New Zealand’s energy debate is not simply a choice between liquefied natural gas and renewable electricity. The real question is how Aotearoa should manage the difficult transition from declining domestic gas supplies towards a much more renewable electricity system while keeping the lights on, industry operating and power prices under control.
At the centre of that debate is a proposed $1 billion-plus LNG import terminal.
Supporters see imported LNG as a temporary insurance policy that could provide electricity and industrial backup during dry years, winter demand peaks and periods of low renewable generation.
Critics argue that investing heavily in imported fossil-fuel infrastructure risks locking New Zealand into expensive overseas gas, increasing exposure to international energy prices and diverting money from renewable generation, electricity storage and demand-side solutions.
The argument therefore comes down to a fundamental strategic choice:
Should New Zealand buy a fossil-fuel safety net while building the renewable system of the future, or spend that money accelerating the renewable system fast enough that the safety net is no longer required?
Why New Zealand has an energy security problem
New Zealand already generates most of its electricity from renewable sources, particularly hydro, geothermal and wind.
But that high renewable share creates a particular vulnerability.
Hydroelectricity is critically dependent on rainfall and snowmelt.
Unlike countries with enormous hydro reservoirs capable of storing several years of energy, New Zealand has relatively limited hydro storage. That means an extended period of low inflows can quickly reduce the amount of electricity available from hydro stations.
This is the country’s dry-year problem.
At the same time, electricity demand can surge during cold winter conditions.
If hydro lakes are low and wind generation is also weak, the electricity system needs another source of generation capable of switching on when required.
Historically, that role has largely been filled by thermal generation using natural gas and coal, particularly at stations such as Huntly.
The difficulty is that New Zealand’s domestic natural gas fields are declining.
Fields including Māui and Pohokura are maturing, meaning less locally produced gas may be available for electricity generation and industrial users.
This is the problem imported LNG is intended to solve.
The case for LNG
Supporters of LNG describe it as an energy security backstop rather than a replacement for renewable generation.
The proposition is that LNG would rarely need to dominate electricity production. Instead, it would be available when the renewable system comes under stress.
There are several key arguments.
Dry-year insurance
When hydro storage falls significantly below normal levels, thermal generation becomes increasingly important.
Imported LNG could provide fuel for gas-fired electricity stations when domestic gas is unavailable or insufficient.
In this sense, LNG functions much like insurance.
It might sit unused for long periods, but its availability could prevent severe shortages during an unusually dry winter.
Declining domestic gas
New Zealand currently relies on natural gas for electricity generation, industrial processes and parts of the commercial economy.
If domestic gas production falls faster than alternatives can be built, the country could face an energy shortfall.
LNG provides a way of replacing declining domestic supply without immediately abandoning gas-dependent infrastructure.
Supporting more renewables
One of the less obvious arguments for LNG is that it could actually make renewable investment easier.
Wind and solar are intermittent.
Their output depends on weather conditions.
Developers, generators and the wider electricity system therefore need confidence that electricity will still be available when wind and solar output is low.
Supporters argue a reliable gas backup could make it safer to build more wind and solar because the system would have firm capacity available when renewables temporarily underperform.
Industrial security
Some industries depend on gas for high-temperature processes that are not easily electrified.
Imported LNG could therefore provide continuity for industrial users while alternative technologies develop.
From this perspective, the LNG debate extends beyond electricity generation.
It is also about whether declining domestic gas could force factories to reduce production or close before viable replacements are ready.
Why critics oppose LNG
Opponents accept that New Zealand has an energy security problem.
They disagree that imported LNG is the best answer.
Their principal concern is that a temporary solution could easily become a long-term dependency.
Imported LNG could be expensive
LNG is not simply natural gas arriving through a pipeline.
Gas must first be cooled to around minus 162 degrees Celsius, converted into liquid, loaded onto specialised ships, transported internationally, unloaded and converted back into gas.
Every stage adds cost.
That means imported LNG could be significantly more expensive than gas historically produced within New Zealand.
If expensive LNG-fired electricity is required during periods of high demand, critics warn that it could contribute to higher wholesale electricity prices and ultimately higher bills for consumers.
Exposure to international markets
Domestic gas prices are primarily influenced by conditions inside New Zealand.
Imported LNG exposes New Zealand directly to international gas markets.
Prices can change dramatically because of wars, weather, competition from Asia and Europe, shipping constraints and geopolitical disruptions.
The country could therefore exchange one form of energy insecurity — declining domestic gas — for another: dependence on an internationally traded fuel whose price New Zealand cannot control.
Fossil-fuel lock-in
A $1 billion-plus terminal would represent a substantial capital investment.
