Transmission and grid interconnection

node · earth · global

The wires, and increasingly the binding constraint. Interconnection does two things for a variable system that nothing else does as cheaply: it aggregates weather, because wind output at sites five hundred kilometres apart is far less correlated than at sites five kilometres apart, and it connects generation to load, because the best wind and solar resource is usually not where the demand is. High-voltage direct current is the tool for long distances — losses of roughly three per cent per thousand kilometres, no reactive-power limit on cable length, and controllable flow — while alternating current remains the meshed network everything else hangs from. The problem is not technical but institutional and temporal. Transmission lines take a decade or more to permit and build in most jurisdictions, against two to four years for a solar farm and eighteen months for a battery, so the queue is the bottleneck: the IEA's 2023 grids report put the volume of projects waiting in advanced-stage interconnection queues worldwide at well over a terawatt, and estimated that on the order of eighty million kilometres of grid must be added or refurbished by 2040 for announced energy and climate goals to be met. In the United States the Lawrence Berkeley National Laboratory queue series has tracked active interconnection requests exceeding the entire installed generating capacity of the country. Cheap generation that cannot be connected is not cheap generation.