The boom in oil and gas production across the United States has our energy pipelines bursting at the seams (figuratively, although literally on the rare occasion), and that is at today's production levels. With natural gas and oil production expected to grow for the next several years, it will require huge investments in pipelines to make it possible -- $642 billion, to be precise. For investors, there are three companies that are in a great position to build out that infrastructure: Kinder Morgan Energy Partners (UNKNOWN:KMP.DL), Energy Transfer Partners (NYSE:ETP), and Spectra Energy (NYSE:SE)

The reason these three companies stand out among the rest is because of one crucial element regarding master limited partnerships: Their industry-leading weighted average cost of capital. Find out why this metric is so important for MLPs looking to take on this massive infrastructure and why it makes them compelling investments.