Power shares

[gains]

I think Onslow would make a lot more sense if NZ had a power linkage to Australia similar to the Australia-Asia power link that is in development now. They have heaps of solar energy generation and huge future potential solar capacity expansion, but lack energy storage (power prices were going negative during the day in solar heavy states). Onslows cost per kwh of storage is compelling but I do wonder if we need to have so much storage. Onslows purpose is also partially political (to combat climate change) and helping AUS with their storage problem would further this goal given something like 0.6% of global emissions are from the AUS electricity network.

Interestingly enough, an HVDC link to Aussie would reduce the need for Onslow as it would unlock Australian power generation to NZ. Most notably, solar for NZ peak demand. Because of the time lag, you can still have major solar farms generating electricity while NZ no longer has sunshine hours to generate. It would also enable nuclear power, the greatest risk with nuclear to NZ is tectonic instability which Australia could provide. Ultimately, it would mean generation diversification over completely different weather systems which becomes important as we become more reliant on wind and solar.

The down side to an HVDC link to Australia is the transmission line losses. I got curious one day and calculated the losses and over the distance it was something in the magnitude of 1/3 of the total power transmitted would be lost. Of course, this has its assumptions to make that calculation on the back of a napkin but it's a ball park figure. Transmission losses are also a concern with Lake Onslow, however the distance and therefore the losses are much less.

In response to the posted article:

4. Pumped hydro is one of the most efficient means for energy storage with 80%-90% full cycle efficiency. When you compare it to batteries, it's cheap. Someone on this thread calculated that the capacity which Onslow would provide in energy storage would be something in the magnitude of trillions of dollars if built from lithium ion batteries. NZ is unique in the fact the most viable pumped hydro project in the country is Onslow, the downside is the share scale of the project. A notable comparison would be electric mountain if you're interested. Further to xafalcon comment, it assumes the wind always blows and the sun shines when we need it.

5. The opposite is actually true. New renewable generation is encouraged by Onslow as it promises that when the winds blowing and the suns shining, there will be a demand. Minimal to zero curtailment would be required. It provides a pricing floor, ie Onslow starts pumping up hill when the price get below $x and pumps down hill when price goes above $y. 

6. Hydrogen generation will be a fantastic load for the power grid. However, hydrogen for long term storage, is inefficient and not worth it - a pumped hydro system is a much preferred method. 

7. Refer to comment 4.

8. This again assumes we can generate enough power at all times. Onslows biggest achievement is when our whole power generation capacity is weather, the lights can still stay on. It just smooths out the peaks and troughs of demand vs generation

[kiora]

It will be interesting if this works & over what distances & loads???
"The Emrod technology works by utilising electromagnetic waves to safely and efficiently transmit energy wirelessly over vast distances. The prototype received some government funding and was designed and built in Auckland in cooperation with Callaghan Innovation."
https://www.powerengineeringint.com/...n%20Innovation.

[RTM]

A company in the US, SO, is having all sorts of problems getting a nuclear power plant completed.

https://www.reuters.com/business/ene...ts-2022-02-17/

I wonder how we would get on ? Maybe a tunneling or piping project, eg Lake Onslow, might be best ?

[Snoopy]

The Majeed thesis addresses the economics and overcomes the common fallacy of this just being a dry year storage facility.

Consider Onslow as being like a thermal power that has to buy its fuel. Combined cycle thermal plants like at Huntly or Stratford also have to buy their gas, but they buy it as they burn it. The older Rankine units at Huntly have to buy coal in advance just as Onslow would have to buy water in advance. The cost of gas to the CCGT plant varies but is often around $7 per GJ, and they need 8 GJ to generate 1 MWh of electricity. Thus their fuel cost alone is around $55 per MWh add on other OPEX costs and their SRMC is close to $70 per MWh. Onslow would need to buy 1.3 MWh of energy to pump enough water uphill to generate 1 MWh of energy back into to grid. The OPEX costs for hydro stations is quite low and usually less than $3 per MWh. So to be able to offer at an SRMC of $70 MWh it would need to buy energy at less than $51 per MWh. So already we see the initial bids and offers so as to align with the current market. First tranche of bids at $50 and first tranche of offers at $70.

