Yards Creek is a 450-megawatt pumped storage operation in the Appalachian Mountains in northwestern New Jersey, which went online in 1965. It has an upper and lower reservoir separated by 3,600 horizontal feet, and 700 feet in elevation. An 18-foot diameter pipe carrying the water up and down slope emerges from underground halfway down the hillside, and splits into three penstocks that connect to three pump/turbines in the plant. Water is pumped up for storage at night, and flows down during the day to produce electricity for the grid.