The man who came up with the idea of a Lake Onslow pumped hydro scheme says the Government was wrong to cancel research into it so soon after it was elected.
Earl Bardsley was speaking as renewed worries about the supply of electricity hit New Zealand for the second year in a row.
Bardsley is research associate at the School of Science at the University of Waikato, and campaigned many times for the Lake Onslow scheme. This project would have used cheap, off-peak electricity to replenish upper level reservoirs so water could run back down through turbines to generate electricity during times of peak demand, but would have cost billions to develop.
He says Lake Onslow was not necessarily "the best thing since sliced cheese," but research should have been continued into making a business case for Onslow, along with alternatively using either back-up geothermal or the burning of wood pellets at the Huntly thermal power station.
“I think it’s rather ironic that such a short time after that particular report was cancelled, we’re getting the situation where all those hydro schemes are running low," says Bardsley.
The NZ Battery Project was established within the Ministry of Business, Innovation & Employment (MBIE) in 2020 to explore possible renewable energy storage solutions for when New Zealand's hydro lakes run low for long periods. A pumped hydro scheme at Lake Onslow was one of the options being explored. The current government stopped the Lake Onslow investigations in late 2023, although MBIE continues work on the question of security of supply during extended periods of low hydro inflows as part of its wider electricity system work programme.
Ending work on the Lake Onslow project was a priority of the Coalition Government's 100-day plan, with Energy Minister Simeon Brown announcing in December last year all work had been halted.
"This hugely wasteful project was pouring money down the drain at a time when we need to be reining in spending and focusing on rebuilding the economy and improving the lives of New Zealanders," Brown said.
Tiwai Point scale back
Bardsley’s comments come after the latest symptom of NZ’s energy malaise was made public. This was the decision by the Tiwai Point aluminium smelter in Southland to cut its electricity consumption by 185 megawatts.
This is an increase on last week's pledge of a 100 megawatt cut, and is equivalent to 4% of the country’s total electricity use.
It will mean production at New Zealand Aluminium Smelter, which is majority owned by Rio Tinto, will be scaled back by one third.
New Zealand Aluminium Smelter’s chief executive, Chris Blenkiron, says this decision was made in response to a call from its majority supplier Meridian Energy to conserve electricity.
“With lake storage near their lowest levels historically, we will commence ramp-down to enable 185 MW to flow into the system, to help ease tight supply,” Blenkiron says.
“The team at Tiwai understand the importance of playing our part in the wider electricity system to ease the stress the system is now under, from tight hydro and gas supplies.”
While the undertaking given to Meridian lasts only until 24 September, the slow, subsequent ramp-up of the idled aluminium potline will mean production will be reduced until next April.
Despite this, Blenkiron says the decision to cut output validates the hard work that went into negotiating the agreements signed in May. These pledged to keep the smelter open until 2044, and were based on new electricity supply contracts signed with Meridian and its minority partner, Contact Energy.
The smelter gets paid for agreeing to cut power useage in principle, and gets a further payment if an actual cut is required.
Energy security getting more difficult
The smelter’s pledge came within days of the latest Security of Supply Assessment (SOSA) from Transpower, which repeated earlier suggestions that energy security was getting more difficult.
“South Island energy security over the 10-year horizon has worsened….due to a significantly higher demand forecast, no South Island generation projects reaching the completed or committed stage, and some South Island generation projects dropping out of the future pipeline,” wrote Transpower.
The company was speaking it in its role as the so-called system operator, which oversees the economics and technicalities of the entire electricity mechanism. That is in addition to its job as controller of the National Grid.
“New North Island capacity supply is required more urgently…..a key reason for this is that the supply pipeline is primarily made up of intermittent generation, which makes a lower contribution to peak capacity than do controllable power system resources,” Transpower wrote.
This document repeats the familiar argument, that when the wind doesn’t blow and the rain doesn’t fall, renewable electricity must be augmented from other sources, chiefly the burning of fossil fuel. Repeated findings that New Zealand is running short of gas has prompted greater use of carbon-intensive coal in its place to fill this gap.
