The prime minister has called it an “energy security crisis” and signalled a review of New Zealand’s electricity market as wholesale prices spike and industries suffer.
And he’s right – this year has seen pricing turmoil. August saw daily averages ranging between NZ$164.52 and $853.57 per megawatt hour (MWh). By comparison, August 2023 saw a maximum daily average price of $168.43 per MWh.
The Electricity Authority attributes this to a shortage of gas combined with low rain and inflows into our hydro lakes. The latter is a major concern. Storage levels are now around 800 gigawatt hours (GWh) less than the minimum levels in 2023, and more than 1,000GWh less than the historical mean for this time of year.
This is happening in the face of climate change, higher risk of dry years, and high projected growth in electricity demand. Electricity demand and generation scenarios released recently by the Ministry of Business, Innovation and Employment show this growth could be up to 82%, with a peak demand of between 9.1 and 12.5 gigawatts by 2050.
However, with greater electrification needed to decarbonise the economy, and aspirations to phase out all fossil fuels by 2030, some scenarios indicate the demand will be at least two to three times more. Of course, this means more generation capacity will be needed – 20 to 30 gigawatts above the current ten. The question is, can New Zealand do it?
Doubled capacity by 2030
The energy industry has been responding to these market signals, as highlighted in the government’s latest generation investment survey.
Committed and actively pursued projects will double generation capacity by the end of the decade. This will come largely from solar (6.4GW) and onshore wind (2.9GW), with smaller contributions from geothermal (0.6GW) and grid-scale batteries (0.6GW).
The first 35-megawatt battery facility was commissioned at Huntly this year. And battery capacity is important for stablising the grid and meeting peak demands. However, batteries will not address long-term storage of weeks and months, which is the focus of the NZ Battery Project.
The projected lesser investment in battery technology indicates a greater need to use hydropower capacity to compensate for the variability of solar and wind generation.
This “firming” of supply is based on the percentage of the year that a generation facility will provide power. For utility-scale solar it ranges between 19% and 26%, and for onshore wind between 33% and 55%.
Modelling by the Electricity Authority provides further insight on the firming that will be required. The analysis shows solar generation may be below 10% of the total capacity for 60% of the time. It will be above 50% of the overall capacity for 14% of the time.
Wind generation may be below 10% of the total capacity for 5% of the time, and above 50% of the capacity for 9% of the time over the entire country.
Renewables can meet future demand
Still, by 2030 we can expect around 11.5 terrawatt hours (TWh) a year from the new solar projects, and around 10.1TWh from the onshore wind projects. In total, this is about half the current yearly electricity demand.
Over the past decade, the country’s hydropower assets generated between 24 and 26TWh per year. So, to reach 100% renewable supply by 2030 (assuming biomass replaces coal at Huntley) will mean replacing between 3.5 and 5.6TWh of gas generation.
The battery capacity being developed won’t offset all of the gas generators currently used to respond to peak demands. If all of the batteries being developed participated in the market for four hours a day, they could provide around 1TWh over a year.
On a yearly basis, then, New Zealand can generate more than 47TWh from solar, wind and hydro, with some firming from the grid-scale batteries. That excludes the other baseload generators – geothermal, co-generation (where electricity is generated alongside heat production at industrial sites such as paper mills) and biomass.
In short, we should be able to meet our aspirations and the projected growth in energy demand by 2030.
Winter price spikes still likely
The challenge will be seasonal and daily power variations. The Electricity Authority analysis indicates wind generation should be reasonably consistent over the year. But there is an overall tendency to generate more during the day, typically peaking in the afternoons.
Solar generation, of course, will also peak in the early afternoons. But in winter it will generate a third less than in summer. This is important, given the risk of depleting hydro lake storage and running out of sufficient generation capacity in the grid.
The electricity system will need to cater for the lower solar generation in winter when hydro storage is at its lowest.
Morning and evening demand can be addressed, to some extent, with the rollout of rooftop solar, with batteries to store the solar electricity generated, augmented by the grid to charge the batteries if the sun doesn’t shine.
Nevertheless, with solar and wind offering lower market prices, we can probably expect wholesale prices to stabilise at reasonably low levels from the end of September to early May in a year without drought spells.
But winter may well still see price spikes if we don’t address seasonal storage. Scrapping most of the NZ Battery Project, as others have observed, may well prove shortsighted.
Alan Brent does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
A Sydney property developer lodged an appeal in court after being fined $3,000 by City of Canterbury Bankstown for destroying an oak tree. A council officer found excavation work at the builder’s Revesby construction site had compromised the structural stability of the tree.
Antidepressants have helped millions of people worldwide since the 1950s. But have you ever wondered what happens to these drugs once they leave our bodies?
We wanted to study the effects of pharmaceutical pollution on freshwater fish.
Our new research shows even low levels of the antidepressant fluoxetine – sold under the brand name Prozac, among others – will harm male guppies over time. In laboratory experiments, males exposed to fluoxetine at levels they would likely encounter in the wild suffered wide-ranging consequences.
