Buoyed by a mammoth 30 percent gain yesterday on very positive quarterly earnings, First Solar (NASDAQ: FSLR) and other solar stocks continued their rise today.

First Solar was up an addition two percent in early trading, at $232.14.

First Solar beat the street and rewarded investors with a $52.90 (30.13%) gain with earnings of $62.9 million, 77 cents per share, compared with $8 million, or 12 cents per share, in the year-ago quarter.

Revenues for the fiscal year ended December 29, 2007 were $504.0 million, up from $135.0 million in fiscal year 2006.

The rally continued in after market trading with additional gains.

According to the company's press release, quoting Michael J. Ahearn, Chief Executive Officer of First Solar, "During the fourth quarter of 2007 we benefited from the full capacity and economies of scale of our Frankfurt/Oder plant. This combined with continued throughput and conversion efficiency gains afforded us strong operating leverage and decreased our manufacturing cost per watt by 12% year over year to $1.12 per watt in the fourth quarter of 2007, further solidifying our cost leadership position in the industry."

Significant solar sector gains at close of trading yesterday, and performance as of this morning:

• Akeena Solar - 5.56% yesterday, 4.24% today
• Evergreen Solar - 12.17% yesterday, 0.4% today
• LDK Solar - 6.32%, 2.44% today
• Canadian Solar -12.87%, 2.46% today
• China Sunergy Company - 6.87%, 1.29% today
• Yingli Green Energy Holding Company - 16.6%, 2.11%
• SunPower, which itself today announced a silicon supply agreement with China's Qingdao DTK, starting in 2010 - 12.37%, 3.32% today

At $232 a share, First Solar is trading at significant premiums, but analyst Adam Hinkley of Oppenheimer says yesterday's quarterly report "justifies its valuation premium to the group."

"We are increasing our price target to $275 from $250, which is based on an unchanged multiple of 50x our 2009 EPS estimate."

"Although this is a lofty multiple, we believe it is warranted given FSLR's flawless execution, industry cost leadership, secure backlog of fixed-price take-or-pay contracts, and expectation to grow earnings at a CAGR of ~100 percent over the next two years," he said in a note to clients this morning.