Energy Conversion Devices (NASDAQ:ENER) is green, and I don't just mean in a tree-hugging sense.

Aside from supplying the solar market with a flexible thin-film product, ECD's stock price is actually up on a trailing-12-month basis. First Solar (NASDAQ:FSLR) can't make such a claim. Nor can SunPower (NASDAQ:SPWRA) (NASDAQ:SPWRB). As for Rule Breakers pick Suntech Power (NYSE:STP) -- let's not even go there.

This company has traveled a long, long road to prosperity. Much like Evergreen Solar (NASDAQ:ESLR), ECD came public at a very early stage, and has tested the patience of early investors. Equally frustrating is that just as the firm hit its stride, the global economy began seizing up.

Customer credit availability is one of the key issues weighing on solar suppliers, and ECD is not immune. June fiscal year revenue guidance has been cut from the $455 million to $485 million range cited in November to a more subdued range in the low $400's. ECD also sells non-solar products, but solar accounts for nearly all of the firm's revenue.

Last summer, I mentioned being impressed with ECD's cash-flow-positive operations, considering the limited scale of operations. As output has ramped up (quarterly shipments nearly doubled compared to last year), so has the cash generation. Net operating cash flow topped $37 million over the past six months.

Of course, free cash flow is another matter. ECD has a relatively attractive manufacturing operation achieving strong gross margins, but a lot of capital investment is still required. Over $100 million was invested over the same trailing-six-month period, and $70 million of additional commitments remained the end of the calendar year. That's just about exactly the amount by which cash on hand exceeds long-term debt, so ECD is in fairly good financial shape.

ECD is rated a middling three stars by Motley Fool CAPS participants. Think this firm will shine in '09? Cast your own vote right here.

Fool contributor Toby Shute is active in CAPS under the moniker TMFSmashy, but he doesn't have a position in any company mentioned. The Motley Fool has a disclosure policy.