What You Need To Know About MLPs And Investing In Energy. As many investors have been considering adding, or increasing, allocations to the energy sector in 2014, energy-oriented master limited partnerships (MLPs) have garnered a lot of attention. While MLPs are not a new investment vehicle (in fact the first MLPâApache Oil Companyâwas launched in 1981), they do represent a different type of investment to many investors and financial advisors.