Venture capital investment in clean technology grew 10% from the second quarter to the third this year. According to a report by the Cleantech Group and Deloitte, 134 companies received investments of $1.59 billion – up from $1.2 billion in the second quarter. The sector's upward trajectory continues, with last quarter marking the second in a row of double-digit growth. In the first quarter of 2009, venture capital investment in cleantech companies hit a low of $1 billion.

The strong third quarter has made the cleantech sector the largest in the venture capital business, according to the Cleantech Group, pulling ahead of biotech. Twenty-seven percent of venture capital funds invested in the second quarter of 2009 went to cleantech companies – up from 3% at the beginning of 2004.

Tesla Motors chairman Elon Musk said at a conference recently that he plans to take the electric car maker public by the end of 2008. Without having had an opportunity to look at the financials -- there hasn't yet been a registration statement or prospectus -- I would say that this is exactly the kind of IPO that investors should avoid.

I know, it's exciting and new. It's technology. It's stuff that could change an entire industry and quite possibly the world. As Musk said, "Thirty years from now the majority of new cars will be pure electric, not hybrid."

Exactly. Just like Sirius Satellite Radio (NASDAQ: SIRI) and XM Satellite Radio (NASDAQ: XMSR). And all those internet stocks. And the hundreds of exciting new car makers a hundred years ago that captured the fancy of investors before they ended in bankruptcy.

Tesla Motors is one of the more interesting "emerging alternative energy auto" companies out there. Actually, it has a better story than most. The company's roadster rivals a Ferrari and is sold out for its current production runs in 2008. The company also plans to introduce a four-door sport sedan in 2009 or 2010.

Tesla just got extra funding as well. It completed a $40 million round of bridge financing from Valor Equity Partners and Elon Musk, its chairman. The company had already raised funding in prior rounds, and it has expressed at least some interest in coming public. Since it has VC funding, that choice might not even be entirely up to the founders. My prediction: you'll probably be able trade Tesla Motors stock as a public company within the next twelve months or so. Bridge financing is often the last round of financing before a key event (such as an IPO filing or significant final round of financing).

Investing in electric cars, for better or worse, is not so easy. I have noted here are a couple of current investment plays that traders can use for this, but even these are not exactly the easiest out there. Honda Motor Co. (NYSE: HMC) has its new fuel cell car coming to the U.S., but its geographic limitations are going to be severe at first and it will yield nothing significant in terms of percentages of its entire U.S. fleet until after 2010. There is also another tiny OTC-company called Zap! (OTCBB: ZAAP) but as with all OTC stocks you have to be extra diligent in investigating the company. Zap! has its high performance electric cars coming for some $30,000.