In matching information, the electricity consultancy, Energy Link, reports falling inflows into New Zealand’s biggest complex of hydro power plants. These are the Waitaki River set of stations, as well as Lake Taupo, which is the source of water for eight North Island dams on the Waikato River.
Transpower says these problems must be faced up to.
“We have been calling for some time for a step-change in investment in flexible power system resources like fast-start peaking plant, grid-scale batteries and demand response,” the company says.
Along with the lower supply of electricity were higher prices, which passed $400 a mewawatt hour, up from the mid 300s a week earlier.
*Listen to Bardsley in an episode of our Of Interest podcast here; Could a pumped hydro scheme in Otago free NZ from fossil fueled electricity & help enable a green transition?
87 Comments
Bardsley has my full respect - compared the the 3-clown Circus, he's in another league entirely. They are looking silly, and will look sillier before this plays fully out.
But there is a bigger question, one avoided by Eric. Yes, Onslow makes entire sense IF WE ARE TO MAINTAIN BAU, BEYOND FOSSIL ENERGY.
But if we cannot? Because we cannot, according to my research
https://open.umn.edu/opentextbooks/textbooks/980
That question has never been answered, because it has never been asked.
"Yes, Onslow makes entire sense IF WE ARE TO MAINTAIN BAU, BEYOND FOSSIL ENERGY. "
Id suggest the greatest benefit of Onslow (or a similar scheme) is not that it will maintain BAU but rather it may provide a more controlled path away from the certainty of a demise of BAU.....certainly it offers more chance of that than any other proposal I have seen.
Spoke to a relative in Melbourne on the weekend. They were at the dry cleaners, power had been out for two days. Apparently this is happening monthly in their neighbourhood.
Australia’s transmission network is one of the oldest and longest in the world. As coal stations close and more renewable energy is built, the task of upgrading the system becomes even more pressing. So formidable is the challenge, it’s one of the biggest roadblocks Australia faces in reaching its crucial goal of net-zero emissions by 2050.
...
Australia's energy infrastructure, which has been supported by its aging coal-fired power plants, is having difficulty keeping up. Grid instability and blackouts are also being caused by the intermittent nature of renewable energy and the lack of adequate storage solutions.
One important factor of these difficulties is the underinvestment in energy infrastructure. Australia has not made enough investments in its energy infrastructure. This is despite being the world's largest exporter of coal and liquefied natural gas. The cost of building energy infrastructure in Australia in the 2022 fiscal year came to about 5.4 billion Australian dollars. It was higher than the year before but still insufficient to meet the rising demand.
Top issues from Aussies I speak to:
- immigration (theirs is still being pumped hard)
- crappy infrastructure
- house prices are still spiralling out of control
- if you go to a viewing for a rental, there will be 50 other groups going through.
So basically the same as NZ, but likely worse.
no its worse here
Property Investor Insights
Each month in conjunction with Crockers Property Management, I survey residential property investors to gauge how they are seeing the market and what their plans are. This month the results show the following main things.the pace of growth in rent rises sought by landlords continues to slow.
- Finding good tenants has become the hardest since mid-2022.
- Existing investors remain net sellers of property.
- For the first time on record more investors feel bank willingness to lend is improving than say it is worsening.
I'm sometimes dubious of when they say good tenants. I've seen what bad tenants do to places, but It seems more so today that since the 90's, with housing seen more and more as a speculative asset than a home, there are
- Less landlords allowing pets
- Expectations that a house will be left in the same state it was entered, not giving an inch on general wear and tear from occupancy
The reality is you are housing humans, they may want a pet, or the carpet may fray over time from use if it is cheap carpet etc. Sadly the reality is that many who are more realistic get ruined by one bad tenant and then only pick the perfect tenants moving forwards.
The vision and leadership is decided by the populace.
If for instance, we had a political party who came out and said "in order to secure reliable electricity for the next 50 years, we can do it, but y'awl got to pay $1500 more a year on your power bill", what do you reckon their odds are of successfully gaining office?
but y'awl got to pay $1500 more a year on your power bill
Where'd you get that number?
There is a thing called regulation. It's not as if the market here is returning poor profits to its shareholders. All a matter of who invests the necessary capital and how the regulatory environment around that is structured.
