This Neoclassical stone building housed the world's first generating station to produce and transmit alternating current for industrial use. It still provides power for Telluride. The noted western historian David Lavender, a Telluride native, described how locals marveled at Nunn's powerhouse in The Rockies (1968):
Every Sunday afternoon during good weather people rode by train and carriage from Telluride to see the generator start up.… Electric arcs jumped six feet when the switches were thrown. A deep-throated hum filled the tiny room, and after the display was over, some popeyed miner always asked how long it took the alternating current to rush up the hill to the Gold King, give the armature a twist, and return. By dark, maybe? When told, the questioners were invariably indignant: 186,000 miles a second? Whose leg are you trying to pull, mister?