Changelog#

3.0.6#

Assumption changes

  • Updated gas supply projections to reflect Maui closure at the end of 2026.

  • Removed mining and construction from the list of subsectors where onsite anaerobic digestion is possible.

  • Updated some industrial sector ESD projection methods following review, most notably tying dairy processing demand to existing cattle stock projections.

  • Removed endogenous Methanex closure method, instead assuming closure when Maui closes end 2026.

  • Updated some heatpump costs following review.

Model fixes

  • Corrected a bug in NDGHG implementation that allowed coal to still be used for cooking post-2037.

  • Updated GIC demand data to reflect historical Methanex use more accurately.

  • Adjusted geothermal heatrates to better align with official statistics on primary energy.

  • Corrected a bug in diesel emissions for electricity generation.

  • Delayed convergence from empirical 2023 transport utilisation to harmonised within-bucket utilisation assumptions until 2035 (previously 2024), avoiding an abrupt shift immediately after the base year for some vehicle classes.

3.0.5#

Assumption changes

  • Solar generation capacity factors for different timeslices are now generated from NIWA EPW weather files using PVWatts, using MBIE’s October 2024 TMY3 (present climate) release.

  • Allowed the electricity sector to build new diesel peakers, using cost and efficiency assumptions from existing OCGT data.

  • Assumed all grid-scale solar utilised single-axis tracking technology.

  • Added or tweaked several new industrial technologies, allowing more flexibility in the demand end, including some hydrogen uses.

  • Added biomass as a fuel option for high-temperature heat in cement production to reflect the Golden Bay Cement biomass transition.

  • Added existing/known grid-scale battery installations.

  • Increased battery lifespan assumptions.

  • Increased geothermal generation lifespan assumptions.

  • Updated base year data to use latest release of EEUD, revising some figures.

Model features

  • Rebuilt hydrogen electrolysis methods to correctly utilise electricity demand.

  • Increased model detail of distributed solar, reflecting improved capacity factor from larger-scale rooftop installations.

  • Added a more robust demand-flex method. This means ripple control is reflected more accurately with minimal processing overhead. Scalable to other demand flex areas as needed.

  • Added more detail to near-term or historical modelled plant build timings, ensuring accurate partial generation when fully commissioned partway through a year.

  • Added new functionality to constrain capital uptake rates of selected technologies.

Model fixes

  • Resolved an error which led to excessive technology inflexibility in transport utilisation constraints. This allows for more realistic purchasing behaviour across different utilisation categories.

  • Disabled excessive optimisation of energy service demand between timeslices, which was leading to unrealistic demand flex behaviour. Note that this change also disables ESD timeslice reporting.

  • Corrected several links in biogas topology.

  • Resolved an issue that was leading to unrealistic switching behaviour in Other Industry demand.

3.0.4#

Assumption changes

  • Adjusted lightbulb lifetimes in residential and commercial sectors according to usage assumptions.

  • Ensured realistic minimum utilisation of peaking plants.

  • Slightly increased conservative hydro peaking contribution assummption to 90%.

  • Create “two-tier” LNG market, limiting its use to electricity generation.

Model fixes

  • Corrected implementation of new technologies for industrial applications.

  • Resolved a bug in implementation of 2037 coal boiler ban for intermediate process heat.

  • Resolved an issue that made industrial petrol engines more efficient than intended.

  • Resolved a bug leading to infeasible coal and biogas usage.

  • Added unallocated onsite generation to total system demand, ensuring system balance.

  • Add missing residential petrol emissions.

  • Allowed some industrial subsectors to electrify water heating using technologies already found in other subsectors.

3.0.3#

Features

  • Changed distributed solar process to use exogenous forecasts, providing more realistic results.

  • Rebuilt gas distribution network to allow for biomethane blending and more accurately represent maintenance costs as fixed, rather than per unit of throughput.

Assumption changes

  • Adjusted LNG terminal to fixed installation date in 2027 for Steady scenario. LNG remains excluded from Shift.