Plucked purely out of thin air. I don't actually know what a realistic figure is to secure and maintain the extra power generation and storage we're projected to need. I assumed around a hundred billion dollars and divided it by the number of households. Super crude.
Regulation doesn't preclude consumers from having to wear the costs of additional capital expenditure. At the moment, we're being given "adequate", but "amazing with loads of spare capacity" will require a significant step up in funding.
Ditto basically all of our infrastructure.
There's always a bill the consumer (or resident or citizen) picks up.
You either pay for it via direct billing from the supplier.
Or via state instruments like taxation, levies, debt, or opportunity costs. Or just pass it down to the next generation to pay for.
We can have whatever we want, we just have to pay for it.
The 'local loop' is already unbundled. Anyone can sell power to customers over the local lines companies.
At best the analogy with gentailers would be more like spark owning the retail business and also the southern cross cable. But really the analogy doesn't work
It was too big, at the wrong end of the country.And it did not add to renewable generation. But I do think a mini Onslow should go ahead, upgrading the existing dam, and Nevis river hydros.
Demand management, coupled with more solar is the fastest and cheapest answer. Unfortunately, it seems Simeon Brown is in cohorts of the fossil fuel lobby, so much so they didn't provide an incoming minister brief to him, he already knew their views that came with the donations.
The known cost of the scheme was alarming in itself but even more so was the unknown cost(s.) Where, how was the money to be found by any government? Or perhaps the land/lake should be leased to private industry, let them build it all up as required, and then charge for its output. Not exactly anyone queuing up for that as an investment either is there.
No one has a clue how much pumped hydro will cost or how much real benefit will be "generated"
Cf. OZ
https://www.abc.net.au/news/2023-10-23/snowy-hydro-sinkhole-toxic-gas-t…
https://www.abc.net.au/news/2024-05-22/tunnel-boring-machine-florence-s…
Far better option to reclaim Manapouri for NZ & add NI transmission...oh, sorry
Switching off the smelter doesn't solve the same problem as Onslow. It adds a whole bunch of baseload but very little storage. Onslow adds no additional generation, but an incredible amount of storage (I think it's equivalent to putting about 100 Tesla powerwalls in every household in NZ). That means you can smooth out other very cheap, but intermittent, generation.
The NZ Battery team at MBIE determined, on the basis of a long record of past hydro lake inflows, that there needed to be 3-5 TWh of additional energy storage capacity. That could be achieved from the Onslow basin. Pumped storage schemes are net energy users of course, but Onslow would add to renewable generation indirectly by providing a market floor price for wind and solar, giving additional economic incentive for new solar and wind power schemes - as noted in the Kelly report provided by the Parliamentary Commissioner for the Environment.
It's useful to have Onslow in the South Island because that's where the main hydro stations are located. Getting a lot of South Island hydro power north in wet times to a hypothetical North Island Onslow could be difficult with the HVDC bottleneck. There will also be South Island dry times when sometimes power has to be sent south from the North Island (as opposed to the usual northward transfer), which could be avoided if Onslow was operational. With respect to this, the text below is pasted from today's (23/7) release of "Weekly Market Movements" from Transpower.
HVDC flow was predominantly southward last week and during the weekend with
some periods of northward flow during daytime. The flows reflect limited inflows to
South Island hydro catchments and slightly lower demand in the North Island. In
total, 23 GWh was sent south and 7 GWh was sent north last week.
To suggest that an Onslow now would have cured everything is so wrong in my view. Because to have filled it up, 'surplus' water/ gas/ coal/ geothermal would all have had to be used to fill the damn thing up. If there is such a thing. (Given that it doesn't rain at Onslow very much).
So it would have made things worse in order to make a useful contribution.
The assumption is that there is a surplus of power available to fill it up. Alas, cheap power at night would instantaneously become not cheap. Which would make charging cars expensive. All sorts of unintended consequences.
Pumped storage Is a parasite.
