History of the grid
From Pearl Street to Data Center Alley, twenty-three places where the grid changed shape. A story in 23 stops on the Wattlas map of the North American grid.
Act I · 1882–1896
Pearl Street Station (1882)
On the afternoon of Monday, September 4, 1882, Thomas Edison was at the Wall Street offices of his backer, J. P. Morgan, waiting for the lamps to come on. A few blocks away, in a pair of old buildings on Pearl Street, the first of the station's six dynamos of about 100 kW began pushing 110 V direct current through copper mains buried under the streets of the First District, a quarter of a square mile of Lower Manhattan. About 85 customers and some 400 lamps lit up that first day. Until then electric light had been a rich man's luxury, made by a private generator in his own basement. Edison meant to sell it the way the gas companies sold gas, from one central plant to anyone on the line willing to pay, and Pearl Street was his first permanent central station. It became the prototype for central-station electric utility systems, and hundreds of Edison systems were modeled on it. A fire on January 2, 1890 damaged the station, and it was retired and dismantled in 1895, by which time central stations were lighting cities across the country and the business Edison had begun on Pearl Street no longer needed the building.
On the map: The map marks Edison's Pearl Street Station in Lower Manhattan as a historic grid site dated 1882, one of 301 on the map. Around the dot are the substations and lines of today's grid; the next four stops follow the fight between direct and alternating current.
Sources: IEEE Milestone: Pearl Street Station, 1882, IEEE Power & Energy Magazine, Wikipedia
Great Barrington, 1886
Edison's system had a limit built into it. Direct current at 110 V lost so much of itself in the copper that a station could reach only customers within a mile or so, and there was no cure, because direct current could not be stepped up or down by transformers. Alternating current could. In the Berkshire town of Great Barrington, Massachusetts, a Westinghouse engineer named William Stanley set out to show what that meant. He put a Siemens alternator in an old rubber mill and ran it at 500 V. A transformer raised the voltage to 3,000 V for the run along Main Street, and six more, tucked into basements, brought it back down to 100 V. On March 20, 1886 he lit Main Street with it, twenty businesses in all. On one street he had built the modern grid in miniature, with high voltage for the journey and low voltage at the door, and the IEEE calls it the first practical AC system with transformers, virtually identical to how power is distributed today.
On the map: The dot is placed at Stanley Park in Great Barrington, Massachusetts, where the plaque stands; no source gives the exact spot of the 1886 plant or its circuit, and the site's own note says so. The map lists it as a demonstration, dated 1886, among its 301 historic sites.
Sources: IEEE Milestone: Alternating Current Electrification, 1886, Wikipedia
Willamette Falls to Portland (1889–1890)
At Oregon City the Willamette River pours over a horseshoe of basalt, and in the 1880s all that falling water sat far from the city that wanted its power. In 1889 the Willamette Falls Electric Company closed the gap. It sent direct current fourteen miles down the river to Portland's streetlights, what PGE calls the nation's first long-distance transmission of electricity. For the first time the plant could stand where the energy was, at the falls, miles from the lamps it lit. Generation at the resource and wires to the city would become the pattern for a century of dams, coal plants at the mine mouth and, much later, wind farms on the plains. In 1890 the company sent alternating current along the same route. PGE's T. W. Sullivan plant, built at the falls in 1895, still runs.
On the map: The hydro plant at Willamette Falls is listed as Sullivan on the map: 18.3 MW in Oregon, operated by Portland General Electric Co, with 1924 as its year. No plant on the map carries the Willamette Falls name.
Sources: Oregon History Project, PGE, Wikipedia
Ames (1891)
High in the San Juan Mountains above Telluride, the Gold King mine was being eaten alive by its fuel bill. Coal for its steam engines came up the mountain by mule, and one of the men behind the mine, a lawyer and banker named L. L. Nunn, went looking for something cheaper. He found it in the water rushing down the valley at Ames, and in a bet on Westinghouse's new alternating current. From June 19, 1891 a 100 hp Westinghouse alternator in a small plant beside the river sent single-phase AC at 3,000 V and 133 Hz 2.6 miles up the mountain to the Gold King's mill. It kept running through mountain winters and lightning storms, and a 1905 powerhouse on the same site is in service today. Ames was one of the first plants anywhere to generate AC for industrial use. It gave anyone weighing how to tame Niagara Falls proof, from a mining camp high in the Rockies, that the new current could do real work, and it became a significant precedent for the much larger plants built there.
