The way some market commentators are talking these days, you'd think that all energy stocks were doomed. Yet for the midstream MLP sector this couldn't be further from the truth. In fact some MLPs, such as MPLX (NYSE:MPLX), are growing like gangbusters and bringing dividend investors along for the ride. 

Here's how MPLX plans to grow its distribution -- a kind of tax-deferred dividend -- at over 20% annually even if oil prices remain low for several years. 

The secret to sustainable and growing distribution: a tollbooth business model
To be able to not only sustain its generous yield -- 4.1% compared to the S&P 500's 2.1% -- but also grow it in the face of the lowest energy prices since the financial crisis, it's vital that a company's business be designed to generate recurring, stable, and highly predictable cash flow. 

This is the hallmark of MPLX's business model, which has long-term fee-based contracts securing a tollbooth-like stream of income with minimal commodity exposure. 

Mplx Assets

Source: MPLX investor presentation.

As this asset map shows, MPLX's pipelines services refineries owned by Marathon Petroleum Corporation (NYSE:MPC), which also acts as MPLX's sponsor, general partner, and manager. This not only creates a symbiotic relationship in which Marathon Petroleum -- one of America's largest independent refiners -- provides MPLX with an ongoing source of strong demand for its transportation infrastructure, but it's also a massive source of growth.

Mplx Organizational Chart

Source: MPLX investor presentation.

That's because, as this chart shows, Marathon Petroleum owns a combined 71.5% limited/general partner interest in MPLX, in addition to its incentive distribution rights, or IDRs. These IDRs entitle Marathon to 50% of all quarterly distributions above $0.39375 per unit per quarter, and when combined with the company's enormous equity stake in the MLP, that means it has an enormous financial incentive to grow MPLX's distribution as quickly as possible. 

That's one of the reasons MPLX's management is aiming for distribution growth of 29% in 2015, 25% in 2016 and 2017, and 20% in 2018 and 2019, respectively. However, just because MPLX is planning on some impressive payout growth doesn't mean it's being irresponsible when it comes to the safety of the distribution. 

For example, just look at its historic distribution coverage ratio, or DCR, and how on a 12-month basis the MLP has always been able to support its payout with its distributable cash flow, or DCF, with ample room to spare, despite growing the distribution at a 23% compound annual basis during this time. 

Mplx Dcr

Source: MPLX investor presentation.

Marathon will continue dropdowns 
OK, so now we understand how MPLX can sustain a generous payout during an oil crash and why Marathon Petroleum is so gung ho to grow its payout quickly, but how exactly is it going to do that? Midstream MLPs have three main ways of growing: dropdown acquisitions, third-party mergers, and organic growth projects. MPLX is planning on growing through all of these. 

Marathon Petroleum has been dropping down midstream assets to MPLX since its IPO and still has a substantial amount of assets it plans to sell to its MLP to help it grow. 

Marathon Petroleums Mlp Assets

Source: MPLX investor presentation.

However, the biggest long-term boost to MPLX's growth may come from Marathon's $16 billion merger of MarkWest Energy Partners (NYSE:MWE), the largest gas gathering and processing service provider in the booming Marcellus and Utica shale, with MPLX.

MarkWest Energy Partners will become an independent subsidiary of MPLX and a strong source of organic growth projects, such as the recently announced $1 billion investment in a 2 billion-cubic-foot-per-day natural gas-gathering system in the Utica shale. According to MarkWest Chairman, President, and CEO Frank Semple, this organic growth project is just the tip of a $6 billion to $9 billion investment iceberg that the merger with MPLX will allow. 

Takeaway: MPLX's long-term growth strategy is poised to enrich dividend investors 
One of the best things long-term income investors can do is remember that Wall Street commentators aren't interested in the same things you are. Analysts care about quarterly and annual results and short-term price movements and thus can become obsessed with things like oil crashes and give terrible advice that might have investors selling near a market bottom. 

A much better strategy is to focus on the long-term business model of strong energy operators such as MLPX. With its large and well-financed sponsor, enormous backlog of future dropdowns, and superb distribution growth potential, this fast-growing MLP is likely to make a winning long-term energy investment, even if oil prices remain low for several years. In fact, a decreased unit price resulting from the oil crash may end up creating a superb buying opportunity that helps boost returns for MPLX investors who buy today. 

Adam Galas has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. 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 has a disclosure policy.