The idea in the article was to make the point that it was unfortunate that the detailed business case report by MBIE for dry year options (the Onslow scheme and the "portfolio" scheme) was cancelled by the present government before it could be completed. The business case comparison of the two schemes would have been published about now (if there had been no change in government). When all the respective costs and benefits had been taken into account, one or other of the schemes might have gone further, or maybe both would have been rejected. My plug was not for Onslow, but for completion of the report so we would know more about the costs and benefits of both in the long view.
With respect to the issue of surplus power for pumped storage, that would come from reduced wind spill and reduced water spill. Over a few wet years, the Waitaki scheme can lose as much energy from spill as the energy storage capacity of the Onslow basin. If the Onslow scheme went ahead, by the time of first pumping there will be significant wind energy generation capacity in New Zealand. That means even more energy would be lost at times when the hydro lakes are spilling because wind spill would be added to water spill without anywhere to store the energy. Onslow would be thus utilising energy that otherwise would be lost - and giving some extra money to the wind and hydro generators in the process.
Onslow would fill to average operating level over a number of years by increments when the conditions favoured pumping. In the process, sometimes its water level will drop back when prices favoured generating. It does not require to be "full" before it can become operational. Its pumped storage function would start as soon as the water level rose above the minimum operating level, although its full dry year backup potential would require higher water levels.
Until quite recently, the NZ Battery web page contained a large amount of text that discussed the work they had done over the years relating to dry years. Then suddenly it all vanished, leaving only a list of reports for download, without any context. It would be nice if somebody had taken a copy of the old web page before it was cut, so that it could then still be available to the public.
This is a brief e-news to inform you that a large number of documents produced for the NZ Battery Project are now available on the webpage below.
A further bundle of documents is still being prepared for publishing and will also be added to this webpage in the coming months. We will issue a final NZ Battery Project E-news to let you know when these documents are available.
All information held by MBIE on the NZ Battery Project investigations will be retained in accordance with MBIE’s records management policy, as is consistent with the Public Records Act 2005.
MBIE stopped investigations into a pumped hydro scheme at Lake Onslow late last year. However our ongoing and wider electricity security work programme includes continuing to consider the question of security of supply and the need for long-duration energy storage.
Ngā mihi
Energy Markets branch
Ministry of Business, Innovation and Employment
I wonder if this will turn into a similar narrative to the ferry situation, only far more consequential. In the rush to score political points, the coalition have cast side previous plans and now have to start virtually from scratch, meaning years of delay.
If their answer is more thermal backup generation they need to come out and say this, and may need to build and run it themselves. The gentailers are trying to distance themselves from thermal as much as possible - Contact aiming to close their remaining plants, and Genesis trying to share the pain of running Huntley with other companies.
I don't think it's a conspiracy, I think it's very obvious from reading GNE and CEN market releases. The Gentailers don't want to run thermal - it's bad for business, carbon prices are likely to increase, and it's terrible PR. It makes them an ESG target.
CEN are aiming to decommission their thermal generation, and have already started to do so. Both CEN and GNE were trying to push for 'ThermalCo' to take the thermal generation out of their hands (for example, https://contact.co.nz/aboutus/media-centre/2021/11/15/thermal-co-enabli…). Now that has failed, GNE are trying to share the burden of running Huntley by contracting it out.
The gentailers don't want thermal generation. If the government's big plan is to use thermal to make up for gaps in intermittent generation, they will need to make some serious changes and quite possibly build and run it themselves. Huntley can do part of the job, but it can't be both a peaker and a dry year solution.
Agreed. Huntly should be a dry year solution as it currently is doing. What, in my opinion, is overlooked in the discussion is to develop Huntly into burning torrified pallets. According to a recent press release from Gisborne council, about 1.4M ton of forestry slash and wood debris has come down their hills. Through a torrefaction process that 1.4M ton could be converted to about 350000 tons of torrified pallets which has about the same energy density as coal but reduces the CO2 emitted by about 85%. But torrefied pallets are almost 3 times as expensive as thermal coal. A log export levy of 10$/ton should be able to close that gap.
Meridian and others have had hedge contracts with Genesis for many many years to have access to Huntly's generation when required.
These companies have been doing some greenwashing. Dirty birdies...