On the map: Ames Hydro, in the mountains southwest of Telluride, Colorado, is 2.8 MW on the map: a hydro plant operated by Public Service Co of Colorado, with 1906 as its year.
Sources: IEEE Milestone: Ames Hydroelectric Generating Plant, 1891, Wikipedia, IEEE Power & Energy Magazine
Niagara: the Adams plant decides it (1895–1896)
Niagara Falls was the prize. More power poured over its edge than any city of the age could use, and the question of how to harness it drew in a commission of the world's leading engineers, chaired by Lord Kelvin, who at first favored direct current. In the end Niagara's builders chose polyphase alternating current, the system built on Nikola Tesla's patents, and gave the generator contract to Westinghouse. The Adams plant started in August 1895 with Westinghouse 5,000 hp, 25 Hz generators, giants for their day, and in the IEEE's words the plant was a key victory for AC over DC. Just after midnight on November 16, 1896, power from the falls reached Buffalo over a 26-mile line, and the city's streetcars began running on Niagara. With that the long argument between the two currents was effectively settled, and almost every power system built since, on this continent and most others, has been an alternating current system at its core. The Adams plant closed in 1961.
On the map: The map marks the Adams Power Plant transformer house at Niagara Falls, New York, a historic grid site dated 1895. Downstream it draws Robert Moses Niagara at 2,435 MW on the New York side and, in Ontario, Sir Adam Beck 1 and 2 at 450 and 1,499 MW.
Sources: IEEE Milestone: Adams Hydroelectric Generating Plant, 1895, Wikipedia, Buffalo Architecture and History, Electrical Review, November 18, 1896 (transcription)
Act II · 1898–1970
Insull, Fisk Street and the state commissions (1898–1907)
Samuel Insull came to America at twenty-one to be Thomas Edison's private secretary, and he learned the electric business at the inventor's elbow. By the 1890s he was running Chicago Edison, and he had worked out where the industry had to go. Power was cheapest when one company built very large plants and kept them busy around the clock, selling to factories by day and homes by night, and that meant a monopoly. On June 7, 1898 he did something few businessmen would, telling the National Electric Light Association that exclusive franchises should come with public control of rates. Fisk Street opened on the South Branch of the Chicago River in 1903 with the world's most powerful steam turbine, 5,000 kW, a single spinning machine doing the work of rooms full of piston engines. The turbine was so much more efficient that its owner shut five smaller stations, and the steam turbine became the industry's standard. The regulators Insull had asked for arrived soon after. In 1907 Wisconsin and New York put utilities under state commissions, and by 1915, 33 states had them, turning the bargain he had described in 1898 into the way American power was run.
On the map: The map marks Fisk Street Station, on the South Branch of the Chicago River, as a historic grid site dated 1903. EIA still lists a Fisk Street plant at the point: 197 MW of oil-fired turbines with 1968 as its year, operated by Midwest Generations EME LLC and listed as operating.
Sources: Energy Law Journal, 1996, MasterResource, Library of Congress, HAER IL-105, Wisconsin Legislative Council, New York State Archives
PJM: Siegfried (1927)
Every city now had its utility, and every utility had to keep spare plants of its own, idle and expensive, for the day a big unit failed. Three neighbors in the East decided they could do better together. On September 27, 1927, Philadelphia Electric, PP&L and PSE&G tied their systems into the Pennsylvania-New Jersey Interconnection, the first continuous power pool in the US. They would run their plants as one fleet, sharing capacity so that each needed smaller reserves and paid less, and so that a failure at one plant could be covered by the others. By 1928 their 220,000-volt trunk lines ran in a ring of about 210 miles, with switching stations at Siegfried, Roseland and Plymouth Meeting. Other regions copied the idea, and pooling spread across the country. That ring grew into today's PJM, whose grid serves more than 67 million people in 13 states and Washington, DC.