Once built, there would inevitably be commercial and political pressure to use it.
Environmental groups therefore fear a facility described initially as transitional infrastructure could remain operating for decades.
That could make it harder for New Zealand to meet emissions targets and reach net zero.
Opportunity cost
Perhaps the biggest criticism is not simply that LNG costs money.
It is what else could be built with that money.
More than $1 billion could support significant investment in:
- wind generation,
- solar generation,
- geothermal,
- transmission infrastructure,
- demand-response programmes,
- grid-scale batteries,
- electricity efficiency,
- distributed household energy,
- or long-duration storage.
Critics therefore ask whether investing in LNG delays precisely the projects needed to make LNG unnecessary.
New Zealand’s dry-year risk explains much of the argument
Understanding the LNG debate requires understanding New Zealand’s hydro system.
Transpower and the Electricity Authority monitor the amount of water stored in major hydro lakes and compare it with historical patterns.
They use Hydro Risk Curves to assess whether the system is heading towards an electricity shortage.
These curves effectively operate as escalating warning levels.
Nominal risk
When storage begins falling below the nominal curve, the system enters a more closely monitored position.
Generators, Transpower and market participants begin paying greater attention to future inflows and available thermal generation.
Alert levels
If storage falls further, contingency measures become increasingly important.
Thermal generators may prepare additional fuel, major electricity users may reconsider consumption and the market begins planning for potential shortages.
Emergency conditions
At critically low storage levels, New Zealand could face formal conservation measures.
In an extreme scenario, insufficient generation could result in forced demand reduction or rolling blackouts.
That is the scenario LNG proponents say the country cannot afford to risk.
Current hydro conditions are relatively healthy
According to the figures supplied in the material, national hydro storage is currently around 125 percent of the historic mean.
South Island storage is particularly strong at around 130 percent, while North Island storage is tighter at approximately 87 percent.
Those figures suggest there is no immediate national dry-year emergency.
But they do not eliminate the structural problem.
Hydro storage conditions can change rapidly over a season, particularly if rainfall and snowmelt are weak while winter electricity demand remains high.
The material also notes that Meridian has arrangements involving additional contingent storage in Lake Pūkaki that could potentially provide another 545 gigawatt-hours if required during an emergency.
These storage figures are inherently time-sensitive and should be treated as a snapshot rather than a permanent condition.
Pumped hydro: the giant water battery
One alternative to imported LNG is pumped hydro storage.
Pumped hydro uses two reservoirs at different elevations.
When electricity is abundant and cheap, pumps move water uphill into the higher reservoir.
That effectively stores energy.
When electricity is needed, the water flows downhill through turbines and generates electricity.
The same water can therefore be cycled repeatedly.
Charging
When wind farms, solar farms or other generators produce surplus electricity, that energy powers pumps moving water uphill.
Discharging
When renewable generation is low or electricity demand is high, the stored water is released through turbines.
Pumped hydro therefore acts as an enormous rechargeable battery.
Lake Onslow was the big version
New Zealand previously investigated an enormous pumped-hydro development at Lake Onslow in Central Otago.
The attraction of Onslow was scale.
A sufficiently large scheme could potentially store enough energy to address the dry-year problem over weeks or months.
But estimated costs rose dramatically, eventually reaching figures of more than $8 billion, while concerns were also raised about environmental impacts, construction complexity and the effect such a huge intervention could have on the electricity market.
The project was cancelled.
That does not mean pumped hydro has disappeared from the debate.
Smaller regional schemes remain possible, but none currently offers the enormous seasonal storage capacity envisioned for Onslow.
Batteries and pumped hydro solve different problems
One of the most important distinctions in the energy debate is between battery energy storage systems — BESS — and pumped hydro.
They are both storage technologies, but they operate on dramatically different timescales.
Batteries
Grid-scale lithium-ion batteries are excellent for short-duration problems.
They can respond almost instantly.
They can absorb excess electricity during periods of low demand and release it during evening peaks.
They can stabilise frequency and help manage fluctuations in wind or solar production.
But most current utility batteries provide only a few hours of full-power discharge.
That makes them ideal for daily balancing.
It does not make them a complete solution for a national dry year.
Pumped hydro
Pumped hydro requires much larger upfront investment and geographic space.
But it can store vastly greater amounts of energy and potentially discharge over weeks or months.
Infrastructure can also operate for many decades.
This makes pumped hydro more suitable to seasonal electricity security.
The key distinction
A battery can help get New Zealand through a difficult evening.
Large-scale pumped hydro could help get New Zealand through a difficult winter.
