'Electricians, plumbers, roofers - we can put these people back to work," said Rhone A. Resch, president of the Solar Energy Industries Association.

Resch's group, based in Washington, is teaming up with IEEE, the electrical-engineering society, to cosponsor this year's PV America (PV = photovoltaic = solar electric) conference and trade show at the Convention Center, 1101 Arch St.

The groups say they will bring 3,000 sun-power businesspeople and engineers here next week, June 8 to 10. The 135 solar-themed exhibits are open to the public June 9, noon to 8 p.m.

The brains and the business muscle of the young but growing solar business will be passing through Philadelphia, including Jigar Shah, founder of Goldman Sachs Group Inc.-backed solar-electric producer SunEdison L.L.C., of Beltsville, Md.; Department of Energy solar czar JoAnn Milliken; ex-CIA chief turned "energy independence" advocate James Woolsey; solar analysts from Morgan Stanley and other Wall Street firms; and Tim Anderson, University of Florida solar-engineering scholar, who'll run IEEE's 34th yearly Photovoltaic Specialists Conference next door to the trade show.

Between debating new systems and swapping ideas on how to finance expansion, they'll be trying to sell you home and business solar-electric systems, many of them eligible for state subsidies and federal tax breaks that can shave half or more from the cost of installation.

Philadelphia isn't sunny Phoenix. Why meet here? Because Pennsylvania and other northeastern states took the lead in subsidizing solar energy when the federal government wouldn't, says Resch. And those subsidies reach further now, thanks to federal tax breaks offered by the George W. Bush administration and extended by President Obama.

Why should solar get public money? If we won't subsidize it, the U.S. industry will be crushed by government-sponsored European and Asian competitors, Resch's group says.

Visa vs. MasterCard

You'd think investors would stay away from credit card stocks. As Advanta Corp., of Horsham, cancels its cards, the largest card lenders - American Express Co., Bank of America Corp., Capital One Financial Corp., Discover, and JPMorgan Chase & Co. - are also losing money as industry default rates climb above 10 percent.

But the Visa and MasterCard payment systems, which operate the electronic networks that connect spenders, stores, and the banks, are still highly profitable.

They don't make loans; banks do that. But they still get a cut of every credit and debit card transaction that runs through their card networks. Visa and MasterCard get paid, even when a borrower defaults.

And card use is still rising.

"It is rare to find a large-cap company that can grow 20 percent per year during a recession," while still posting operating margins above 50 percent, Janney Montgomery Scott L.L.C. analysts Thomas C. McCrohan and Leonard A. DeProspo told clients in a recent report urging investors to buy Visa shares yesterday.

But they see warning signs. Growth has slowed from the red-hot rates of the mid-2000s. Card-use fees "are poised to decline" because of competition abroad. They see "the growing hostility toward the credit card industry in Washington." And outraged merchants tired of paying a couple of pennies off every dollar accuse the payment networks of stifling competition.

But the Janney analysts say Visa will likely keep its sky-high profit margins. "Visa spent more than $400 million on consultants last year," McCrohan told me, and it can afford to cut the costly consultants, trim ads and marketing, and shut regional operations to protect profits. Though that won't much help the U.S. economy.

Visa's smaller rival, MasterCard, isn't so flexible. Though its stock is cheaper than Visa (compared with profits), Janney rates the suburban New York company "neutral" because of "decelerating volume growth." They expect MasterCard will cut prices, but it won't catch market leader Visa soon.