The current market rules allow for bids to be made in up to 10 tranches, so 10 machines would effectively mean bidding into the market with 1 machine per tranche. Using that $50 figure arrived at earlier for tranche 1, a typical bid may be $50 for 120 MW, $45 for 120 MW, $40 for 120 MW etc until the last machine would would be $5 for 120 MW. As bids are cumulative then a nodal price of $30 would see a load dispatch of 600 MW, and would see a gain in storage in Lake Onslow of 461 MWh at a cost of $18,000.

The rules for generation are not quite so flexible and only allow for 5 offer tranches. Ideally the rules would be changed to allow for 10 tranches, the same as for bids, but for this calculation lets assume there is no change in the rules. Using the $70 offer figure for tranche 1 arrived at earlier a typical offer would be $70 for 105 MW, $80 for 105 MW, $100 for 105 MW, $120 for 210 MW, and $140 for 675 MW (The reason for desiring a rule change becomes obvious). The 105 MW figure is chosen as this would be close to the most efficient operating point for a 120 MW machine. As offers are cumulative a nodal price of $100 would see a dispatch of 315 MW for a loss of storage of 315 MWh per hour and a revenue of $31,500.

Thus Onslow is not just dry year storage, but is like a fast start thermal station that can buffer wind generation. Because of its swing from full demand to full load it could buffer an additional 2400 MW of installed wind capacity.

Very interesting article on Onslow here.

https://www.newsroom.co.nz/trade-off...-nzs-lights-on

And the comments below the article are possibly even more interesting than the article itself. Here is a fraction of one comment from Ciaran Keogh of Environmental Consultants Otago Ltd.

"If we need to store more water for dry years, we can do it simply by maintaining an emergency buffer in the existing headwater lakes. That would cost nothing and have a better result because it would not consume any electricity."

"How many wind turbines could be built for $4billion? Working on a cost or $2Million per megawatt of capacity that equates to two gigawatts of generating capacity, all of which could be built in the North Island closest to the source of demand."

"The biggest flaw in the pumped storage idea is that it contains the expectation that dry spells will alternate with wet years but that is not how the climate works. The Interdecadal Pacific Oscillation causes a long-term drier and wetter phases, particularly in the South Island. NIWA notes in an item on its website titled “Long-term fluctuations in river flow conditions linked to the Interdecadal Pacific Oscillation” Flow data from 2000 onwards in the South Island support the idea that flows in those rivers are lower during the negative phase of the IPO. The data suggest that the post-2000 reduction in flow has been of the order of 10%. It is unclear for how long the IPO will remain negative, but previous IPO phases have lasted 20-30 years, so the current negative phase may last another 10-20 years. Pumped storage might just make the problem worse – not only does it use more electricity than it produces but it will suffer exactly the same problem as the existing “batteries” in the system in the lakes at the head of the Waikato, Clutha and Waitaki. Dry years happen in a multiyear series so what happens in year two once the water in the “battery” is run down in the first dry year? Back to where we started but with less electricity and $4Billion poorer?"

SNOOPY

[Snoopy]

Very interesting article on Onslow here.

https://www.newsroom.co.nz/trade-off...-nzs-lights-on

And the comments below the article are possibly even more interesting than the article itself. Here is a fraction of one comment from Ciaran Keogh of Environmental Consultants Otago Ltd.

"If we need to store more water for dry years, we can do it simply by maintaining an emergency buffer in the existing headwater lakes. That would cost nothing and have a better result because it would not consume any electricity."

"How many wind turbines could be built for $4billion? Working on a cost or $2Million per megawatt of capacity that equates to two gigawatts of generating capacity, all of which could be built in the North Island closest to the source of demand."

"The biggest flaw in the pumped storage idea is that it contains the expectation that dry spells will alternate with wet years but that is not how the climate works. The Interdecadal Pacific Oscillation causes a long-term drier and wetter phases, particularly in the South Island. NIWA notes in an item on its website titled “Long-term fluctuations in river flow conditions linked to the Interdecadal Pacific Oscillation” Flow data from 2000 onwards in the South Island support the idea that flows in those rivers are lower during the negative phase of the IPO. The data suggest that the post-2000 reduction in flow has been of the order of 10%. It is unclear for how long the IPO will remain negative, but previous IPO phases have lasted 20-30 years, so the current negative phase may last another 10-20 years. Pumped storage might just make the problem worse – not only does it use more electricity than it produces but it will suffer exactly the same problem as the existing “batteries” in the system in the lakes at the head of the Waikato, Clutha and Waitaki. Dry years happen in a multiyear series so what happens in year two once the water in the “battery” is run down in the first dry year? Back to where we started but with less electricity and $4Billion poorer?"