LNG can also provide energy for extended periods, provided fuel shipments remain available.
That is why there is no single storage technology that automatically solves the entire problem.
Why batteries alone cannot currently solve a dry year
The difference comes down to scale.
A one-gigawatt battery capable of operating for four hours contains four gigawatt-hours of energy.
A major dry-year shortfall could involve thousands of gigawatt-hours across weeks or months.
Building enough conventional batteries to store that volume of electricity would be extraordinarily expensive with current technology.
Battery costs are falling and new chemistries may provide longer-duration storage in future.
But based on current technologies, batteries are primarily a short-duration balancing solution rather than a complete seasonal storage solution.
This is why the main contenders for deep dry-year resilience remain combinations of:
- thermal generation,
- imported fuel,
- hydro flexibility,
- geothermal,
- long-duration storage,
- demand reduction,
- and potentially pumped hydro.
Geothermal provides another advantage
Geothermal occupies a particularly important position in New Zealand’s energy system.
Unlike wind or solar, geothermal generation is not heavily dependent on weather.
It can provide steady electricity day and night.
Expanding geothermal therefore reduces the amount of backup required from other sources.
However, geothermal resources are geographically constrained and development takes time.
It also has environmental and iwi considerations that need to be managed.
Geothermal can substantially improve system resilience, but it is unlikely on its own to provide the full capacity needed during a severe dry year.
Demand response is another part of the solution
The energy debate frequently concentrates on generating more electricity.
But reducing or shifting demand can also improve reliability.
Large industrial electricity users can sometimes reduce consumption during periods of system stress in exchange for financial incentives.
Smart appliances and electric vehicle charging could increasingly shift household demand away from peak periods.
Industrial demand response could help avoid firing up expensive thermal generation during short supply shortages.
Energy efficiency can reduce total demand altogether.
These solutions do not remove the seasonal storage problem, but they reduce its size.
How the wholesale electricity market works
The LNG debate also matters because of how New Zealand’s wholesale electricity market sets prices.
Generators offer electricity into the wholesale market.
Transpower, acting as system operator, schedules generation to ensure enough electricity is produced to meet demand every half hour.
Generators are generally dispatched from lower-cost offers upwards until enough electricity is available.
The cost of the most expensive generator required to meet demand helps establish the wholesale spot price.
This is known as marginal pricing.
Why expensive gas can affect everyone’s electricity price
Imagine hydro, wind and geothermal can satisfy almost all electricity demand at a relatively low cost.
Then demand increases.
A gas-fired station is required to produce the final portion.
If that gas-fired electricity is much more expensive, it can raise the wholesale clearing price for the market during that trading period.
This is one reason consumer advocates worry about LNG.
If imported LNG costs substantially more than domestic gas, then electricity produced from LNG could be extremely expensive during supply shortages.
Even if LNG generation represents only a small portion of total generation, its role as the marginal generator could influence the wholesale market price.
Exactly how this flows through to household bills depends on retailers’ hedging arrangements, contracts and market exposure.
Location also affects prices
New Zealand uses locational marginal pricing.
Electricity prices are calculated at numerous points across the network.
Transmission constraints and losses mean electricity is not always worth the same amount everywhere.
For example, large amounts of cheap hydro electricity may be generated in the lower South Island.
But transporting that electricity to Auckland requires transmission capacity and results in energy losses.
If the grid becomes congested, wholesale prices can diverge significantly between locations.
This means energy security is not only about building enough generation.
New Zealand also needs enough transmission capacity to move that electricity to where it is required.
The major players
New Zealand’s electricity system involves several interconnected groups.
Generators
Companies such as Meridian, Contact, Mercury and Genesis operate hydro, geothermal, wind and thermal generation.
Gentailers
Many major generators are also electricity retailers.
This combination is known as the gentailer model.
Transpower
Transpower owns and operates the national high-voltage grid and acts as electricity system operator, balancing supply and demand.
Distribution companies
Local lines companies such as Vector and Orion move electricity from the national grid through local networks to homes and businesses.
Retailers
Retail companies buy electricity through wholesale arrangements and sell it to consumers.
Hedging protects against extreme spot prices
Wholesale electricity prices can be highly volatile.
During periods of abundant hydro generation, prices can be relatively low.
During severe shortages, they can rise dramatically.
Retailers and large industrial users therefore rely on financial contracts known as hedges.
These contracts allow participants to lock in electricity prices or insure themselves against future price spikes.
Without hedging, a retailer selling customers electricity at fixed household prices could face enormous losses if wholesale prices suddenly increased.
The hedge market is therefore an important part of electricity security alongside physical infrastructure.
