Source
https://www.rewiring.nz/investing-in-tomorrow — original source (opens in a new tab; the file is not redistributed)
Rewiring Aotearoa (2024) — Investing in Tomorrow: The Electrification Opportunity
National macro case for household electrification — and the all-electric household energy budget
A peer-reviewed (Geoff Simmons) RA working paper co-authored by Saul Griffith + Paul Conway (Chief Economist, RBNZ) arguing household electrification (“sector coupling” of homes + vehicles) saves NZ ~
10.7bn/yr by 2040, cuts 10 Mt CO₂e/yr, and improves the balance of trade (NZ spends ~19.84bn/yr on mostly-imported fossil fuels). NI-load-bearing object: Figure 1 — average household energy falls from ~85 kWh/day (fossil) to ~25 kWh/day (all-electric), a 70% drop from electrification efficiency (vs −2% from insulation alone) — the all-electric demand profile for the demand-level lever. The most credible of the Rewiring Aotearoa publications held here, but still RA advocacy modelling → data_quality: medium.
Summary
The paper frames household electrification as a national investment: replacing fossil appliances + vehicles with electric equivalents plus rooftop solar and batteries yields large efficiency gains (an all-electric home uses 70% less primary energy than a fossil one), flattens volatile energy bills, and shifts spending from imported fuels to domestically-generated electricity. It quantifies per-household savings (1,485/yr at 5.5% finance, up to 4,699/yr at 1%), national savings (3.2bn/yr by 2030 → 10.7bn/yr by 2040; $95bn cumulative), emissions cuts (10 Mt/yr by 2040; 105 Mt cumulative to 2040), and the energy-productivity basis (EV 89% vs ICE 20.5%; heat-pump COP >400%). It closes on why this is not happening at pace — finance/credit access, information, workforce and supply-chain constraints.
Key claims
- claim: "Average NZ household energy use falls from ~85 kWh/day (fossil-fuel home: gas/LPG heating + petrol vehicles) to ~25 kWh/day when fully electrified (electric appliances + EVs) — a ~70% reduction from electrification efficiency alone. Conventional insulation + sealing (15% thermal improvement) cuts only ~2% (85→83 kWh/day); electrified + insulation = ~24 kWh/day. Vehicles dominate the fossil-home energy budget."
source_location: "Section 2, Figure 1, p.4"
- claim: "Energy-productivity basis: an EV converts 87–91% of input energy to motion vs 16–25% for a petrol ICE (~4×); a heat pump delivers 300–400% (COP, NZ average now >4.0) vs ~95% for gas/LPG; this is why electrification, not insulation, is the dominant efficiency lever."
source_location: "Section 2 p.5 + Section 4.1 p.9 (footnotes 6, 9, 10)"
- claim: "Driving cost (energy-productivity, $/100km, Figure 5): petrol ICE ~$20/100km; grid-charged EV ~$5/100km; rooftop-solar-charged EV ~$2/100km. Equivalent fuel-price framing: rooftop solar ≈ $0.31/L-equivalent vs grid electricity ≈ $0.64/L for an EV."
source_location: "Section 4.1 Figure 5 p.8 + Section 4 p.7"
- claim: "Per-household economics (Figure 4, from 'Electric Homes' 2024): annualised cost of a gas/LPG + petrol home ≈ $18,445–19,137/yr vs an electrified home with 7 kW solar + 7 kWh battery ≈ $17,306/yr → savings ~$1,485/yr at 5.5% finance, up to ~$4,699/yr at 1% finance. A gas connection's fixed charge (~$689/yr, May 2024) is eliminated by going all-electric."
source_location: "Section 4 Figure 4 p.8 + Section 4.2 p.9"
- claim: "NZ retail fossil-fuel spend 2023 ≈ $19.84 billion/yr: petrol 100.9 PJ $7.72bn; diesel 149.9 PJ $7.81bn; natural gas 113.6 PJ $1.53bn; LPG 9.7 PJ $567M; coal 41.0 PJ $625M; aviation (dom 18.4 PJ $478M + intl 39.2 PJ $1.02bn); fuel oil 5.9 PJ $87M. ~Two-thirds of NZ energy is from (mostly imported) fossil fuels; NZ used ~2.9bn L petrol + 3.9bn L diesel in 2023."
source_location: "Section 5.1 table p.11"
- claim: "National savings + emissions (Figures 10–11): household + vehicle electrification saves ~$3.2bn/yr by 2030 and ~$10.7bn/yr by 2040 (real $2024), $95bn cumulative by 2040; emissions fall 10 Mt CO₂e/yr by 2040 (105 Mt cumulative 2024–2040, 212 Mt by 2050). Modelled on 15-yr machine life, ~5-yr supply ramp, EV–ICE cost parity ~2028."
source_location: "Section 5.3 Figs 10–11 pp.13–14 + Section 6 p.15"
- claim: "Context: 88% of NZ electricity production was renewable (2023) but only ~30% of NZ final energy consumption is renewable; NZ rooftop-solar uptake ~2.7% of households vs Australia ~35% (avg AU system >9 kW). Resilience framing: 2023 Auckland floods (1-in-200-yr) + Cyclone Gabrielle + 2011 Christchurch quake → solar + battery backup as disaster resilience."
source_location: "Section 5.1 p.12 + Section 3.2 p.6 + Section 3 p.7 (resilience)"Neobiome Intelligence relevance
The macro + whole-household complement to the other Rewiring Aotearoa sources. Its standout NI input is the all-electric household energy budget (~25 kWh/day, ~9,125 kWh/yr) vs the fossil baseline (~85 kWh/day) — the empirical anchor for the “high-end all-electric” tier of the pending demand-level lever (matches the ~27 kWh/day all-electric figure already in OT_029). The **EV /100km ladder** (petrol ~20 / grid-EV ~5 / solar-EV ~2) is the running-cost basis for bringing EVs into the demand/economics scope. The energy-productivity multipliers (heat-pump COP 4.0, EV 89% vs ICE 20.5%) corroborate the heat-pump↔electricity coupling already in the heat slice. The national figures (19.84bn fossil spend, 10.7bn/yr savings) are thesis-macro, not model cells. Caveats: advocacy modelling (peer-reviewed but not journal); the 85→25 kWh/day is a per-household average from RA’s model + Residential Baseline Study 2021; figures real-$2024 nominal forecasts.
Research targets
Documents to retrieve
- RT_237 — Residential Baseline Study 2021 (the NZ appliance/household energy-use dataset underpinning RA’s 85→25 kWh/day household energy model): candidate primary for the NI demand-level (all-electric) profile.
Research gaps
- The 85→25 kWh/day budget is a national average; an NI all-electric demand-level profile should reconcile it against OT_029’s ~27 kWh/day and the Residential Baseline Study (RT_237) before use as a model default.
Connections
Links to
Sources (1): OT_029
Referenced by
EDT domains (2): D01: Renewable Energy & Storage Systems · D05: Smart Mobility & Electrified Transport
SSI indicators (1): I01: Financial & Economic Self-Sufficiency
Sources (1): OT_070