Now that almost all of our favorite midstream companies have reported first-quarter earnings, it's time to take a look at the group's performance as a whole. Today we'll recap a few big winners and losers, and make note of any trends that could affect your investments.

Given the current state of U.S. energy production, most midstream companies are winners these days. Kinder Morgan Energy Partners (UNKNOWN:KMP.DL) got things started off on the right foot, reporting in mid-April and beating expectations on revenue and EPS. Here are some highlights from around the industry:

  • Buckeye Partners (NYSE:BPL) trounced analyst expectations on the top and bottom lines, and recorded a distribution coverage ratio of 1.21 times payouts, allowing the partnership to boost its distribution.
  • DCP Midstream Partners' (UNKNOWN:DCP.DL) distributable cash flow popped 40% year over year, and the partnership completed its Eagle Ford dropdown transaction with parent company DCP Midstream, boosting its stake in the lucrative South Texas shale play.
  • Boardwalk Energy Partners' (NYSE:BWP) operating revenue and net income increased 5% and 10% year over year. More importantly, distributable cash flow popped 24%, though the partnership elected to hold the distribution flat quarter over quarter.
  • Energy Transfer Partners (NYSE:ETP) had no distribution increase either, but things are looking better than they have in a while. Production in the Eagle Ford Shale is driving growth at ETP, and the partnership is reorganizing into an operation that is stronger and more diverse than ever before.

Very strong results here, now let's take a look at some midstream companies that didn't perform as well.

Participation trophies
Enbridge Energy Partners and ONEOK Partners have seen better days. Enbridge Energy reported a net income loss of $67.7 million. Volumes on its liquids pipelines were flat, but low NGL prices crushed earnings. On top of that, certain crude oil systems are suffering mightily, particularly EEP's North Dakota lines, were volumes were cut in half because producers are opting to utilize rail transportation.

ONEOK Partners watched its distributable cash flow plummet more than $80 million, year over year. It too was stung by low NGL prices, as operating income in that segment fell $40 million. As you might have guessed, the effect of low NGL prices is one of our industry trends, so let's take a closer look.

Diversity is absolutely crucial in the midstream business, and Enbridge Energy Partners can testify to that. The price of natural gas liquids remains depressed, and many of these companies take possession of their NGLs at one stage or another, resulting in slumping margins that hurt the bottom line. While this trend hit different companies in different ways -- and you should know exactly how it could hurt yours -- the bigger midstream entities mitigated the loss with multiple revenue streams.

For example, Kinder Morgan got pinched by NGL prices in its CO2 segment. The company produces NGLs out in the Permian Basin, and therefore is very much on the hook for low prices. However, this segment still grew 1% year over year because production growth hit a record high, and this segment also includes the partnership's crude oil production. Plus, KMP has four other business segments that make serious contributions to its results and help mitigate the NGL pricing pain.

Again, the big, diverse companies like Kinder Morgan and Enterprise Products Partners had a much easier time compensating for these losses than Enbridge and ONEOK.

That point leads us into our next trend. Fee-based business is on the rise in the midstream industry. By securing fee-based transportation or processing contracts, midstream companies avoid commodity risk altogether, which explains why almost every midstream project coming online -- pipelines, terminals, treatment centers, fractionators, etc -- is doing so supported by fee-based agreements.

Enterprise Products Partners drove its Eagle Ford fee-based business up 38% alone in the first quarter. Management is reporting that the overall fee-based increases at Enterprise are enough to mitigate commodity risk in its other segments. Again, size and diversity are crucial here.

Plains All American is another midstream that had a very strong first-quarter, and continues to pump its cash into building up its fee-based business. Management is dedicating 99% of its capital expenditures to fee-based projects, so don't expect this trend to die down anytime soon.

Foolish takeaway
It was a very strong first quarter for the most part, and the midstream industry remains full of some excellent opportunities for investors. For the next few years, the strongest, best-run companies in this bunch are going to continue to crank out excellent results based on the surge in domestic energy production.