LEARN / GLOSSARY
Interconnection
One word carrying two unrelated meanings in constant use: a synchronous grid covering much of a continent, and the process by which a single project connects to that grid. Almost every ambiguity in power coverage traces to this.
Two definitions
The system. An interconnection is a wide-area synchronous grid in which every generator turns in step with every other. The contiguous United States has three: Eastern, Western and ERCOT. They operate independently with very limited transfer between them, because their alternating currents are not in phase and moving power across a boundary requires direct-current equipment installed for the purpose.
The process. Interconnection is also the study and approval procedure by which a generator or a large load connects to the transmission system. This is the sense used in “interconnection queue” and “interconnection agreement”.
Measurement noteThe two senses are not related and are routinely mixed in the same paragraph. A statement that a project is “waiting on interconnection” concerns the process. A statement that surplus power cannot reach a region “because of the interconnection” concerns the system. Reading one as the other produces a confident conclusion about the wrong constraint.
Why it matters for capacity
Both senses bind industrial siting, separately. Which system a site sits in determines what generation can physically serve it. Which process applies determines how long connecting will take and who pays for the upgrades.
Related terms
Balancing authority · Interconnection queue · Regional transmission organization
Appears in
What Is the Electric Grid?
Why Electricity Demand Is Growing Again