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NorthWestern Energy solar interconnection: what it requires before you energize

MT · checked 2026-07-03 · request an update

How does NorthWestern Energy detect unpermitted backfeed?

Being verified being verified

What happens if they catch you?

Being verified being verified

Small and DIY interconnection requirements

$25 interconnection agreement up to 100 kW, $25 update fee to add PV or batteries later. 1:1 net metering with no expiration on that agreement. reported

Sequence: application and approval, UL cut sheets, single-line diagram, site plan with AC and DC disconnects labeled and within 10 ft of the meter, homeowner permit, DIY install, electrician inspection and signature, county inspection, send signed forms to NWE, and only then export. reported

Contributed by u/rwright07, from a 9/2025 agreement

sources: NWE net metering & interconnection

Verify your export before NorthWestern Energy does

NorthWestern Energy nets your exports, but the meter still logs every reverse-flow interval, including ones you didn't plan. Worth knowing your real number before they do.

Clamp meter on the grid input · energy monitor on the export register

Building battery-first or zero-export anyway? Craftstrom · EZ-1 · EG4

Contains links to our partner sites. As an Amazon Associate we earn from qualifying purchases.

Related: Avista (WA)

Planning a zero-export or plug-in setup here? See the zero-export reality check and equipment notes.

Every claim above is evidence-graded: documented means it traces to the tariff or the utility's own filings, reported means a dated community report. The full table covers 60 utilities: see all of Gridrules.