Decarbonisation of the electricity grid — new zealand (market-based)
New Zealand aims for a 100% renewable electricity grid by 2030. However, the country's heavy reliance on hydro generation causes significant year-to-year volatility in emissions due to "dry year" weather patterns requiring fossil-fuel backup. Concurrently, a growing voluntary REC market (NZECS and I-REC) allows corporations to claim renewable generation, which strips green attributes from the remaining residual grid mix. In a conservative scenario, the market-based (residual) factor remains volatile and elevated as corporate REC purchases concentrate fossil emissions into the remaining grid mix. An aggressive scenario projects a rapid drop to near zero by 2030 as the physical grid fully phases out fossil fuels, eliminating residual grid emissions entirely.
- Category
- Utilities
- Geography
- new zealand
- Basis
- market-based
- Unit
- kgCO2e / kWh
- Baseline
- Baseline 2024 → 2050
- Last updated
- Updated
Regions covered: nz-all
Also applies to: Companyvehicle Car Bev, Companyvehicle Hgv Bev, Companyvehicle Van Bev, Commuting Car Bev, Commuting Motorbike Bev
In a conservative scenario, the market-based (residual) factor remains volatile and elevated as corporate REC purchases concentrate fossil emissions into the remaining grid mix. An aggressive scenario projects a rapid drop to near zero by 2030 as the physical grid fully phases out fossil fuels, eliminating residual grid emissions entirely.
Projection chart
Cumulative percentage change in the emission factor from the 2024 baseline. Shaded band shows min–max range; bold line is the Viable Pathway mid projection.
Data table (Viable mid projection)
| Year | Min | Viable mid | Max |
|---|---|---|---|
| 2024 | 0.0% | 0.0% | 0.0% |
| 2025 | 0.0% | 0.0% | 0.0% |
| 2026 | 4.2% | -0.8% | -10.0% |
| 2027 | 8.4% | -1.6% | -20.0% |
| 2028 | 12.6% | -2.4% | -30.0% |
| 2029 | 16.9% | -3.3% | -40.0% |
| 2030 | 21.1% | -4.1% | -50.0% |
| 2031 | 21.1% | -7.6% | -60.0% |
| 2032 | 21.1% | -11.2% | -70.0% |
| 2033 | 21.1% | -14.7% | -80.0% |
| 2034 | 21.1% | -18.2% | -90.0% |
| 2035 | 21.1% | -21.8% | -100.0% |
| 2036 | 21.1% | -21.8% | -100.0% |
| 2037 | 21.1% | -21.8% | -100.0% |
| 2038 | 21.1% | -21.8% | -100.0% |
| 2039 | 21.1% | -21.8% | -100.0% |
| 2040 | 21.1% | -21.8% | -100.0% |
| 2041 | 21.1% | -21.8% | -100.0% |
| 2042 | 21.1% | -21.8% | -100.0% |
| 2043 | 21.1% | -21.8% | -100.0% |
| 2044 | 21.1% | -21.8% | -100.0% |
| 2045 | 21.1% | -21.8% | -100.0% |
| 2046 | 21.1% | -21.8% | -100.0% |
| 2047 | 21.1% | -21.8% | -100.0% |
| 2048 | 21.1% | -21.8% | -100.0% |
| 2049 | 21.1% | -21.8% | -100.0% |
| 2050 | 21.1% | -21.8% | -100.0% |
How the Viable mid projection is calculated
Weighted projection based on pedigree quality assessments, normalised to 2025 emission factor
Weighted projection between sources
Sources and scenarios
| Scenario | Source | Type | Ambition | Pedigree |
|---|---|---|---|---|
|
BraveTrace_slightincrease
This scenario assumes short term volatility continues with a slight increase (to 0.08) in factors in line with other geographies with increasing market purchases by corporates. This conservative case assumes weather volatility continues to dictate grid emissions, while corporate REC purchasing outpaces the construction of new physical renewable plants. As major corporations aggressively buy up NZ-ECs and I-RECs to meet RE100 and net-zero targets, the remaining "residual mix" becomes concentrated with the emissions from the fossil-fuel backup plants. New wind and solar projects face grid connection delays, meaning the physical grid doesn't get cleaner fast enough to offset the accounting impact of the REC purchases, leaving the market-based factor artificially high for non-REC buyers. |
BraveTrace - Slight Increase
The BraveTrace Network comprises all parties supporting the New Zealand Energy Certificate System (NZECS) for both renewable electricity and renewable gas. |
historic | base | 1.3512498725672673 |
|
BraveTrace_veryambitious
This scenario assumes New Zealand successfully executes its official ambition to reach a 100% renewable physical grid by 2030, rendering the REC accounting squeeze irrelevant. Massive capital deployment into grid-scale batteries, geothermal, and wind eliminates the need for thermal (gas/coal) backup even in dry years. Once fossil fuels are entirely pushed out of the physical generation mix, there are zero grid emissions to allocate. The location-based and market-based factors converge at zero, and the residual mix mathematically cannot be inflated by REC purchases. |
BraveTrace - Very Ambitious
The BraveTrace Network comprises all parties supporting the New Zealand Energy Certificate System (NZECS) for both renewable electricity and renewable gas. |
historic | very_ambitious | 2.4672150070488703 |
Changelog
- — Updated vpmid mid from blended projection (len=27); appended source1 from BraveTrace (historic) year=2025, pedigree_score=1.5306931967173178.
- — Recomputed vpmid mid as pedigree-weighted blend of 1 source(s).
- — Refreshed quality.recency and pedigree_score from publication years (as-of 2026). VP mid weights affected for: source1.
- — Updated vpmid mid from blended projection (len=27); appended source2 from BraveTrace (historic) year=2025, pedigree_score=2.5907319198577228.
- — Recomputed vpmid mid as pedigree-weighted blend of 2 source(s).
- — Updated source1 from BraveTrace - Slight Increase (historic) year=2025, pedigree_score=1.3512498725672673.
- — Recomputed vpmid mid as pedigree-weighted blend of 2 source(s).
- — Refreshed quality.recency and pedigree_score from publication years (as-of 2024). VP mid weights affected for: source2.
- — Updated source2 from BraveTrace - Very Ambitious (historic) year=2025, pedigree_score=2.4672150070488703.
- — Recomputed vpmid mid as pedigree-weighted blend of 2 source(s).
Frequently asked questions
What is driving decarbonisation of the electricity grid decarbonisation in new zealand?
New Zealand aims for a 100% renewable electricity grid by 2030. However, the country's heavy reliance on hydro generation causes significant year-to-year volatility in emissions due to "dry year" weather patterns requiring fossil-fuel backup. Concurrently, a growing voluntary REC market (NZECS and I-REC) allows corporations to claim renewable generation, which strips green attributes from the remaining residual grid mix. In a conservative scenario, the market-based (residual) factor remains volatile and elevated as corporate REC purchases concentrate fossil emissions into the remaining grid mix. An aggressive scenario projects a rapid drop to near zero by 2030 as the physical grid fully phases out fossil fuels, eliminating residual grid emissions entirely.
How does Viable Pathway calculate the mid projection?
Weighted projection based on pedigree quality assessments, normalised to 2025 emission factor Weighted projection between sources
What range of outcomes does this trend cover?
In a conservative scenario, the market-based (residual) factor remains volatile and elevated as corporate REC purchases concentrate fossil emissions into the remaining grid mix. An aggressive scenario projects a rapid drop to near zero by 2030 as the physical grid fully phases out fossil fuels, eliminating residual grid emissions entirely.
Discussion
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