The Tehachapi Mountains in central California's Kern County are a wind energy museum. Four generations of turbines are distinguishable on their slopes and ridges, with an installed capacity of more than 800 megawatts of wind power. These hills are alive with the sound of wind power. Kern was once known as oil country and its rich fields supplied much of the oil that made California the oil capital of the U.S back in the 1920s and fueled the U.S. industry's mid-20th century boom. As Ed Duggan of wind developer Oak Creek Energy said, "Kern County knows energy."