On the map: SIEGFRIED, the substation at the center, is one entry in the map's index: 230 kV, in eastern Pennsylvania, with PJM as its balancing authority. It sits inside the PJM outline the map draws.
Sources: PJM Inside Lines, PJM history, Wikipedia, Library of Congress, HAER NJ-149, PJM, Who we are
1935: PUHCA and the Federal Power Act
The same decades that built the pools also built empires on paper. Holding companies stacked one on top of another bought up local utilities across dozens of states, and when the Depression hit, some of the tallest fell. Insull's own collapsed in 1932 and took the savings of hundreds of thousands of small investors with it. Congress concluded that holding companies spread over many states were beyond any state's effective control, and on August 26, 1935 Franklin Roosevelt, who had campaigned against the holding companies, signed the Public Utility Act. The law had two titles. The first, PUHCA, confined each holding company to one integrated system under the SEC. The second, the Federal Power Act, put interstate transmission and wholesale sales under the FPC and left other sales to the states. That line between federal and state authority still holds under FERC, the FPC's successor since 1977, and much of the rest of this story is fought along it. Breaking up the giants took years, and Commonwealth & Southern, one of the largest, gave way to Southern Company only in 1949.
On the map: The map marks the Public Utility Act of 1935 at the White House in Washington, DC, as a historic event dated 1935, one of 301 historic grid sites on the map. Its point is placed at the building, not at a sourced spot, and the site's own note says so.
Sources: Statutes at Large, 49 Stat. 803 (govinfo), 16 U.S.C. 824 (Cornell LII), Wikipedia: PUHCA, Wikipedia: Southern Company, Encyclopedia of Alabama, 42 U.S.C. 7172 (Cornell LII)
TVA and the REA: Norris Dam (1933–1936)
In the mid-1930s a farm family in the Tennessee Valley lived by kerosene lamp and hand pump while the power lines ran past to the towns. Nine in ten rural homes had no electric service, because private utilities could not make wire strung between scattered farms pay. The New Deal set out to change that with public power. President Roosevelt had signed the TVA Act on May 18, 1933, and the Tennessee Valley Authority began damming a river system that had flooded the valley for generations, and selling the power. Norris, the first dam TVA built, closed its gates on March 4, 1936. Beyond the valley the push came through Washington's purse. The REA came by executive order on May 11, 1935, and the Rural Electrification Act followed on May 20, 1936. Farmers organized cooperatives and took the loans investor-owned utilities would not, then set the poles across their own fields. By 1953 more than 90% of US farms had electricity, and across the countryside the kerosene lamp went into the cupboard for good.
On the map: Norris Dam is a 127 MW hydro plant in Tennessee on the map, operated by the Tennessee Valley Authority, with 1936 as its year. Tennessee holds 28 hydro plants, about 2.6 GW, 20 of them TVA's. Of the 83 service territories the map tags to Tennessee, 61 are municipal utilities, 21 cooperatives and 1 investor-owned.
Sources: National Archives, Wikipedia: Norris Dam, NRECA, Wikipedia: Rural Electrification Act
Hoover and the 287 kV line (1936)
The tallest dam in the world stood in a desert canyon, far from anyone who needed its power. Hoover Dam's electricity was meant for Los Angeles, 266 miles away across the Mojave, and getting it there took a line unlike any built before. LADWP's Boulder line was, at 287.5 kV, then the world's highest-voltage transmission line, carried on steel towers marching across the sand, and several of its 287.5 kV segments carry power to this day. At 7:36 pm on October 9, 1936, Elizabeth Scattergood, daughter of the city's chief electrical engineer, pressed a key, and the first Hoover Dam power started west. Los Angeles celebrated under the new light that night. Reclamation's first generator, N-2, went into full operation on October 26. Through the war the line fed the aircraft plants and shipyards of Southern California, and after it the suburbs that spread across the basin.
On the map: The map lists Hoover Dam twice, a Nevada entry and an Arizona entry of about 1,039 and 1,040 MW at one point, both dated 1936. Far to the west, east of Los Angeles, it draws two LADWP lines at 287 kV in California, about 135 km each; 24 lines on the map carry that voltage. The view is fitted from the dam to the coast.