As our reliance on medication grows, so too does the burden we place on natural systems. If we fail to understand the effects of pollution on wildlife, we risk compromising the health of our ecosystems and the services they provide.
Male guppies (above) are smaller than females (below) and more sensitive to environmental pollution.Per Harald Olsen, Wikimedia, CC BY
Drugs in our waterways
When we take our medicine, only some is absorbed by our bodies. Most passes through largely unchanged, in urine.
Wastewater treatment plants were not designed to remove these residues. So vast quantities of drugs are released into the environment, along with treated wastewater, worldwide.
This means organisms in waterways downstream from wastewater treatment plants are likely to be bathed in a cocktail of human medicines.
Over time, exposure to these contaminants can potentially disturb animal behaviour, physiology and reproduction. Of particular concern are drugs such as antidepressants, which have been specifically designed to alter brain chemistry in humans.
Pharmaceuticals designed for humans can affect fish and other species because they target receptors we have in common.
Prozac and other brands of fluoxetine increases levels of serotonin in the brain, which increases feelings of wellbeing and happiness. In fish, serotonin is also involved in reproduction, food intake and growth, stress and multiple behaviours.
What is surprising is most studies focus on short-term exposure, even though drugs such as fluoxetine can be highly persistent in the environment and affect fish over long periods.
We collected 3,600 wild guppies (Poecilia reticulata) from Alligator Creek in North Queensland. Water samples from the fish collection site showed no contamination with fluoxetine.
The guppy collection site.Jack Manera
Back at the lab, we exposed 15 successive generations of these fish to fluoxetine over five years.
Fish were randomly assigned to one of three levels of exposure, no fluoxetine (control), “low” or “high”. The “low” treatment level represents common surface water concentrations. “High” represents levels typically found in bodies of water heavily dominated by human effluent.
Sex in contaminated water
We found male guppies exposed to low fluoxetine levels were in poor condition, using a measurement similar to body mass index (BMI) in humans. The modified fin male guppies use to inseminate females (gonopodium) was also larger in these males.
Having longer gonopodia helps with mating. So exposure to fluoxetine seemed to trigger a trade-off between physical and reproductive health. When the maintenance of body condition became too costly, the fish put more energy into growing a larger gonopodium.
Low levels of fluoxetine also decreased sperm motility. This means the sperm of exposed males were poor swimmers compared to the sperm of unexposed males.
Female guppies are capable of mating with multiple males. So sperm from different males can compete within the female to fertilise the eggs. Lower sperm motility can therefore reduce the reproductive success of males exposed to fluoxetine.
Strangely, the low-fluoxetine treatment had stronger effects than the high-fluoxetine treatment. But this type of dose-dependent relationship is often found for such drugs and various mechanisms may be at play, such as desensitisation towards higher doses.
Under the influence
Aside from the effects on reproduction, we also studied how fluoxetine exposure affects the activity and hiding behaviour of guppies. Both behaviours are crucial to survival in the wild.
Male guppies exposed to fluoxetine became less capable of adjusting their behaviour in different contexts. They were repeatedly more consistent in their behaviour. In the wild, this can reduce an individual’s ability to respond to environmental changes. For example, consistent behaviour can make a fish an easy target for predators, while unpredictable behaviours can reduce their vulnerability.
Our findings add to a growing body of evidence showing similar behavioural disturbances in exposed wildlife. For example, other studies found antidepressants such as fluoxetine can make fish less active. This could disrupt their ability to compete for food and mates.
Why this matters
Antidepressants can be life-saving for people but pose problems when they find their way into the environment.
Our research has uncovered effects on fish that were largely underappreciated and overlooked, until now. The effects of prolonged exposure to such pollutants demands further investigation.
This will be crucial if we are to develop effective strategies for protecting and managing sensitive aquatic ecosystems, such as better wastewater treatment processes.
Upama Aich is employed under funding received by Bob Wong from the Australian Research Council.
Bob Wong receives funding from the Australian Research Council.
Giovanni Polverino works for the University of Tuscia. He receives funding from The Italian Ministry of Education, Universities and Research. He is affiliated with Monash University.
Australian study of guppies shows that pharmaceutical pollution could threaten species’ long-term survival
Contamination of waterways with the antidepressant Prozac is disrupting fish bodies and behaviours in ways that could threaten their long-term survival, new research has found.
Speaking during the Pacific Islands Forum in Tonga, the United Nations secretary general, Antonio Guterres, said fossil fuels must be phased out and all G20 countries must pursue a ‘drastic reduction of emissions’. Asked whether he believes it is acceptable for a country like Australia to be continuing to approve new coal and gas projects, Guterres said the ‘situation of different countries is different’ but there should be no ‘illusion’. ‘Without a phase-out of fossil fuels in a fair and just way, there is no way we can keep the 1.5 degrees alive,’ Guterres said in a reference to the Paris climate agreement goal of holding temperature rise to 1.5C above pre-industrial levels
