One popular way to capitalize on America's growing energy production is the master limited partnership. These investments typically offer higher yields than corporations. While MLP taxes are a hassle, the returns are usually worth it. Energy midstream MLPs are one of my favorite investments, but they are hardly foolproof. Below are two MLPs worth your attention and one that you might want to avoid.

Diversified midstream MLP
For businesses as well as portfolios, owning a diversity of assets is a smart move. Energy Transfer Equity (NYSE:ET), for example, holds stakes in four different MLPs with another company set to join later this calendar year. These different MLPs include Energy Transfer Partners, Sunoco Logistics, Regency Energy Partners, and Trunkline LNG. Each individual company provides midstream services. Trunkline, not surprisingly, handles liquefied natural gas. The others handle natural gas, crude oil, and natural gas liquids.

You can invest in these MLPs individually, but take a good look at the parent, Energy Transfer Equity. Its diversity helps insulate it from the price swings of any one commodity. Since the fourth quarter of 2012, when the merger with Sunoco was finalized, revenue and distributions have been steadily climbing. The distribution has increased a penny a unit per quarter -- not electrifying, but at least it's growing. Units climbing 83% in the past year is another story.

Looking forward, Energy Transfer Equity stands to gain from a variety of sources. The addition of Trunkline in late 2013 positions the company to export natural gas. Approval from the federal government for Trunkline exports should come in 2015. Actual exports hopefully will begin in 2019. A 15-year deal to export natural gas to Mexico by pipeline was recently signed. Lastly, Energy Transfer announced its intention to acquire Susser Holdings, a gasoline and convenience store operator located primarily in Texas.

Growing distributions
While small in market capitalization, Genesis Energy (NYSE:GEL) offers investors a track record of growing distributions and capital gains. Specifically, Genesis boasts 35 consecutive quarters of increased distributions. The current yield is roughly 3.9%. The distribution coverage ratio has been at least 1 for the past two years. The stock has also steadily increased in price, almost doubling in the past two years and more than tripling over the past five.

Genesis operates pipelines, rail cars, trucks, and barges all to transport crude oil and refined products from the field to the refinery and beyond. Additionally, Genesis provides carbon dioxide to drillers for enhanced oil recovery operations. Lastly, Genesis provides refiners with a proprietary sulfur-removal process with the resultant sodium hydrosulfide taken as payment in kind. The sodium hydrosulfide is then sold to a variety of companies, primarily in the mining and pulp and paper industries.

Several expansion projects should come online for Genesis this year. For example, a joint-venture offshore pipeline in the Gulf of Mexico should soon be operational. Multiple rail car facilities were recently upgraded and expanded in Louisiana, Texas, and Florida. Lastly, Genesis' operations in the Pronghorn play in Wyoming have opened new rail, pipeline, and truck facilities with more on the way. All these projects should add to Genesis' distributions by year-end 2014.

Having troubles
While transporting natural gas and natural gas liquids has paid off for other midstream companies, Boardwalk Pipeline Partners (NYSE:BWP) has had its difficulties. In the fourth quarter of 2013, the company paid a distribution of $0.53 per unit. The next quarter, the distribution dropped to $0.10. This decision was made to give Boardwalk more cash to invest in the business. Some see this move as an attempt to keep the partnership alive. Given the relatively flat performance of the stock over the past two years, not to mention relatively flat revenue, earnings, and distributions, that "keep the partnership alive" theory has some merit.

Things didn't exactly improve when Boardwalk's partner, Williams Companies, halted its investment in the Bluegrass natural gas pipeline in April. Both companies are reviewing their options, and Boardwalk's CEO Stanley Horton insists the project is not dead.Still, it's not good news. On the other hand, Boardwalk's latest earnings report beat expectations on both revenue and earnings.

So what's going wrong? Contract renewals and revenue are hurting. So what's Boardwalk doing about it, particularly with the cash it's not paying out in distributions? During its latest investor presentation, Boardwalk outlined various projects to attract or serve new customers. Some of these projects will be completed this year, while others will have completion dates in 2016 or later. Prospective customers include utilities and natural gas exporters.

Final Foolish thoughts
Investing in Boardwalk is investing in a turnaround story. For my risk tolerance, I'd steer clear until more evidence of a turnaround emerges. While I'm bullish on Genesis, I am taking a hard look at Energy Transfer. There is safety in its size, business diversity, and growing revenue and distributions.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.