Sources: LADWP, Reclamation, Library of Congress, HAER NV-27-M
Shippingport (1957)
Atomic energy had been born in war, and by the 1950s the government wanted it to light homes. Under President Eisenhower's Atoms for Peace, Admiral Hyman Rickover's naval reactor team built a power station on the Ohio River below Pittsburgh around a reactor first designed to drive an aircraft carrier. At 4:30 am on December 2, 1957 Shippingport reached criticality, the first large-scale central-station nuclear plant in the US. By 7:00 am on December 18 it was sending 12 MW to Duquesne Light, and on December 23 it reached its 60 MW capacity. Small as it was beside the plants that followed, Shippingport proved that a nuclear station could run on a utility network, and it held the first school for civilian reactor operators, where a generation of the industry's people learned their trade. It ran until October 1982 and was decommissioned by 1989.
On the map: The map marks Shippingport Atomic Power Station, on the Ohio River northwest of Pittsburgh, as a historic grid site dated 1957. Beside it EIA lists Beaver Valley, still running: 1,808 MW of nuclear capacity with 1976 as its year, one of four Pennsylvania nuclear plants the map lists with status operating.
Sources: Library of Congress, HAER PA-81, Pennsylvania State Archives, MG-508, Wikipedia
The 1965 blackout and NERC (1965–1968)
By the 1960s the pools had grown into webs that spanned states and crossed into Canada, and the ties that let neighbors help each other could also pass trouble along. At 5:16 pm on November 9, 1965, in the evening rush, a backup relay on a line out of Sir Adam Beck 2 near Niagara tripped. It had been set below the load the line was carrying that night. The power shifted onto the remaining lines, they tripped in turn, and within minutes the cascade had swept across Ontario and the Northeast. Over 30 million people were left without power, some for up to 13 hours. Commuters were trapped in the subway under Manhattan, and a bright moon rose over the darkened city. The industry answered by policing itself, and in 1968 it formed the National Electric Reliability Council, a predecessor of today's NERC, to set standards for the bulk power system. Those standards stayed voluntary for almost forty years.
On the map: The shaded area is the map's approximate extent of the Northeast blackout of November 9, 1965: Ontario, New York, Vermont, New Hampshire, Massachusetts, Connecticut, Rhode Island and New Jersey, each drawn whole, which overstates all of them. The ring is Sir Adam Beck 2 in Ontario, 1,499 MW on the map.
Sources: US-Canada task force report (2004), Wikipedia, Baker Institute, Rice University, Troutman Pepper
The Pacific DC Intertie: DC comes back (1970)
Direct current, beaten at Niagara, came back seventy-five years later for the job it does best. The Columbia River dams in the Northwest made more power in spring than the region could use, while California's demand kept climbing, and between them lay 846 miles. Over that distance a high-voltage DC line lost less energy than an AC one. Operators could also set its flow and hold it there, and it would not pass a disturbance from one system to the next. The line was authorized in 1964, and the blackout of the following year soon showed how much that was worth. It ran from BPA's Celilo converter station near The Dalles to the Sylmar station north of Los Angeles, and it was operating in 1970 at ±400 kV and 1,440 MW, then the longest of its kind in the world. Working alongside the Pacific Intertie's AC lines, it lets the Northwest send its spring and early-summer hydro surplus south to California. Its voltage was later raised to ±500 kV, and its capacity has been raised since.
On the map: The map records the Intertie as one Bonneville Power Administration DC line at 500 kV, about 1,360 km through Oregon, Nevada and California, from CELILO in Oregon, listed at 500 kV, to SYLMAR EAST. SYLMAR EAST and SYLMAR WEST, at its far end in California, are listed at 230 kV.