The real LNG question
The strongest LNG argument is not that gas should replace renewable electricity.
Virtually nobody seriously proposing LNG suggests New Zealand should stop building wind, solar, geothermal or batteries.
The argument is about what sits behind those renewables when nature does not cooperate.
LNG supporters say:
Build renewables aggressively, but retain enough thermal backup to survive the worst conditions.
Critics say:
Every dollar spent creating imported fossil-fuel infrastructure is a dollar not spent making the renewable system sufficiently resilient to operate without gas.
Both sides are therefore debating the same transition.
They disagree about the bridge.
The economic question
A central challenge is comparing costs fairly.
A renewable generator and an LNG terminal perform different functions.
Wind and solar produce electricity frequently.
An LNG terminal might be required mainly during exceptional periods.
That means simply comparing the cost per megawatt-hour of wind generation with LNG generation can be misleading.
The system needs both energy and capacity.
An electricity source that operates only five percent of the time may nevertheless have enormous value if that five percent represents the moment when the country would otherwise face blackouts.
Conversely, maintaining billion-dollar infrastructure that is rarely used can also be extraordinarily expensive.
The crucial economic calculation is therefore:
What is the cheapest combination of generation, storage, transmission, demand management and backup that provides acceptable reliability?
That is the real system-planning question.
The climate question
The climate implications are equally significant.
New Zealand has committed to deep emissions reductions and ultimately net-zero emissions.
Building long-lived fossil-fuel infrastructure could make those objectives more difficult.
LNG also carries lifecycle emissions beyond simply burning the gas.
Methane can leak during extraction and processing.
Energy is consumed liquefying gas.
Shipping produces emissions.
Regasification requires further infrastructure.
Supporters argue these emissions may be acceptable if LNG is used rarely as emergency backup while the rest of the electricity system decarbonises.
Opponents argue that once a terminal exists, commercial incentives will encourage greater use than originally promised.
The energy sovereignty question
There is also a strategic dimension.
Domestic renewable energy uses resources New Zealand largely controls:
- rain,
- rivers,
- wind,
- sunshine,
- geothermal heat.
Imported LNG relies on international suppliers, shipping routes and global commodity markets.
Critics therefore frame renewable investment as a form of energy sovereignty.
The more energy New Zealand produces domestically from renewable sources, the less vulnerable it is to geopolitical shocks.
LNG supporters respond that energy security also means diversity.
Depending entirely on weather-dependent domestic resources can itself create vulnerability.
From that perspective, imported LNG diversifies risk rather than increasing it.
There is probably no single silver bullet
The material points towards a broader conclusion.
New Zealand is unlikely to solve its energy security challenge through one technology.
The eventual system could involve:
- much more wind,
- more solar,
- more geothermal,
- large battery systems,
- stronger transmission,
- smarter demand management,
- greater energy efficiency,
- hydro optimisation,
- additional contingent hydro storage,
- potentially smaller pumped-hydro projects,
- and some form of firm thermal backup during the transition.
The political argument is over how much of each should be built, how quickly, and whether imported LNG deserves a place in that mix.
The central trade-off
At its simplest, New Zealand faces two kinds of risk.
Build LNG and the country risks expensive infrastructure, higher exposure to international gas prices and fossil-fuel lock-in.
Do not build LNG and the country risks discovering during a severe dry year that renewable generation and storage were not expanded quickly enough.
One risk is financial and climatic.
The other is security of supply.
Neither is theoretical.
That is why the LNG decision is difficult.
Bottom line
New Zealand is not really deciding whether its future is gas or renewables.
Its long-term electricity trajectory is overwhelmingly towards greater renewable generation and electrification.
The harder question is what happens between now and that future.
Domestic gas supplies are declining before sufficient seasonal storage has been built.
Conventional batteries are excellent for hours but currently inadequate for storing an entire winter’s worth of electricity.
Large pumped hydro can provide seasonal storage but comes with enormous cost, environmental impacts and long construction periods.
Hydro remains highly valuable but vulnerable to rainfall.
Wind and solar are cheap and increasingly important but inherently variable.
Geothermal provides dependable renewable generation but cannot cover every shortfall.
LNG could provide firm backup, but at the price of major infrastructure investment, exposure to global fuel markets and continued reliance on fossil fuels.
So the real policy question is not:
LNG or renewables?
It is:
How much insurance should New Zealand buy against a dry-year crisis while it builds a renewable electricity system capable of no longer needing that insurance?
And behind that sits an even bigger question.
Should Aotearoa spend more than a billion dollars importing resilience — or invest that money in building resilience here at home?
