This article is part of our Rising Star Portfolios series.

It might have been Peter Lynch who said it, but investing involves turning over a lot of rocks. And for a portfolio that looks for situations where the market's expectations are too pessimistic, that means looking at a lot of companies.

Last week, I picked Transocean (NYSE: RIG) as the first stock in my Messed-Up Expectations (MUE) portfolio. At prices in the low $60s, the market is expecting very little growth in free cash flow (FCF) over the next several years. So, might there be other opportunities in the energy sector?

Looking around, I turned down Atwood Oceanics (NYSE: ATW), another offshore driller, and SunPower (Nasdaq: SPWRA). The former because the market is expecting nearly 30% growth in FCF per year for five years when it's only done barely 7% per year for the past three, and the latter because it's been FCF-negative for the past eight years, as well as the trailing 12 months.

First Solar (Nasdaq: FSLR) was also a non-starter as a MUE candidate. At 33% expected growth in FCF for five years, I think that's a bit much for a company without a consistent history of positive free cash flow.

But the energy sector is not totally devoid of possibilities. One that caught my eye was Power-One (Nasdaq: PWER), a maker of converters for connecting the DC output of solar and wind farms to power grids, which use AC. It's rapidly moved from No. 9 to No. 2 in market share and just reported a very nice quarter. As for messed-up expectations, at current prices, the market's expecting less than 6% annual growth in FCF, while it's actually been growing that much more rapidly over the past several quarters. A bit risky, maybe, as it doesn't have a long history of positive free cash flow, but intriguing nonetheless.

Before purchasing, of course, more due diligence is needed. One thing I am still figuring out is the way the company views itself going forward. Is it now a solar and wind energy play, or does its legacy tech business still have legs?

Add Power-One to your watchlist and then come join the discussion on this company and others hiding under rocks, over at my Rising Star Portfolio discussion board.