Two days after getting a widely reported plug from California Governor Arnold Schwarzenegger, SunPower’s stock jumped 55 percent after going public at $18 per share.

The shares rose $8.18 to $26.18 in recent trading. Earlier, they touched $28.01—55 percent above the offering price.

SunPower got a timely boost from Governor Schwarzenegger on Tuesday, when the movie star-turned-politician praised its solar chip during a trade mission to China (see Governator to China: Go Green). The same day, SunPower raised its price expectation for the upcoming IPO by $4 to a range of between $16 and $18 per share from the previously expected range of $12 to $14 per share.

The Cypress Semiconductor subsidiary offered 7.7 million shares in the offering managed by Credit Suisse First Boston, Lehman Brothers, SG Cowen, and First Albany Capital.

The solar company is one of several to announce IPOs this year, and the warm welcome is the latest example of rising investor interest in the solar energy industry.

Most of the solar IPOs this year have been German companies. In October, German solar-cell company Q-Cells saw its shares rise 27 percent to €48.09 ($57.81) on its first day (see Q-Cells IPO Raises $288.5M). In recent trading, its shares were worth €48.85.

ErSol launched its IPO the same week, watching its stock grow to €65 from €42 on its first day. In recent trading, its shares were worth €40.20. Shares of Conergy, which launched at €54 in March, recently traded at €81.93.

Suntech Power, a Chinese solar company, is expected to announce its IPO in the next few months.

Attracting Investors

SunPower’s debut is “great news,” said Colin Murchie, director of government affairs at the Solar Energy Industries Association (SEIA).

“This gives investors another vehicle to tap into a lot of excitement in the field,” he said. “Along with Q-Cells’ IPO in the German market this year, I think it’s a real indication this has turned into a significant industry, and one that will attract a lot more capital.”

SunPower claims its solar cells are between 20 percent and 21.5 percent efficient, meaning it converts about a fifth of the sun’s captured energy to power. That compares with an industry average of about 15 percent, said SEIA president Rhone Resch.

The company has also made aesthetics a priority, which is especially important in the residential market, Mr. Murchie said.

Like most of its competitors, SunPower uses metal contacts to collect and conduct energy from the sun. The difference is that SunPower puts those metal contacts on the back of its cells, away from the sunlight, to avoid reflecting sunlight away.

Rapid Expansion

The company is expanding rapidly and has secure supplies of polysilicon, a big advantage with industry analysts predicting a shortage, Mr. Resch said.

“It certainly appears they are in a good position to have the feed stock to support their growth,” he said. “That’s something that separates companies: can you grow or not? If you can produce it, believe me, there’s a market for it.”

He said Cypress Semiconductor still owns 87 percent of the company. Cypress’ stock was down $0.33 to $15.74 in recent trading, but Mr. Resch said he suspects that could change once investors “put the pieces together.”

As energy prices have remained high around the world, cleantech investment has soared. The Cleantech Venture Network expects North American investors to feed $10 billion of venture capital into cleantech during the next four years, and stock prices jumped about 185 percent last year, according to the Progressive Investor (see Cleantech Funds Seen at $10B and DFJ’s $150M Cleantech Fund).

Mr. Murchie said the market is nowhere near saturation. “There’s a whole lot of investor interest in cleantech, both on the public markets and the venture capital side, that I don’t think is nearly exhausted,” he said.