Sources: BPA, Hitachi Energy, Wikipedia, Northwest Power and Conservation Council
Act III · 1976–present
The Midnight Connection (1976)
Late on the night of May 4, 1976, likely around midnight, West Texas Utilities closed a connection at a substation in Vernon, Texas, and power began to flow north across the Red River to Altus, Oklahoma. For decades the utilities of Texas had kept their grid inside the state so that, under the line Congress drew in 1935, no federal regulator could reach it. By crossing the river on purpose, West Texas Utilities set out to force a legal confrontation over federal jurisdiction. Other Texas utilities began disconnecting from it. A year later the PUC ordered the link cut, and a federal court ruled on the dispute in 1979. FERC later determined that DC ties, which pass power between grids without locking them into step, would keep the Texas grid outside federal regulation. It is still a separate grid, though FERC has overseen its reliability since 2005.
On the map: The map marks the Midnight Connection at Vernon, Texas as a historic grid site dated 1976, placed at the town: the sources name a substation in Vernon, not which one, and the site's own note says so. The map outlines four interconnections, ERCOT among them. No DC line on the map touches Texas: ERCOT's four DC ties are converter stations, not lines.
Sources: KUT, Baker Institute, Rice University, ERCOT DC ties, 16 U.S.C. 824o (Cornell LII)
PURPA and Three Mile Island (1978–1979)
The oil embargo of 1973 left Americans in gas lines and utilities paying four times as much for fuel oil, and the country went looking for power that did not depend on it. One answer was to let someone besides the utility make electricity. PURPA, signed November 9, 1978, made utilities buy from qualifying cogenerators and small producers, and a whole independent power industry was built on it. The next spring brought a shock of another kind when, in the early hours of March 28, 1979, a valve stuck open in Unit 2 at Three Mile Island and the reactor partially melted down, the most serious accident in US commercial nuclear power. Its small releases had no detectable health effects. Even so, the cooling towers on the Susquehanna became a symbol overnight. The accident brought sweeping changes to emergency planning and operator training, and the NRC tightened its oversight. It also hastened the decline of new reactor building, and the next US plant authorized to begin construction came in 2012.
On the map: The map marks Three Mile Island Unit 2, in the Susquehanna south of Harrisburg, as a historic grid site dated 1979. EIA lists Unit 1 as Crane Clean Energy Center: 803 MW, 1974, Constellation Nuclear, with out of service as its status. THREE MILE ISLAND, to the east, is a 500 kV substation in the index.
Sources: Public Law 95-617 (govinfo), 16 U.S.C. 824j (Cornell LII), Wikipedia: PURPA, NRC, Wikipedia: Three Mile Island accident
Restructuring: the ISOs (1992–2002)
PURPA's independent generators soon hit a wall. They could build a plant, but to sell its power to anyone except the local utility they had to use wires that utility owned and had every reason to keep to itself. Congress and FERC took that wall down in stages, starting with the Energy Policy Act of October 24, 1992, which opened transmission to wholesale generators. FERC Order 888, issued April 24, 1996, required open-access tariffs, so that every transmission owner offered its lines to competitors on the terms it gave itself. Order 2000, issued December 20, 1999, invited utilities to form RTOs and hand the running of their grids to an independent operator. The old Pennsylvania-New Jersey pool, by now PJM, became an ISO in 1997 and the first fully functioning RTO in 2002, running markets in which generators compete to serve the load. Other regions followed, and about two-thirds of US electricity consumers now live where an ISO or RTO manages transmission.
On the map: The dashed outlines are the ISO and RTO markets the map draws over its four interconnections: PJM, CAISO, SPP, MISO, NYISO and ISO-NE, which answer to FERC; ERCOT, which answers to the Texas PUC; and the Canadian operators to the north. The view is fitted to all of them.
Sources: 16 U.S.C. 824j, FPA section 211 as amended by the Energy Policy Act of 1992 (Cornell LII), Federal Register, 61 FR 21540 (govinfo), FERC Order No. 2000 (89 FERC 61,285), FindLaw, PJM history, US EPA, Power market structure
The California crisis and Path 15 (2000–2001)
No state went further than California, which with AB 1890 in 1996 restructured its entire industry around competition, and whose utilities sold much of their generation and bought power day by day in a new market. Within four years the design broke. From mid-2000 wholesale prices spiked to many times their old levels, while the utilities' retail rates stayed frozen. Stage 3 emergencies, the last step before operators shed load, rose from 1 in 2000 to 38 by May 22, 2001, and in January and March the state went through rotating outages. PG&E, the largest utility in the state, sought Chapter 11 in April 2001. On September 20, 2001 the CPUC suspended retail choice. The causes were many, from drought in the Northwest to traders who gamed the rules, and one of them was a bottleneck in the Central Valley. Path 15, the link between the northern and southern halves of the state, was so congested that power could not move freely between them. A new 500 kV line on it came in 2004.
