The connection rulebook is now the binding constraint, not the hardware
Serguey Asael Shinder2 min readThree items today, three jurisdictions, no connection between them, and all three are about the same thing: the rules for being allowed to connect. Not what the equipment can do — whether the system will let it in, and on what terms.
Texas adopted large-load interconnection standards and dropped the $50,000/MW non-refundable fee it proposed in March, settling on a flat $100,000 study fee. It also extended the window for telling ERCOT about missed energisation milestones from six months to twenty-four, applied to the schedule as a whole. This lands while the state is auditing an interconnection queue of 474 GW that is roughly 90% data centres.
Chile's system operator ran its first grid-forming field tests, and the stated purpose was to generate data for verification criteria — the requirements a grid-forming resource must satisfy before it is admitted. The requirements were published first, in April 2025, and a verification guide followed in May 2026.
ACER approved TSO proposals to further harmonise prequalification for balancing service providers across the PICASSO and MARI platforms.
Interconnection queue rules, grid-forming verification criteria, BSP prequalification. Three names for admission control.
This is what a system looks like when the scarce resource stops being generation and starts being the right to attach to the network. For twenty years the hard question was whether you could build the thing. Increasingly the hard question is whether the operator will let you energise it, how long the answer takes, and what you must prove first.
Two consequences follow, and they point in opposite directions.
Admission rules are where discrimination hides, so harmonising them is worth more than it looks. ACER's prequalification work is the least dramatic item of the three and probably the most valuable: a battery that can technically provide balancing in one member state and cannot sell that service in another is being excluded by paperwork, not by physics. Reducing the number of national processes does more for cross-border liquidity than any change to the trading platform.
But admission rules are also the only queue-management tool that works on speculation, and Texas has just put one down. A non-refundable per-megawatt fee exists to make a speculative queue entry expensive. Removing it while auditing a queue that is 90% data centres means the speculation problem is being handed to the audit. Audits are retrospective; fees are continuous.
The pattern to take from all three: if you are planning around a connection, the document that governs your project is increasingly a procedural one — a verification guide, a prequalification standard, a milestone schedule — and it changes on a regulator's timetable rather than an engineering one. Chile's sequence is the one to copy: publish the requirement, then test the verification method against a real installation, then monitor in service. Requirements written after the fleet exists are how a grid ends up with plant it cannot characterise.