They did this so that they did not have to pay the huge spot market price for Huntlys power when it was required, in order to match their retail positions.
When the lakes are spilling they would be generating full bore. Day and night.
If wind is being 'spilled' then maybe too much wind has been installed in a particular area and maybe there are transmission constraints (incl HVDC). Or maybe the number of EVs has not increased as much as anticipated. ie All sorts of other deficiencies.
The market is incredibly complex and the generators will make investment mistakes.....
Power can only be generated, from whatever source, just to the extent of contributing to meeting the power demand at the time.
Lost generating opportunity, as arises in spill situations, is not good for anyone. The useful thing about the Onslow scheme is that its size enables handling of South Island wet years, even though it is most often spoken of in terms of dry years. When the South Island hydro lakes are high, the wholesale power price is likely to be low and Onslow will be a purchaser of up to 1000 MW of power. That will be supplied by water released from the hydro lakes to generate the power for pumping. That is, with Onslow in operation the hydro lakes will be less often near their maximum levels. So when significant sudden river inflows happen, there is more chance that there will be space in the lakes to hold them - as opposed to spilling from the lakes and then over all the downstream dams. In this way Onslow will increase the mean power output of the Waitaki hydro scheme, even though spill years are infrequent.
The dominant power transfer through the HVDC is from the South Island to the North Island. This could lead to spill if there was an extended HVDC fault and the lakes were already high. That would happen rarely but Onslow, being in the South Island, would be a ready purchaser of power in that situation.
On the smaller time scale, the Onslow scheme could also operate in support of firming wind power and reducing wind spill situations. Because it can both pump and generate, it would have a total of 2000 MW of firming capability for wind.
Lots of ifs in this. But its true that you need to use water up prior to a big melt or downpour.
To have a role in both dry year and daily firming. Well in terms of Harry Callahan: "whats it going to be punk...."
And lets not forget that by pumping and then later generating, its losses would be massive.
Onslow could do both daily firming and dry year reserve with no difficulty. Firming involves repeat sequences of pumping, doing nothing, and generating. There is no downward trend in the upper reservoir water level as a consequence.
Pumped storage schemes are actually quite efficient in general - with alternating pumping and generating. Round trip efficiencies can be as high as 80%. The absolute energy loss increases of course with the number of cycles. Then it becomes a question of economics - making enough income from the price difference to offset the energy loss. That's how most of the many pumped storage schemes work around the world - they have frequent cycles but limited storage.
"....There is no downward trend in the upper reservoir water level as a consequence."
It all depends on how much kWhrs of power is required to do such firming.
And if what you say is true, then maybe it is not filling up either so it would not be able to provide a dry winter of backup power. Hence my Harry Callahan line.
Sorry to be the devils advocate in all this. You are right in that by halting the study we will never know now.
But I have responded because I wanted to point out that there is a huge amount of assumptions to be made in such a study. Many of which would be hard to justify if challenged.
After having run SPD , E market offer and such like in the past, my gut feel is that Onslow would not have been cost effective. Not even close compared to alternatives. My favourite would be new hydro (ie not a parasite), new transmission and possibly photovoltaic or geothermal But with some of those latter ones, care would be needed in what sort of lifespan you would get out of them. Gas thermal is really cheap if gas is available and the CO2 penalties not ridiculously high. But again so many assumptions are required its not funny.....
New renewables will happen anyway, but having more power generation is no substitute for having more energy storage capacity. Also, particular care is needed with new hydro. In a dry year, that could just lead to a greater impact because there could be even more power stations producing minimal power. It's probably unlikely that the New Zealand public would ever accept another major power station in a river valley. The abandoned North bank scheme (lower Waitaki) and the Beaumont scheme (lower Clutha) are indicative of that.
I'm sure you're right in saying Onslow would not be cost effective, in the sense that it would take a very large number of years to recover the construction cost by buying power cheaply and selling it later at a higher price. However, it needs to be evaluated for its multi-purpose uses, including water resources and supporting new wind power through its fast-response capability. It would also aid scheduling temporary closures in the existing power stations. It might still be not cost effective compared to alternatives even then - but hopefully the evaluations and comparisons will eventually get done.
