SunPower (SPWRA) saw an increase of more than 10% in its stock price on March 15. This trend was seen across almost all companies in the solar industry, including SunPower's competitors FirstSolar (FSLR), SuntechPower (STP), and Yingli Green Energy (YGE).

Our price estimate for SunPower's stock is at $14.41, about 10% below its current market price.

First Solar (FSLR)is engaged in the manufacturing and sale of solar modules with an advanced thin film semiconductor technology. The firm also designs, constructs and sells photovoltaic solar power systems to customers around the world. First Solar competes with other solar industry players like SunPower(SPWRA), Suntech Power(STP) and Yingli Green Energy Holding Com.

They don't all work out. Suntech Power Holdings Co. Ltd. (STP), first discussed here on July 28, 2009 at a price of $19.24, was stopped-out at $8 in late August, for an 11-point loss.

Suntech's shares, a high-risk stock, had recovered to about $11 in mid-summer after plunging in bear-hug fashion this spring from about $16 to $8.40.

The calculation in the summer was that photovoltaic cell manufacturer Suntech's long-term business prospects in China would offset short-term hits to revenue, due to price declines.

It's all well and good to say a stock posting improving earnings is a good buy with upside potential. But how much upside? The truth is that picking stocks capable of dramatic gains -- potentially as much as doubling your money -- is much harder. That's because charts don't offer much information for big moves like this, and efficient market theory argues against such short-term performance.

But finding doublers, while difficult, is not impossible.

This morning, JA Solar Holdings (JASO) announced that it has signed multiple supply agreements with "several customers" to provide solar cells in 2011. The company will supply the solar cells from January 2011 through December 2011, but they are accompanied with prepayments or the delivery.

The company's CEO Dr. Peng Fang stated, "We are seeing very strong demand for our technologically advanced, high-quality products from our diverse global customer base ... Our customers view JA Solar as a reliable supplier partner and rely on JA to provide them with their 2011 product requirements."

A stock with room to rise, such is the current condition of First Solar Inc. (FSLR). On the one hand we have an analyst consensus of hold, due to the loss of subsidies in the company's primary market and remarkably low natural gas prices. On the other hand, we have overt optimism about the company from none other than Dow Jones, and brokerage price targets that go as high as $200. In cases such as this, I like to take a step back to look at the big picture.

FSLR is just beginning to rise from a 52-week low. The company's balance sheet is rock solid, its reputation is gleaming, and the market for its goods is strong. Estimates indicate that the global volume of solar installations slated for 2010 will be nearly double the 2009 level of 6.4 gigawatts.

The U.S. Department of Energy is becoming a major venture capital player. The government agency is shooting to dish out -- through loans and grants -- more than $40 billion to companies in the clean technology space. The DOE is looking to fund a wide range of businesses in this space from solar panels to electric cars. In the first three quarters of this year, the department pushed out $13 billion under this model, far ahead of the $2.68 billion that venture capital funds pumped into the sector.

So far, more than 40 companies involved in the auto industry have pursued DOE cash. They have their collective eye on the $25 billion in federal low interest loans that have been allocated to the sector.

If you still doubt that the next bubble will be green, check out the latest from California. Green and clean technology gigs surged 36% from 1995 to 2008, beating the state's overall 13% job-growth rate for the same period, according to Silicon Valley-based research firm Collaborative Economics. Since California's on the leading edge of this sector, many see it as a sign of things to come for the rest of the country.

As of January 2008, there were only 159,000 green jobs in California, less than 1% of the state's total, following year-over-year growth of 5%. But, during that same period, total jobs in the state dropped 1%, suggesting that jobs in sustainability just might be more sustainable. Though these may seem like small numbers, keep in mind that the green sector job market is twice the size of the state's biotech presence and two-thirds the size of the software industry.