On the map: LOS BANOS, ringed, and GATES to its southeast are 500 kV substations in the map's index; the lines shown are the map's 400 to 599 kV class. The view is fitted to the corridor between them.
Sources: EIA, PBS Frontline, CPUC D.03-05-083, WAPA, California Senate Energy Committee, Wikipedia
The 2003 blackout and the Energy Policy Act of 2005
Thirty-eight years after the 1965 blackout, NERC's reliability rules were still voluntary, and on a hot August afternoon in northern Ohio that finally caught up with the industry. At 1:31 pm on August 14, 2003, FirstEnergy's Eastlake 5 on Lake Erie tripped offline, a loss the system should have ridden through. After 2:14, though, the alarm system in FirstEnergy's control room failed without anyone noticing, and its operators did not know their picture of the grid had frozen. One after another, its heavily loaded 345 kV lines sagged into trees that had grown too close, and tripped. After 4:00 pm the cascade broke loose, and within minutes it had reached 50 million people across eight states and Ontario. Congress answered with the Energy Policy Act of 2005, which made reliability standards mandatory, with penalties behind them, and the first were enforceable from June 2007.
On the map: The shaded area is the map's approximate extent of the blackout of August 14, 2003, read from the task force's own map: New York and Ontario drawn whole, and counties in Ohio, Michigan and New Jersey. The ring is the Eastlake plant on Lake Erie, a historic site dated 2003 that ran from 1953 to 2015; no plant entry remains.
Sources: US-Canada task force report (2004), 16 U.S.C. 824o (Cornell LII), Federal Register, Order No. 693 (govinfo), Troutman Pepper, Wikipedia: NERC
Order 1000 (2011)
By 2011 the strongest winds in the country were blowing across places the grid had never needed to reach. The best of them swept the Dakotas, Iowa and Minnesota, hundreds of miles from the cities that would buy the power, and a line to carry it might cross the territory of half a dozen utilities, each asking why its own customers should pay. On July 21, 2011 FERC issued Order 1000. Every transmission provider now had to plan regionally with its neighbors, with a cost allocation method to match, weigh the needs that public policy created, and give up the federal right of first refusal that had let incumbents claim new lines as their own. FERC had already approved MISO's cost sharing in 2010, and on December 8, 2011 MISO's board approved 16 new Multi-Value Projects, a $5.1 billion portfolio, much of it 345 kV line across the Upper Midwest. Thirteen years on, in May 2024, FERC's Order 1920 found the rules lacked a long-term view and required plans counting benefits over at least 20 years.
On the map: The lines shown are the map's 300 to 399 kV class. 271 lines at 345 kV in Minnesota, Iowa, Wisconsin and the Dakotas, counting any that cross a state line, come to about 12,500 km. The view is fitted to the Upper Midwest.
Sources: Federal Register, 76 FR 49842 (govinfo), FERC, Ameren, Davis Wright Tremaine, January 2011, Federal Register, 89 FR 49280, Order No. 1920 (govinfo)
Gas passes coal (2016)
While planners argued over wires, the ground under the industry shifted. Horizontal drilling and hydraulic fracturing opened shale formations from Pennsylvania to Texas, and natural gas became cheap and plentiful in a way few had predicted. Coal had led US generation for decades. Gas first beat it for a single month in April 2015, and in 2016, by EIA's count, natural gas provided 34% of US electricity generation and passed coal to become the leading source, chiefly on its cost against coal. At West County Energy Center, FPL's three combined-cycle units began serving customers in August 2009, November 2009 and June 2011, about 1,250 MW each, wringing far more electricity out of every unit of fuel than the steam plants of an earlier age.
