For those readers who insist on an explanation for the ending episode of Twin Peaks, you need to follow the clues:
The white and black lodges are portals between universes, powered remotely by electricity. Cooper and Diane traveled from the universe of Twin Peaks to the universe of Lone Peak. Their sexual liaison generated 1.21 gigawatts of sexual energy that bounced Diane back to Twin Peaks and allowed Dale to drive Laura to Lone Peak on a single refill of gasoline.
As they entered Lone Peak they passed the Single R Diner, just opened for business and waiting to earn its second R from the Zagat Guide to Greasy Spoons. When they arrive at Laura’s house, the Meals on Wheels lady greets them at the door (although many dispute that they are the same person).
This causes Cooper to ask what year it is, realizing, at last, that he and Laura/Carrie have now been transported to a third universe Tri Peaks.
See how easy it is, once you know where to look?