The Eastern Seaboard
Generation, transmission and the data centers they feed. A story in 4 stops on the Wattlas map of the North American grid.
Virginia to New England
By the 1920s every city in the Northeast had its own electric company, and every one of them paid for plants that mostly sat cold, held in reserve against a breakdown. On September 27, 1927 three companies in Pennsylvania and New Jersey joined their systems in the first continuous power pool in the US, so that a plant lost in one territory could be covered from another. That pool grew into PJM, and the habit of sharing spread up and down the coast. Sharing over longer distances called for higher voltage, and after the Second World War the lines of the day began to run out of room. In Québec a Hydro-Québec engineer named Jean-Jacques Archambault wanted to bring the power of the Manicouagan far to the south, and he argued for a voltage never used anywhere in the world. To the company's decision makers 500 kV looked like the wiser and safer choice. Archambault held his ground, pointing out that one 735 kV line could do the work of four 315 kV lines, and on November 29, 1965 Premier Jean Lesage inaugurated the world's first 735 kV line, strung on 1,400 towers from Manicouagan to Boucherville, across the river from Montreal. American Electric Power was pushing toward extra-high voltage on its own path, and in 1969 AEP energized the world's first 765 kV line. Appalachian Power, one of AEP's companies, owns nine of the 765 kV lines on this map.
On the map: Plants, lines and data centers crowd the corridor from Virginia north. 765 kV is the highest AC voltage on the map, on 47 lines, with owners including Appalachian Power. Farther north, the map has 338 lines at 735 kV in Québec and Labrador.
Sources: AEP, Hydro-Québec, PJM
Data Center Alley
In the summer of 2022 the builders of Data Center Alley heard something they had never heard from their utility. Dominion Energy warned that the transmission serving eastern Loudoun County, around Ashburn, could no longer keep pace, and it paused new data center connections there. Some projects already under way might wait years for power. For a county whose farm fields near Dulles Airport had filled with windowless server halls, one campus after another, the news landed like a brake thrown at full speed. A 2024 study by JLARC, the Virginia legislature's watchdog, found Northern Virginia is the largest data center market in the world, with 13% of reported global capacity, and every one of those buildings is served inside PJM, the pool that began in 1927. Each new campus can ask for the kind of load once reserved for a steel mill or an aluminum smelter, and they were arriving in clusters. Dominion resumed connections in steps, handing out capacity as it found room on the existing wires, with the new lines and substations the area needed still years from finished. A utility that had spent a generation planning for nearly flat sales was planning for growth again, and Loudoun was where it learned how fast that growth could come.
On the map: Data centers cluster in Loudoun County, west of Washington. Virginia has 489 of the map's 2,764 existing data centers, more than any other state (Texas 274, California 155).
Sources: JLARC, Data Center Frontier, Loudoun Now
Manhattan
John Lieb was twenty-two, one of Thomas Edison's young engineers, when he stood at the main switch inside the Pearl Street station on the afternoon of September 4, 1882. On Edison's order he closed it, and current from the station's Jumbo dynamos, steam-driven machines so big they were named after P. T. Barnum's elephant, ran out through copper mains that Edison's crews had spent months burying beneath a few blocks of Lower Manhattan around Wall Street. Lamps came on in offices along the route, and New York had an electric utility, a company selling light from one station to the customers on its wires. IEEE's Power & Energy Magazine calls it the world's first permanent central generating station. The copper under those streets set the pattern for everything that followed on the island. As the city filled with elevators, subways and skyscrapers, the wires stayed underground, and New York grew one of the largest underground electric systems anywhere, a web of cables and vaults that began with a single switch and a young engineer waiting for his cue.
On the map: Substations and lines crowd into New York City; the big plants sit along the East River and across the Hudson in New Jersey.
Sources: Wikipedia, IEEE Power & Energy Magazine
The Northeast at night
More than 800,000 New Yorkers were riding the subway on the evening of November 9, 1965 when the trains stopped dead in their tunnels. Those who climbed out found a full moon over a city with its lights out. The failure had begun at 5:16 pm near Niagara Falls, where a relay set too low tripped a line out of Ontario's Sir Adam Beck 2 station, and the collapse ran through Ontario and on into the Northeast in a matter of minutes. About 30 million people lost power, some of them for as long as 13 hours. In 1968 the utilities created the National Electric Reliability Council, the forerunner of NERC, though its rules held only as long as each company chose to follow them. New York went dark again on August 14, 2003. Just after 4:10 pm a cascade that had begun in Ohio, where heavily loaded lines sagged into overgrown trees, swept into the city. Office workers poured out of Midtown and walked home across the bridges, and firefighters spent the evening freeing people from stalled elevators in about 800 Manhattan buildings. Con Edison crews worked through the night. Parts of Manhattan had power back around 5 am, and the whole city by August 16. In all the blackout reached 50 million people, and this time Congress acted, with a 2005 law that made reliability standards enforceable.
On the map: Satellite city lights under the grid: the lines run where the lights are.
Sources: US-Canada task force (1965), US-Canada task force (2003), 16 U.S.C. 824o, Wikipedia (1965 blackout), Wikipedia (2003 blackout)