I don't think short-term firming implies that there will be a tendency for water volumes released when generating to be greater than water volumes raised into the upper reservoir went pumping. The initial fill, or recovery after a dry winter, would be by increments as mentioned previously.
Plenty of fanciful comments on what to do. An initial 429 pg report on Onslow published around 31Mar23, New Zealand Battery Project: Progressing to the Next Phase.
pg11
A 2.7TWh, 570MW pumped hydro solution in the North Island was also identified.
However, insufficient information was available to confirm whether it is acceptable and feasible.
******** This option was removed from further consideration at this time pending further engagement with iwi. ************
Pending that engagement, further work would be required to better understand how it would
interact with existing hydro schemes, and so its real economic potential.
I'm thankful it has been halted.
added later from above report
pg 18
Subject to iwi engagement, the next steps for the North Island pumped hydro option are
to determine whether it could have sufficient economic benefit to be worth investigating further.
The NZ Battery project will require a focus on building strong relationships with iwi / Māori,
as well as engagement with other stakeholders."
Far too big. We would need another 2GW of backup generation on top of that too cover planned downtime, and always ready to flick the switch to start generating. Otherwise any minor fault with your nuclear plant or the lines leading to it means huge blackouts. That backup is hugely expensive, and would probably have to look like another couple of Huntleys.
Smaller scale ~400MW SMRs could be a good fit once they are proven.
Just do a 10km x 10km floating solar in the middle of lake Taupo. Enough juice for 1.75M households or 90% of the country. Use lake Taupo as the battery.
You'll need some biggish pontoons to float it over the 1.5m worst case swell, but pretty well insulated from earthquakes. Just the odd eruption every 10 million years.
Using Taupo as the battery means letting the Waikato run dry on sunny days, could be a tough ecological sell. Even then, the Waikato system generates about 13% of the country's power supply - I suspect it's not big enough to fully balance out such a huge, entirely correlated, power source.
Now, if you were floating a solar array on the lake generated by the Onslow project....
This highlights ( to me at least) New Zealands fundamental problem:
The current decision making generation 35-60 year olds will not accept anything that might cost them financially, if the reward for the decision is benefitting the following generations and not them (us).......
Im not sure if im explaining myself right , but unless Nz politicians starts making uncomfortable decision that our generation wont see any reward for, the future of this country is grim for the ones that follow us ....
( in my broken english/danish) translation)
...the electricity consultancy, Energy Link, reports falling inflows into New Zealand’s biggest complex of hydro power plants. These are the Waitaki River set of stations...
I suggest that a review over Meridian on water management would be useful. Locals point to rivers running flat out and low and behold lake levels are at historic lows...
Again - a failure of the peaking plants and operators to do their job. Gas is no longer reliable and coal has been left to wither on the vine, noting it’s the dirtiest & most expensive solution.
Our hydro is great but it relies on snow melt and only has 6 weeks capacity from full to empty.
We can criticise Australia for having crappy transmission infrastructure but they have wholeheartedly embraced wind and solar. The % change in their use of renewables is quite impressive.
The $4 billion dog is still a dog at $16 billion.
Ten fatal flaws with the Lake Onslow concept
https://www.energywatch.org.nz/issues/EW85_7-2022.pdf
Summary from a previous edition:
• The scale of the original Lake Onslow scheme is 10 times larger than is needed to address the so-called “dry-year” problem.
• The scope of the project has changed: -
o Level reduced from 800 m to 760 m.
o Tunnel increased from 15 km to 24 km
o Soil removal from 27 km2 added
• The Teviot Valley dam would be 1.5 km long making it the second [longest] hydro dam in the world after the Three Gorges dam in China.
• The increased water losses due to seepage and evaporation would require permanent pumping to maintain the Lake Onslow level.
• The round-trip efficiency would be <60%
• The cost of electricity to fill Lake Onslow would exceed the revenue from electricity sales in a low-hydro year. So, there is no economic rationale to proceed.
• Filling Lake Onslow would create an electricity shortage in New Zealand of greater magnitude than the “dry-year” problem.
