortening the payback period to just under five years.

Drawbacks: Variable power output. Less sunny climates can produce less than the 250-kwh-a-year average. Less than a quarter of the sunlight hitting a panel converts to electricity.