I have spent some time on the Contact Energy thread looking at how a staggered price cap plan at Onslow might affect the profitability of Contact Energy. But there is a far more serious consequence of choosing the wrong price cap at Onslow that will affect the future viability of the entire electric power system.

The problem is that the construction of new power stations becomes viable as the future wholesale power prices rise. This is very apparent from the Mercury Energy Annual Reports. The Property Plant and Equipment section of these reports contains a section reporting on 'assets carried at fair value'. At Mercury, these 'fair value' changes reached an extreme in FY2021 when suddenly $938m worth of 'new assets' appeared on the balance sheet. In fact these 'new assets' were not new in the bricks and mortar sense. This astonishing amount of money 'came into being' in just one year, based solely on the revised future earning power of Mercury's legacy power generation assets.

To some observers, this $938m materialised out of 'thin air'. However it was based on a model that foresaw future wholesale energy price rises to a level of $74MWh to $180MWh. If Onslow reduces these high price expectations, then this so called 'thin air capital' (created from future energy price expectations) will disappear. And with it, so will the economics that makes the building of certain new power stations viable.

Therein lies the 'balancing problem' for Onslow. Make the power price cap too high, and consumers will continue to be ripped off by gentailers manipulating the wholesale power price market. But make the power price cap too low, and suddenly the economics of the much needed new renewable power stations no longer work. I.e. they will not be built! Therein lies the fine balance that 'the great NZ battery Project' (for which Onslow is the favoured front runner) must strike with their 'market intervention' power pricing.

SNOOPY

[winner69]

Apparently we going to be short of electricity today

[Jantar]

Apparently we going to be short of electricity today

We have already seen 5 minute prices spike to around $800 this morning. Final prices look like they may come out at around $500 for TP15.

https://www2.electricityinfo.co.nz/p...search_exclude=

[Getty]

Very interesting article on Onslow here.

https://www.newsroom.co.nz/trade-off...-nzs-lights-on

And the comments below the article are possibly even more interesting than the article itself. Here is a fraction of one comment from Ciaran Keogh of Environmental Consultants Otago Ltd.

"If we need to store more water for dry years, we can do it simply by maintaining an emergency buffer in the existing headwater lakes. That would cost nothing and have a better result because it would not consume any electricity."

"How many wind turbines could be built for $4billion? Working on a cost or $2Million per megawatt of capacity that equates to two gigawatts of generating capacity, all of which could be built in the North Island closest to the source of demand."

"The biggest flaw in the pumped storage idea is that it contains the expectation that dry spells will alternate with wet years but that is not how the climate works. The Interdecadal Pacific Oscillation causes a long-term drier and wetter phases, particularly in the South Island. NIWA notes in an item on its website titled “Long-term fluctuations in river flow conditions linked to the Interdecadal Pacific Oscillation” Flow data from 2000 onwards in the South Island support the idea that flows in those rivers are lower during the negative phase of the IPO. The data suggest that the post-2000 reduction in flow has been of the order of 10%. It is unclear for how long the IPO will remain negative, but previous IPO phases have lasted 20-30 years, so the current negative phase may last another 10-20 years. Pumped storage might just make the problem worse – not only does it use more electricity than it produces but it will suffer exactly the same problem as the existing “batteries” in the system in the lakes at the head of the Waikato, Clutha and Waitaki. Dry years happen in a multiyear series so what happens in year two once the water in the “battery” is run down in the first dry year? Back to where we started but with less electricity and $4Billion poorer?"

SNOOPY

Excellent post, showing cause and effect possibilities.

NZ doesn't need a white elephant.

Thanks for sharing this information.

[Snoopy]

Excellent post, showing cause and effect possibilities.

NZ doesn't need a white elephant.

Thanks for sharing this information.