    • Also removed MIP functionality as this is no longer required.

  • Minor adjustments to capital costs for agricultural heating technologies following review.

  • Decreased average geothermal generation assumption slightly to align better with base year data.

  • Removed contingent gas from Steady scenario.

Model fixes

  • (Biofuel) Improved municipal waste production differences between scenarios.

  • (Gas supply) Fixed historical domestic field output levels.

  • (Electricity generation) Fixed incorrect wind availability curve assumptions.

  • (Electricity generation) Fixed dispatchable hydro and wind peak contribution factors not aligning with documentation.

  • (Agriculture) Improved modelling of geothermal heating for indoor cropping.

  • (Agriculture) Fixed a bug that meant agricultural energy emissions were counted incorrectly.

  • (Agriculture) Added greater distinction for refrigeration, offroad transport, and heating technologies.

  • (Agriculture) Resolved an issue that meant petrol-powered boats and farm bikes were more efficient than intended.

  • (Residential) Fixed an issue allowing too much flexibility in space heating technologies.

  • (Commercial) Added greater distinction for boilers, burners, and resistance heaters.

  • (Commercial) Fixed modelling of geothermal heating for education, healthcare, WSR, and other commercial sectors.

  • (Commercial) Resolved an error that led to some LPG, natural gas, diesel, and petrol technologies being cheaper than intended.

  • (Industry) Resolved an error that allowed Methanol and Urea to close different parts of their business at different rates.

3.0.2#

Features

  • Added more detail to residential load curves, allowing for different load profiles per use type.

  • Added an additional biofuel supply forecast scenario with AD feedstock growth and higher recoverability of biomass.

  • Separated biogas and biomethane modelling commodities, including a specific process for carbon scrubbing.

  • Added demand flex options for residential water heating, including splits between scenarios.

Model fixes

  • (Residential) Resolved an error that undercounted space heating demand in detached dwellings.

  • (Natural gas) Fixed a methodological error that double-counted domestic natural gas costs.

  • (Commercial) Resolved an error that left commercial heatpumps more expensive and with worse efficiency than intended.

  • (Residential, Commercial) Fixed a methodological error that overly restricted demand device time flexibility.

  • (Electricity generation) Ensured geothermal plants operate as baseload.

  • (Electricity generation) Resolved an error that limited hydro dam output flexibility.

Assumption changes

  • (Electricity generation) Adjusted Steady and Shift NREL scenarios from Conservative and Moderate to Moderate and Advanced, respectively.

  • (Commercial, Residential) Increased heatpump lifetimes slightly.

  • (Industrial) Removed some load curve assumptions.

3.0.1#

Features

  • Incorporated documentation into sphinx-based site for hosting on readthedocs.

  • Explorer now includes detailed transport demand, service, and capacity chart options.

Model fixes

  • (Biofuel) Ensured electricity demand was integrated into biofuel transformation processes.

  • (Commercial) Resolved an error that led to some demand technologies being cheaper than intended.

  • (Electricity) Ensured biogas and biomethane were made available as options for existing gas-fired plants.

  • (Electricity) Allowed Huntly Rankines to use black pellets.

  • (Transport) Ensured utilisation band constraints were properly fixed across model horizon.

  • (Transport) Resolved an error that led to electric heavy truck costs decreasing faster than intended in some scenarios.

  • (Transport) Resolved an error that led to some vehicle types having unrealistic utilisation rates.

3.0.0#

Features

  • Initial build of PREPARE-TIMES-NZ module, which creates TIMES-NZ model files based on hosted data and code.

    • All preprocessing methods migrated to python and open-sourced, to ensure replicability and tracability.

  • Initial build of TIMES-NZ-INTERNAL-QA module, which allows for post-processing and interrogation of model results.

    • Results hosted publicly and can be explored at the highest possible level of detail to ensure transparency.

  • Rebuilt and updated model for base year 2023 and new Steady and Shift scenarios.

On this page
Show Source