• The NZ Battery Project should abandon the Lake Onslow concept forthwith without the need to proceed with re-estimating the capital cost of the ~$4 billion project.
Those interested might also have a look at:
One of the unusual aspects of public discussions about the Onslow scheme is that it has given rise to what might be called "tabloid science", where individuals feel they need to go to some effort to "prove" that the scheme concept is totally flawed. They construct posts full of unreferenced assertions, which are then cited by others as if they were facts.
Just to note a few from the above:
"Round trip efficiency < 60%" This number is made up. It might just has well be stated as <40%. The NZ Battery investigators estimated the efficiency at 70%. In the first MSc study of the Onslow scheme I instructed the student to simulate at an impossibly low efficiency of 60% as an academic exercise. Maybe this was the origin of the 60% idea.
"Tunnel increased from 15 km to 24 km". That would only apply if Lake Roxburgh was the lower reservoir. The drilling investigations indicated a Clutha River connection was under active considerations - a tunnel length of about 16 km.
"It would be the second longest hydro dam in the world" For much of its length the Teviot dam would be a low buffer dam. It would be nothing like the Benmore dam, for example.
There is no point in going on personal crusades either for or against the Onslow scheme. There needs to be time taken to properly evaluate the scheme against alternatives - which may or may not result in the scheme being rejected when all the costs and benefits are taken into account. In this regard, it is unfortunate that the new government stopped the detailed business case report on the various options before it could be completed.
The Sustainable Energy Forum seem to have some reasonable questions about the project, which is sorely lacking from the lapdog media. Hardly a personal crusade. Given the Snowy River and Clyde Dam cost blow outs the more questions the better.
"70% round trip efficiency for pumped storage is the best that can be expected for a night-day pumped storage scheme. The aim of the Lake Onslow scheme is to store energy for at least 6 months and maybe for a few years.
In EW84, stored water losses were estimated as 2.5 m3/s (3.2 mm/day) by evaporation and 0.8 m3/s by migration of groundwater, i.e. 107 million m3 of losses per year. The large generation head of 600 metres, would give a minimum loss of 175 GWh/year of potential energy, that is 4.2% of the stored potential energy each year. The losses due to groundwater flows could be much greater.
Dam length
The rolling moorland terrain, as shown in the picture on Page 1, is not well suited to impounding a reservoir. Raising the water level of Lake Onslow from 700 metres to 760 metres above sea level would require a 1.5 km long dam to be built. That is three times longer than the Clyde dam and 2/3 of the length of the giant Three Gorges Dam on the Yangtze River in China. This picture of the Cochiti earth dam in New Mexico gives an indication of the type of dam that would be required to impound Lake Onslow."
It is of course good to raise questions about any major project - that's the way the original Lake Manapouri scheme was halted. However, it's quite different to present risky assertions. Presumably the referenced EW84 did not go through a peer review process. Groundwater loss rates are always difficult to estimate and depend critically on the specification of hydraulic conductivity. The referenced 3.2 mm per day of evaporation loss translates to about 1.2 metres annually. This is an over-estimate because NIWA direct measurement of Lake Onslow evaporation was less than 1 metre per year and not much greater than annual rainfall.
Some Lake Onslow water loss would of course still be a contributing factor reducing scheme efficiency, if it was built. That is, to maintain the Teviot River mean discharge there would need to be, on average, a little more water pumped up than goes back down. However, the aim of the scheme is not to "store water for at least 6 months or a year", as if it was being held in reserve and doing nothing except slowly losing water. The scheme would be in continuous operation, in particular playing a firming role for the anticipated increased wind generation to come, and with seasonal generation - mostly in winter. The question then becomes one of economics - will the price differences offset the decrease in efficiency? If the Onslow investigations re-started, it would certainly be desirable to get an improved idea of the new water balance.
No argument about the cost blowout risk. It seems a feature of many big projects. However, each project is different. The often-referenced cost blowout of Snowy 2.0 is not because it is a pumped storage scheme, but because it is a civil engineering project with tunnels through variable geology. From the other viewpoint, finding a big pumped storage scheme somewhere in the world that was constructed under budget could not be used as evidence in favour of the Onslow scheme.