I am not sure it is fair to call Onslow a 'white elephant'. Ciaran Keogh of Environmental Consultants Otago Ltd. thinks there are better solutions. But if we start producing hydrogen fuel in Southland, and Rio Tinto looks to keep the aluminium smelter going down there as well, suddenly we may not have the surplus of power down south that we thought we had. In such a circumstance, having a 'local battery', like Onslow, might be just the thing to have and be in just the right place.

Responding to this article by Dr Kevin E Trenberth

https://www.newsroom.co.nz/kevin-tre...431c1-97981709

Peter Olorenshaw (Architect) has a novel alternative solution based on the number of Nissan Leaf cars already 'installed; in New Zealand.

"And just on batteries - you may be forgetting the batteries we already have here in the form of our Nissan Leafs already set up for Vehicle to Grid operation. They may well be a useful way to store daytime summer solar power and I came across an Australian article. Below is the link to an article on this Vehicle to Grid technology just come to Australia may help out as a grid solar load balancing thing."

https://www.abc.net.au/news/science/...alia/100811130

"While of course we need to reduce our energy consumption and beware of just producing more energy to support our current lifestyles, the thing is that this uses what we’ve already got - these EVs sitting idle for 95% of the time. (And the thing is that Lithium battery chemistries in these EVs seems to be considerably different to other chemistries we may be more familiar with. It appears that the primary degradation in EV batteries is through simple calendar degradation, not number of cycles. In fact Flip. the Fleet found that the more EVs were drive, i.e. the more charges they have, the better condition their batteries were in. So for EV owners if there is no battery longevity downside in using your car battery for grid support and you charge them up at the very low nighttime rates and discharge at very high peak rates, being handsomely rewarded for doing so, why wouldn't you?)"

"The article laments that new EVs will have to be made compatible with V2G applications and that currently only Nissan Leafs and Misubishi Vehicles can do this - But we’ve got some 15,000 used Nissan Leafs here in NZ already, let alone new ones! - the trick is to have them plugged in when we have a solar surplus. Some will be at home during the day, some will be at peoples work places. It would of course need these trick wallboxes wherever the EV is parked most - be that work or home."

"And just how big is that battery capacity available? - if we assumed 10kWh* from 15,000 Nissan Leafs then that is 1,500MWh = about an hour and half of Huntly Power Station going flat out or 3 hours of Benmore station (largest hydro station after Manapouri). In comparison the much celebrated big Tesla grid battery in South Australia (which doesn’t use cars) is 200MWh - so we are talking about 7 times the amount of this celebrated big battery, just from our old Leafs around NZ."

"* The First Nissan Leafs that came out had 24kWh batteries, next model had 30kWh, New shape ones have 40-64kWh so assuming 10kWh from every Leaf is surely not too far out for this back of an envelope calculation."

However, I believe there is flaw in Peter Olorenshaw's calculation. V2G technology was first trumpeted with the second generation Nissan Leaf that started appearing around 2020. So I don't think all of those earlier Nissan Leaf's from 2010 to 2019, which make up the bulk of the NZ Nissan Leaf fleet, have this V2G technology fitted.

https://www.nissan.co.nz/about-nissa...australia.html

Tesla, with the number new vehicles that have appeared on NZ roads since the referenced Newsroom article, may be able to help. Officially Tesla do not promote V2G technology. However, according to this article:

https://electrek.co/2020/05/19/tesla...ging-features/

the hardware does exist within the more recent model 3 and model Y vehicles to make V2G use possible in the future.

SNOOPY

[xafalcon]

"And just how big is that battery capacity available? - if we assumed 10kWh* from 15,000 Nissan Leafs then that is 1,500MWh = about an hour and half of Huntly Power Station going flat out or 3 hours of Benmore station (largest hydro station after Manapouri). In comparison the much celebrated big Tesla grid battery in South Australia (which doesn’t use cars) is 200MWh - so we are talking about 7 times the amount of this celebrated big battery, just from our old Leafs

SNOOPY

Last time I checked, 15,000 x10 = 150,000 = 150MWh

Most Leafs in NZ only have 8-12 KWh of battery capacity remaining, and require a significant amount of this to act as a transport machine

Batteries degrade with cycles, time, usage, temperature

Say a leaf owner charges at $0.15/KWh, sells 5KWh at $0.30/KWh, with energy recovery of 85%, they make $0.63 before tax. Who would bother?

This V2G concept appears to work on paper but will not work in reality