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.

Fool analyst Jim Mueller owns shares of Transocean. First Solar is a Motley Fool Rule Breakers recommendation. Atwood Oceanics is a Stock Advisor pick. The Fool owns shares of Transocean. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool's disclosure policyhas never considered itself messed up, at least when it's comparing itself to other disclosure policies.