NZ rural grid line-extension + connection costs
Resolves RT_214 + RT_215 — the D21 / A2 grid-vs-off-grid breakeven inputs
A genuine multi-source synthesis (no single document gives the answer): EA regulator build rates → ~
100,000/km** rural line extension; Orion's published fixed contribution → ~**12,000 one-off connection; Powerco’s off-grid product → a ~1.5 km crossover beyond which standalone solar+battery wins. Replaces the model’s low-confidence placeholders (70k/km, 20k). The EA worked-examples + Orion methodology PDFs are filed as primaries. ⚠ the $/km is the highest-variance input in the whole grid-vs-off-grid comparison — keep it user-adjustable.
Source verification (audit 2026-06-22) — ESTIMATE, NO PRIMARY (headline values)
The build rates ARE verified — EA worked examples:
35/m overhead conductor,14,400/pole,140/m UG; Orion **9,000/premise** rural-single. But the model headline values are derivations no document quotes:grid_extension_cost100,000/km is a triangulation, and `grid_connection_fixed`12,000 is Orion’s $9,000 rounded up. Both demotedsourced→assumedin model_design.md (RT_214/RT_215 stay open).
Summary
For the model’s A2 grid-vs-off-grid (D21) decision, two NZD inputs were low-confidence placeholders. Triangulating the Electricity Authority’s published distribution-connection build rates (35/m overhead conductor + ~14,400/pole + design) against the Level/BRANZ anchor (“800 m of mains + transformer > 100,000") gives a central **~100,000/km** for rural three-phase overhead 11 kV/LV on moderate terrain — but the figure swings 5×+ with overhead-vs-underground, single-phase/SWER (50k/km) vs three-phase, and terrain (150–250k+/km underground/difficult), so it must be a user-adjustable input. The one-off fixed connection is anchored on Orion’s published rural fixed capital contribution (9,000/premise, eff. 1 Apr 2024), rounded to **~12,000** for a dedicated remote transformer. The crossover is bounded by Powerco’s off-grid “Base Power” product, whose 1 unit ≈ 1.5 km of lines and poles — beyond that distance a standalone solar+battery system ($40–100k typical NZ) is cheaper. This matches the lived view from Forest Lodge (Interview VIII [INT_008]): the off-grid decision is a cable-vs-setup economic crossover.
Key claims
- claim: "NZ rural grid line-extension cost ≈ NZD 100,000/km for 3-phase overhead 11 kV/LV on moderate terrain (fills grid_extension_cost_nzd_per_km, was a 70k placeholder). Triangulated from Electricity Authority published build rates (~$35/m overhead conductor + ~$14,400/pole + design) and the Level/BRANZ anchor ('800 m of mains + transformer > $100,000'). HIGH VARIANCE (5×+ across a single site): single-phase/SWER ~$50,000/km (capacity-limited); underground or difficult terrain $150,000–250,000+/km (EA 11 kV UG cable ~$140/m before trenching). Treat $100k/km as a central rural-overhead default exposed as a USER-ADJUSTABLE input, not a fixed constant — it is the least stable input in the grid-vs-off-grid comparison."
source_location: "Electricity Authority — Worked examples of distribution connection pricing; Level/BRANZ"
- claim: "NZ one-off grid connection fixed cost ≈ NZD 12,000 (fills grid_connection_fixed_nzd, was a 20k placeholder) — transformer + connection/metering works, anchored on Orion's published rural fixed capital contribution of $9,000/premise (within 150 m, eff. 1 Apr 2024), rounded up for a dedicated small transformer at a remote site. Off-grid CROSSOVER ≈ 1.5 km of new line (range 0.4–1.5): Powerco's off-grid 'Base Power' product treats 1 unit as ≈ 1.5 km of lines and poles, so beyond ~1.5 km a standalone solar+battery system (NZ$40,000–100,000 typical) is cheaper than extending the grid. This is an EDB-validated breakeven, corroborated by int_008 (cable-vs-setup framing)."
source_location: "Orion connections & extensions methodology 2025; Powerco Base Power; MySolarQuotes/ZEN; int_008"Neobiome Intelligence relevance
Resolves RT_214 + RT_215 — firms the D21 / A2 grid-vs-off-grid breakeven. Two model inputs move from low-confidence placeholders to sourced figures:
grid_extension_cost_nzd_per_km70,000 → 100,000 (rural 3-phase overhead, central default).grid_connection_fixed_nzd20,000 → 12,000 (one-off transformer/connection).
And it supplies a defensible off-grid crossover ≈ 1.5 km (Powerco’s own product economics) — a direct empirical check on the model’s grid_extension_capex = grid_distance_km × cost_per_km + fixed breakeven, and a match to int_008 (off-grid is a cable-vs-setup economic crossover). ⚠ Build note: the /km is the single highest-variance input (overhead/underground, phase, terrain → 5×+) — it must stay a **user-adjustable** lever, with the 50k (SWER) and $150–250k (underground/difficult) variants documented.
Retrieval provenance
A multi-source synthesis; the two authoritative documents (EA worked-examples, Orion methodology) are filed as primaries and their figures quoted. The $100k/km is a derivation (EA per-metre rates × distance + transformer), not a single quoted headline — the apportionment is in the filed _derivation note. data_quality medium (derived + high site variance).
Research targets
Research gaps
- A clean per-EDB **rural overhead
/km** is not published as a single headline by any lines company — the100k/km is derived from unit rates + the Level/BRANZ anchor. To firm it, pull the EDB Connection Charges Price Schedules (per-metre over-allowance) for 2–3 lines companies (Orion, Powerco, Aurora, Top Energy).
Connections
Referenced by
Sources (6): CR_054 · OT_113 · OT_125 · OT_224 · REG_037 · URL_018
Technologies (2): Biomass District Heating (Wood Chip) · Micro-hydro (run-of-river, community-scale)
EDT domains (1): D01: Renewable Energy & Storage Systems