On the map: West County Energy Center, in western Palm Beach County, Florida, is 3,777 MW on the map with 2009 as its year, the largest gas plant the map lists as operating. Across the map, 1,920 gas plants listed as operating come to about 520 GW; 188 coal plants listed as operating come to about 164 GW.
Sources: EIA, FPL, EIA, March 16, 2016
Winter Storm Uri (2021)
In mid-February 2021 an arctic air mass settled over Texas and would not leave, and the separate grid that the Vernon fight had preserved learned how alone it was. Wells and pipelines froze, cutting off the gas that plants needed, and units of every fuel tripped in the cold. ERCOT says about 48.6% of its generation was forced out at the peak. With demand far above what was left, operators ordered controlled outages to prevent a statewide blackout, one that ERCOT said could have taken months to recover from. They held the grid together, at a terrible cost. FERC, NERC and the regional entities reported on November 16, 2021 that it was the largest controlled firm load shed in US history, and millions of Texans spent days without heat or light in freezing weather. Texas's Department of State Health Services confirmed 246 storm-related deaths in 77 counties. In February 2023 FERC approved NERC's extreme cold weather standard for generators, EOP-012-1, requiring plants across the continent to prepare for the kind of cold that broke Texas.
On the map: The shaded area is the map's approximate extent of the February 2021 storm's outages: ERCOT's footprint rather than all of Texas, plus Nuevo León, Coahuila, Tamaulipas and Chihuahua, every part of it overstated. The event's own record says more than 4.5 million people in Texas lost power.
Sources: ERCOT, Texas DSHS, FERC and NERC, UT Austin Energy Institute, Federal Register, 88 FR 14994 (govinfo)
The interconnection queue (2023–2025)
By the 2020s a developer could put up a solar farm in a year or two and then wait far longer for permission to plug it in. Before a plant can join the grid, the grid operator has to study what it will do to the system and who must pay for the upgrades, and thousands of projects, most of them solar and batteries, were waiting in line for those studies. LBNL's Queued Up report of June 2026 puts numbers on the wait. Of the projects requested from 2000 to 2020, about 19% had reached operation by the end of 2025. The median project built in 2025 took 61 months from request to operation, against 22 months in 2008. FERC's answer was Order 2023, issued July 28, 2023, which moved queues from first-come, first-served to first-ready, first-served cluster studies. LBNL says it is too early to judge its full effect, and that the delays raise concerns for meeting growing demand.
On the map: Each ring is a request in an interconnection queue, drawn at its county; the largest requests appear first, the rest as you zoom in. ERCOT holds 1,782 of the map's 8,406 active requests from LBNL's Queued Up, more than any other region: about 410 GW, among them 651 battery, 524 solar with battery, 347 solar, 139 wind and 96 gas.
Sources: LBNL, Queued Up 2026, Federal Register, 88 FR 61014 (govinfo), LBNL
Data Center Alley, inside PJM (now)
Along the country roads of Loudoun County, west of Washington, the buildings are long and windowless and hum day and night. They hold the servers behind much of the internet, and more and more the machines that train artificial intelligence, and a single campus can draw as much power as a small city. A 2024 state study by Virginia's JLARC found Northern Virginia the largest data center market in the world, with 13% of reported global capacity. All of it sits inside PJM, the grid that began as three companies sharing a ring of wire in 1927. PJM's January 2026 forecast put its summer peak at 156,373 MW for 2026 and 191,017 MW for 2031, with data center load behind its members' large-load adjustments. After years of nearly flat demand, the grid is being asked to grow quickly again. Edison's First District covered a quarter of a square mile. The grid that grew from it now spans a continent, and here in Loudoun County it is being pushed harder than it has been in a generation.
On the map: Data centers cluster in Loudoun County, west of Washington, inside PJM, which grew from the 1927 pool of stop 7. BRAMBLETON, ringed, is a 500 kV substation in the index with PJM as its balancing authority. Virginia has 489 of the map's 2,764 existing data centers, more than any other state (Texas 274, California 155), and all of Virginia's sit in PJM's area.
Sources: JLARC, Loudoun County, PJM Inside Lines, PJM 2026 load forecast report