American electricity demand barely moved for twenty years. From 2005 to 2019 it grew about a tenth of a percent a year, and the machinery built around that fact — the auctions that procure generating capacity, the rate cases that decide who pays for wires, the reliability standards that govern what may be connected — assumed a system that would grow slowly and predictably if it grew at all. Since 2020 demand has grown about 1.7 percent a year, and data centres are the primary reason. That single reversal is what this page is about: not what is being built, but what the electricity system does about it, and whose bill absorbs the difference.

The strain showed first in price, then in cost allocation. PJM's capacity auction — the market that pays generators to be available years ahead — has now cleared at its administrative price ceiling three times running, and even at the ceiling the most recent one fell 6.8 gigawatts short of the supply its own reliability standard requires; only 525 megawatts of new generation cleared. PJM's results report simulates that without a cap it would have cleared at $554.72 a megawatt-day region-wide and $776.69 in the Chicago area. Monitoring Analytics, the independent monitor of PJM's markets, attributes about $6.3 billion of that auction's $16.4 billion in charges to data-centre demand, and its president puts the cumulative figure at $29.4 billion over four auctions. That is the wholesale half. The retail half travels a quieter route: a Harvard Electricity Law Initiative review of nearly fifty rate proceedings found utilities using rate structures and non-public contracts to move the cost of infrastructure built for data centres onto ordinary customers, largely out of public view. By the end of 2025 the average residential price had reached about 19 cents a kilowatt-hour, some 27 percent above 2019; utilities requested more than $29 billion in increases in the first half of 2025 alone, double the year before, and households owed a record $25 billion in unpaid utility bills. Individual operators kept promising that none of it was theirs — a claim that keeps being made and has not yet been settled by any tariff or commission ruling. How much of that rise data centres actually caused is, on the backward-looking record, smaller than the wholesale numbers imply: Congress's research service, surveying the studies in September 2026, reports that the main driver of price increases from 2019 to 2025 was utility investment in ageing and hardening infrastructure, and that the states with the fastest data-centre growth generally saw prices fall — the extra demand spread fixed costs across more sales. The forward-looking models disagree with the rear-view mirror, projecting national increases of 6 to 29 percent as the load arrives.

Two things then changed the terms. The first was physical. A transmission fault in Ashburn, Virginia caused hyperscale facilities to transfer themselves to backup power, removing more than three gigawatts from the PJM system in seconds — and revealed that no reliability standard governs how a load that large is required to behave. Nobody shed it; the data centres left on their own protection schemes, which is how a three-gigawatt disappearance and "no load was shed" can both be true. The second was institutional, and followed directly. Federal regulators ordered the North American Electric Reliability Corporation to write mandatory standards for "computational loads" and criteria for registering the entities behind them by the end of 2026, with a second phase due the following March; NERC's first proposal would have registered any entity with at least 20 megawatts of connected load at a single high-voltage interconnection and at least a megawatt of computation behind it — a threshold reaching owners, tenants, colocation providers and hosts alike, without saying which of them carried the obligation. In August it revised that: two registrations, a Computational Load Owner and a Computational Load Operator, so the duty has a named holder, and — as compliance advisers read the revision — a threshold lifted to 50 megawatts. Weeks later PJM's board directed its own filing: a registry, a backstop procurement, and an interim service that would cut new large load within ten minutes of instruction, ahead of the emergency measures that reach everyone else — and at the end of July PJM lodged the backstop procurement as an actual case at FERC (docket ER26-3380-000), fixing the calendar the board had left open: a one-time auction bid this autumn, results by early December, accepted supply capped at $555 a megawatt-day against the $325 ceiling that bound the base auction. What began as directions to write rules has started to become filings: the PJM procurement is now a live case awaiting federal approval, while the NERC reliability standards are still to be written. Neither is in force.

Three questions are open, and they are the ones the record will settle. The first is who pays. Nothing in the federal architecture assigns retail costs to a named customer — PJM's board said so in terms, and said state action would be essential — so the allocation is being decided commission by commission, with the operator's own filing spelling out the default if a state does nothing: the cost falls on all load in the zone, including load that is not large, for fifteen years. The first commission to answer in the affirmative is Virginia's, which ordered Dominion Energy to write a tariff charging data centres and other large loads directly for the transmission their arrival requires — a network or substation upgrade that would not have been built but for a large customer is assigned to that customer — building on the 25-megawatt GS-5 rate class it created for January 2027. It is only a direction to develop the tariff, and the commission conceded it "may not address all instances", but it is the first concrete state instrument pointing the buildout's wire costs back at the buildout. The second is whether any of this produces measurement. The registries now being drafted would require per-site disclosure of location, load, ramp schedule and backup generation — figures no American operator publishes and no regulator currently holds — and whether they survive the rulemaking is a fair test of how much the new regime actually knows. The third is whether the demand is real. The five-year national peak forecast has risen more than six-fold in three years, to 166 gigawatts, and the same analysis that reported it cautioned that utility filings likely overstate 2030 data-centre load by roughly 40 percent; PJM raised its ten-year outlook and cut its near-term peaks in the same revision, on stricter vetting of speculative requests. The grid is being rebuilt, and repriced, around a number nobody has yet had to prove.