Oil may be on its way back down, but there are still opportunities in the energy space, portfolio manger Matt Sallee told CNBC Thursday.

"We see some good opportunities in energy right now. Frankly, I think the price is unsustainably low for crude oil, so we are advising investors to make long-term investment decisions, and over the long-term, say you have a year plus time horizon, we think it is a good time to buy energy stocks," the Tortoise Capital Advisors managing director said in an interview with CNBC's "Power Lunch."

Tortoise Capital Advisors manages over $17 billion, all in energy funds. Right now, they're seeing strength in the refineries, petrochemicals and the pipeline businesses.

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"We're looking for pipeline investments in the MLP space—there's a lot of winners in this sector," Sallee said.

"You think about a company like Magellan Midstream Partners. They have the largest refined product network in the country, they are benefiting from lower fuel prices which are driving increased demand. Very solid balance sheet, good dividend coverage—we think they'll grow their dividend about 15 percent this year, so a real high-quality company that we see good long-term total returns in."

"We do like the refiners, specifically Phillips and Valero. We think that they are not pricing in current spreads, so we see upside in these stocks. Again, they're benefiting from lower crude prices and higher demand. The gasoline prices are being set off Brent crude, so to the extent that our WTI or domestic stay discounted relative to global prices, that's a big advantage to these guys."