The average energy stock has a yield of around 3.6%. You can do way better than that with either Enbridge (ENB -0.96%) or Enterprise Products Partners (EPD -0.27%), which at this writing yield 6% and 6.8%, respectively. Those lofty yields, however, aren't a sign of risk. They are actually a no-brainer opportunity to add two reliable and growing income streams to your dividend portfolio.Here's what you need to know. Oil is a volatile commodityThe energy sector is known for its volatility, thanks to the commo ...