This year's Intersolar North America show, colocated at the Moscone Center with Semicon West, should have more than 20,000 attendees. That's up from 17,000 a year ago. The show had 580 exhibitors, an increase of nearly a third from 2009. Markus Elsässer is CEO for Solar Promotion International, the company that puts on Intersolar shows all over the world. He's not surprised by the rapid growth in the three years the show has been running along with Semicon West. "We think the market here has huge potential," he said of US solar prospects. After all, the country has sunshine, money, infrastructure, manufacturing, and a need for clean, renewable power. Put it all together and that spells what should be a booming market for photovoltaics. That promise explains why Intersolar North America has grown to rival Semicon West in size. Intersolar North America 2010 attendees gather in the lobby of the Moscone Center in San Francisco. (Photo: Intersolar) While that photovoltaic potential still has yet to be realized, there are signs that it may soon be. Elsässer predicted the US will triple it capacity growth this year, moving from 500 MW to 1.5 GW. That surge has to be put into context, however. At the opening presentation for Intersolar North America, it was pointed out that that Germany will add 8 GW of solar power this year. California leads the nation in the growth of solar power. Sue Kately, director of the state solar trade organization CALSEIA, noted that California is doing well when compared to the rest of the country but not when compared to Germany. In her presentation, she vowed to change that. "I really want to get California going - to be building gigawatts per year, not megawatts," she said. If she succeeds, she may have company. The US solar industry has a goal of installing 10 GW of power a year by 2015. Part of the reason why the US market may take off soon, despite a lack on the national level of the type of incentives found in Germany, is that solar power is dropping in price. Data over the last 20 years shows that doubling the installed solar capacity cuts the cost by 22 percent. The rapid recent growth in photovoltaics would suggest price decreases of as much as 10 percent a year over the next few years. There also are indications that utilities, cities and states are not waiting for a national plan to emerge. Some are adopting feed-in-tariffs, the type of incentives used so successfully in Germany. In her talk, Kately mentioned programs in Florida, Oregon, Vermont, and the capital of California, Sacramento. There, she said, the municipal utility district announced it would accept 100 MW of feed-in tariffs and was oversubscribed with applications within four hours. However, what goes into the US market is likely to be more mixed than what has been the case elsewhere. That's partly a function of the continuing maturation of the technology and partly a result of the nature of sunshine in the US. Ryne Raffaelle, director of the National Center for Photovoltaics at the National Renewable Energy Laboratory in Golden, Colo., noted during that upstate New York gets more sunshine than Germany. The American Southwest is bright red on the same scale and so it might be best exploited by a different type of technology, one that concentrates light. "I think CSP (concentrating solar photovoltaic) is going to take off soon," he said at a North America photovoltaic fab manager's forum held as part of show. Raffaelle also noted that as much as half of the cost of a III-V compound semiconductor-based photovoltaic is in the wafer, the base material that converts photons into electricity. Thus, either a concentrating or a thin film approach might help cut costs by eliminating some of that material. If North American manufacturers are going to take part in the expected US boom, it likely won't be through modules or panels built using crystalline silicon. Instead they'll probably do so using a thin film or some other approach. There are no large established players in this area and there's a potential cost benefit in using less material or some other innovation, two important advantages. Indications of this come from materials suppliers. Houston-based Air Liquide Electronics sells gases, chemicals, and turn-key processing systems into the photovoltaic manufacturing market. The difference in focus is evident from those sales and potential sales. Mark Ohlmeier, the company's general manager for photovoltaics business development, said of North American manufacturers, "My opportunities are much more in thin film than in crystalline silicon." Hank Hogan hank@hankhogan.com