The Role of Incentives

The U.S. federal government offers incentives only in the form of tax credits, leaving most of the incentives up to the states and individual utility companies. Since the range of incentives varies wildly place to place, stakeholders need to be well-versed in what rebates, grants, and taxbreaks are available in a particular location. For example, in California there is a plethora of tax breaks and rebates, net-metering is widely available from utility companies, and regulations for power-purchasing agreements are in place. But many states have few incentives, spotty access to net-metering, and no opportunities for third-party agreements. (The North Carolina Solar Center maintains a state-by-state summary of incentives with an interactive map at the Database of State Incentives for Renewables at  dsireusa.org).

In areas where there aren't enough incentives to make PVs viable, NREL's Van Geet points to the importance of designing buildings solar ready. "In a state like Arkansas, you're less likely to use solar because of cheap coal-fired power and the economics of incentives aren't good there," He continues: "You should at least plan for PVs because it doesn't cost anything by designing for the weight of the future PV system." Polk Stanley Wilcox Architects designed the LEED-Platinum Heifer International for PV (see p71). "We looked at PV initially but the payback didn't meet our goals," relates principal Reese Rowland, AIA. "We recognized that we could prepare for a time when costs would come down."

For residential pitched roofs, designers should add about 2 pounds per square foot. Flat commercial roofs require about 4 pounds per square foot additional capacity. NREL has a guide to making buildings solar ready that's available at nrel.gov.

The International Boom

Recently, the U.S. has made significant gains in the number of PV systems installed. Growing at 30 to 40 percent a year, we're now third in PV installations. However, that's still behind the smaller European countries of Germany and Italy. Germany's solar surge is fueled by generous incentives aimed at curbing greenhouse gas emissions. Also, European countries are interested in curbing dependence on Russian fossil fuel. China has become a top producer of inexpensive PV modules. Despite its enormous economy and its penchant for headline-grabbing green projects, China doesn't rank in the top tier of PV consumers.

The potential in the U.S. is tremendous. Big box retailers and other corporations are beginning to make green flourishes with PV installations. Wal-Mart, with some 81 million square feet of roof area, has installed panels on 31 stores with another 20 to 30 slated for thin-film installations. And the much publicized Google campus has a 1.6 megawatt system that will power up to 30 percent of its facilities. However, the majority of these projects remain in states like California, where the incentives are strong.

The crossing of the nuclear threshold in the Duke University study shows that PVs are viable in a state with average renewable energy incentives and moderate solar conditions. It is another bellwether that PVs, with their near universal availability, are going to play a key role in our energy future. That future was alluded to in a recent double-page ad in The New Yorker magazine that showed three lithe girls under an umbrella taking refuge from North African sun. The headline asserts: "0.3 percent of Saharan Solar Energy Could Power Europe." This pronouncement comes not from the solar energy industry, but from a bank. The gist of the ad is that, with some smart financing, we could use the energy that's warming the planet and transform it into renewable energy. While the answers to climate change and our dependence on fossil fuel are more complicated than the ad implies, photovoltaics are proving to be one solution worth investing in.

Michael Cockram writes on sustainable design and green building practices. He is an adjunct professor of architecture at the University of Oregon.