Actually, in terms of energy storage measure Snowy 2.0 does not give very good value for money. It could generate 2000 MW for two weeks. Onslow could generate 1000 MW for 6 months.
A more reasoned response than labelling it tabloid or a personal crusade. Speaking of personal crusades is there a bit of projection here?
"The Lake Onslow concept was first proposed in a short paper to the New Zealand Hydrological Society in 2005 titled “Note on the pumped
storage potential of the Onslow-Manorburn depression, New Zealand” by W. E. Bardsley Dept. of Earth Sciences, University of Waikato.1"
Why presume EW84 at all? Why not just read it? Though I am pretty sure you have read it!
"This analysis of the dry-year situation suggests that the multi-million dollar “New Zealand Battery” study is using a sledgehammer to crack a nut. That study appears founded on the premise that the Lake Onslow scheme is the only way to future-proof electricity supply in NZ. This issue of EW challenges that premise."
Unfortunately there is a lot of tabloid science around on all sorts of topics. I have issue more with the idea of that than anything personal with anyone involved. What happens is that an original false assertion gets referenced by somebody.. then that gets referenced again.. and before long it gets to the illusion of an accepted fact. I never read that sort of material in principle and have not seen EW84 - whatever it is.
As an example of setting up a false assertion, consider the reference to my original 2005 short note about Onslow:
"That study appears founded on the premise that the Lake Onslow scheme is the only way to future-proof electricity supply in NZ."
and compare that with the text in the Conclusion of that note:
"However, it is left an open question as to whether it would be viable within the current grid system in the absence of a complete analysis of economic,
environmental, and engineering aspects."
In other words - it just might be worth looking at further but it's too soon to say.
The weird thing is, after all these years and all the subsequent investigations, we are frustratingly in the same situation because the present government has prevented completion of the final business report looking at the Onslow scheme and its potential alternatives. As noted earlier, I'm not on a crusade for Onslow or any specific alternative. But a lot of taxpayer money has been spent looking at dry year options to date and we should be entitled to see the report come to final completion so we have as much information as possible. That report would have included both biomass and reserve geothermal alternatives.
$16 billion would be better spent on a few of these babies. Electricity, process heat, ammonia for fertiliser/fuel... Far more useful than a dam.
"In a global first, researchers at Tsinghua University in China have successfully demonstrated a meltdown-proof nuclear fission reactor.The twin reactor design can generate 105 MW of power each and has been in the works since 2016
...The reactor began commercial operation only in December 2023. To demonstrate that it could cool itself down without an external source, the team shut down both modules when it was running at full power and began tracking temperature movements inside the reactor.
As expected, the reactors cooled down naturally and reached a stable temperature 35 hours after they were shut down."
https://interestingengineering.com/energy/meltdown-proof-nuclear-reactor
For $16 billion we could by an aircraft carrier or some nuclear subs complete with reactors. The decision on Onslow was still 4-5 years away with ten years to build (much longer if going by Clyde dam). Get hold of the Koreans - they can have a couple of reactors in for you by then.
https://newsroom.co.nz/2023/05/18/compo-in-the-wind-if-onslow-plan-proc…
https://apnews.com/article/czech-nuclear-rector-dukovany-edf-khnp-c6a84…
Earl , I have wondered on a mini Onslow scheme , Using expanded Teviot River hydro scheme tunnels and dams/ ponds to pump up in stages . Any ideas on the feasibility of this?
Also pumping from west coast headwaters , over / through the alps to the existing upper hydro lakes . I have also wondered about using the Otira rail tunnel ( building a channel in the base , under the rails , but their is no hydro lake that close to this . Probably more suited to irrigation.
Hi solarb,
People often raise the possibility of a sequence of river hydro dams operating in reverse. It's complicated because it's trying to operate a hydro power scheme and a pumped storage scheme at the same time. Also there would be efficiency losses at each dam. I don't know of anywhere in the world that operates a pumped storage cascade.
Eastward water transfer from the wet west coast is raised from time to time, but that's a different question to increasing energy storage capacity.
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