Yesterday, the US Senate voted Tuesday to extend solar tax credits for the next eight years. The news is positive for the following alternative energy stocks, I have covered here: PWER, NX, and ATA.TO.

Despite significant exposure to the US residential real estate market, I believe that Quanex (NYSE: NX), a recent spin-off, has solid appreciation potential over the next few years. My optimism is based on the following two factors: the company’s growing presence in the thin film solar market, and a pristine balance sheet ($50 million in net cash, $2 million in debt, and $20 million in cash pending receipt), which should allow NX to pursue highly accretive acquisitions in the current weak operating environment. In addition, the stock’s low valuation, already appears to reflect the well-known problems in US residential real estate. As such, a slight sentiment change in the macro environment, combined with a growing recognition of NX’s solar and other green growth opportunities, could lift the shares.

Like many stocks in recent weeks, Lufkin (LUFK) has sure been a roller coaster. After recommending the stock back in July at about $78, the stock soared after an exceptional earnings report, only to completely collapse over the last week or so in the broader oil/commodity sell-off. Given sharp share price drop, I thought it might pay to take a step back and run an earnings stress test on LUFK assuming oil prices continue to decline dramatically. Interesting, this type of stress test can be done for many other oilfield service shares, in order to determine potential downside in the event that oil prices do not stabilize (an unlikely scenario in my opinion).

With the stock market in another big swoon, I thought it would pay to review one classic method of making money in stocks. Hopefully, this post will help us fight the emotion of fear which grips all investors during major corrections, of which we’ve had tons in the last year or so.

Power-One Inc. (Nasdaq: PWER – Current Price: 2.10) could potentially rise 50% to 100% over the next twelve months, as financial results, driven by the company’s fast-growing solar and winder inverter business, begin to show significant improvement. In addition, a recent acquisition of a competitor to PWER by Schneider Electric , a huge European conglomerate, provides a solid metric for estimating the potential takeout value of PWER under various scenarios.

Since financial markets are incredibly efficient and since I cannot bring myself to fully research investment opportunities unless I have some real financial commitment, I’ve always subscribed to Soros’s maxim of: Invest First and Investigate Later. This strategy, though, can sometimes backfire, as is the case with UTSI.

Even though my gut instincts prove correct in many instances, in certain cases, such as that of UTSI, my intuition is misguided. In this post, I’ll highlight some additional information that I’ve recently uncovered that show that UTSI, though still an interesting speculation, is not nearly as cheap as my initial thesis implied.

Even though the company is still losing money, UTSI seems like a good buy here, as the stock price appears to assign a negative value to the company’s current remaining business, which throws off over $700 million in annual sales.

SolarFun (SOLF), a Chinese manufacturer of polysilicon-based solar modules, recently announced financial results, which were greeted negatively by the market, but which were actually positive in certain respects. Specifically, the company’s detailed breakdown of capital outlays into cap-ex and pre-payments to suppliers, provide a more accurate measure of the company’s true profitability, and give some indication of future financing needs and cash-flow potential of SOLF. In addition, the deal with Q-Cells and the company’s gross margin projections for 2009, both signal interesting possibilities over the next year. Combined, the above factors can provide certain guidelines of how to speculate, and hopefully make money, in SOLF’s stock going forward.

In this post, I’ll take a closer look at Gafisa (NYSE: GFA BP: GFASA3.SA), a Brazilian homebuilder which I mentioned in a previous post. What’s interesting about Gafisa is that the company appears almost impossible to value, and yet it still attracts significant interest, both from Brazilian and foreign investors. Though it’s a difficult task, I’ll attempt to provide a general, and yet still very simplified, framework for an evaluation of Gafisa. My basic assumption, given the growing momentum of mortgage securitization in Brazil, is that the best way for an outside investor to value the company, is perhaps to assign some value to the company’s growing receivable balance, while taking into consideration outstanding debt obligations.

A good way to play a bounce in the Brazilian stock market (down over 30% in a few months) is via real estate shares.