Tiwai Point Smelter

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peejayw

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#268026 24-Feb-2020 14:46

I dont want to get into a discussion on EV v ICE, plenty of that already but I was just reading an article about the waste from Tiwai that was threatened by the recent flooding down there and it got me thinking about all that power being consumed by the smelter and the benefit to NZ.

It seems that the smelter uses about 13% of our electricity production and it is supplied at a considerable discount. The smelter uses 570MW and generates approx 500,000 tonnes of CO2 annually.

I dont know the maths but I wonder how many EV's could run on the power the smelter is using and what the reduction in CO2 would be from those vehicles. Also, what would it save the country in oil imports.

Maybe if that cheap power was used for vehicle charging that would be a no- or little-cost incentive to boost the uptake of EV's here, just a thought.

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#2426354 24-Feb-2020 14:56

Manapouri was built specifically for Tiwai. Pretty sure as it stands the electricity network in the south island isn't designed to put that power into the regular grid in any substantial capacity.

ShinyChrome

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#2426356 24-Feb-2020 14:57

Its been covered before in one thread or another on the subject, but the basic points are: 1) the infrastructure to redirect its power supply to the national grid doesn't exist and would require costly investment (in the hundreds of millions I think I have read previously); and 2) the impact to the local economy is not negligible in terms of revenue and jobs.

Yeah, it has an impact environmentally, but it's a complex issue and not as simple as just 1. turn it off 2. hook up the Leafs 3. Profit $$$

This article seems to be mostly on-point.

djtOtago

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#2426360 24-Feb-2020 15:05

The math (I think)

64 x 24kw Nissan Leafs full charging every day for 1 year =~ 570 MW of power.

So Smelter power would support 64 1st Gen Nissan Leafs fully re-charging everyday.

Obraik

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#2426361 24-Feb-2020 15:10

To be honest, the lack of power isn't a hinderance on the uptake of EVs in the country right now. I also wouldn't consider the cost of power as a hinderance either since it's significantly lower than that of petrol. I currently pay 11c/kWh on Meridian's EV plan. My Model 3 averages around 150Wh/km so that's around 2c/km vs around 21c/km using average fuel economy numbers.

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djtOtago

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#2426365 24-Feb-2020 15:15

From https://www.odt.co.nz/business/tiwai-closure-would-spur-transmission-spend-study

In a footnote to investors, the country's largest electricity retailer put an indicative cost of $600million and a timeframe of five to eight years to undertake the required upgrade work to enable transmission of South Island generation to the North Island.

KrazyKid

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#2426373 24-Feb-2020 15:39

djtOtago:

The math (I think)

64 x 24kw Nissan Leafs full charging every day for 1 year =~ 570 MW of power.

So Smelter power would support 64 1st Gen Nissan Leafs fully re-charging everyday.

That seems a bit wrong to me. My guess making some assumptions/approximations to keep life simple :

570 MW = 570,000 KW

570,000 divided by 24Kw = 23,750

A 24KW Leaf takes about 12hrs to fully charge at 8 Amp so if we lined them up nicely we can to 2 shifts :)

So Manapouri could fully recharge 47,500 Nissan Leafs every day if it wasn't being used by the smelter.

Saying that most Leaf's only let you use 22KW of battery, and many people only recharge there Leaf every second day or so don't treat these numbers as anything more than an interesting unit of measure.

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frankv

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#2426423 24-Feb-2020 15:57

ShinyChrome:

Its been covered before in one thread or another on the subject, but the basic points are: 1) the infrastructure to redirect its power supply to the national grid doesn't exist and would require costly investment (in the hundreds of millions I think I have read previously); and 2) the impact to the local economy is not negligible in terms of revenue and jobs.

This article seems to be mostly on-point.

Plus...

3) Tiwai Point uses electricity 24x7, which is one of the reasons why it's sold to them relatively cheaply. NZ's demand fluctuates, so without the smelter a fair amount of water would have to be spilled from Lake Manapouri without producing any electricity at all. But maybe power could be generated from Manapouri continuously, and the flow through other dams (e.g. Benmore) controlled to minimise water wastage.

4) Most of NZ's electricity demand is in the North Island, so the electricity generated at Manapouri would have to be put through the Cook Strait cable to be useful. And there are limitations on that (although I couldn't find what the limits are exactly, or how close we come to them already). But maybe upgrades to this are included in the $600M figure given in the article.

tripper1000

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#2426424 24-Feb-2020 15:57

The CO2 produced by Tiwai is an completely false and baseless argument designed to capitalise on trendy hot topics/peoples ignorance. Closing Tiwai will lead to a net increase in the worlds CO2 production.

Aluminium requires an enormous amount of electricity to refine. Tiwai is one of the greenest aluminium smelters in the world with 90% - 100% of it electricity coming from renewable resources. Most other smelters rely on fossil fuel powered generation.

If you really care about t he global environment, CO2, employment or the economy, then N.Z. should be building another 10 Manapori/Tiwai's and putting the grubby smelters out of business.

afe66

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#2426426 24-Feb-2020 16:00

djtOtago:
The math (I think)

64 x 24kw Nissan Leafs full charging every day for 1 year =~ 570 MW of power.

So Smelter power would support 64 1st Gen Nissan Leafs fully re-charging everyday.

Is it that simple though ?

Average electricity use per house per year in nz is more than 5000kWh (5MWh) so that would suggest Manapouri only supplies enough electricity for 100 houses using your approach...

tripper1000

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#2426429 24-Feb-2020 16:07

Tiwai getting power at cheap rates is also a deceptive/highly selective argument, focusing on the wholesale generation cost exclusively and totally ignoring the true cost including transmission costs.

Tiwai pays 14% of the transmission costs of the entire Transpower network despite using only ~200km of the network. (payback if they built their own pylons would be just a few years, so they weighing up how hard it will be to get permission to do so). This means they are subsidising the entire North Island as Auckland consumers pay the same/similar cost, despite using >1,000kms of network more. If Tiwai shuts down, your power bill WILL increase as the ~$67 million shortfall will be be charged to the remaining consumers.

frankv

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#2426432 24-Feb-2020 16:15

KrazyKid:

djtOtago:

The math (I think)

64 x 24kw Nissan Leafs full charging every day for 1 year =~ 570 MW of power.

So Smelter power would support 64 1st Gen Nissan Leafs fully re-charging everyday.

That seems a bit wrong to me. My guess making some assumptions/approximations to keep life simple :

570 MW = 570,000 KW

570,000 divided by 24Kw = 23,750

A 24KW Leaf takes about 12hrs to fully charge at 8 Amp so if we lined them up nicely we can to 2 shifts :)

So Manapouri could fully recharge 47,500 Nissan Leafs every day if it wasn't being used by the smelter.

Saying that most Leaf's only let you use 22KW of battery, and many people only recharge there Leaf every second day or so don't treat these numbers as anything more than an interesting unit of measure.

The problem is misunderstanding the units... a "24KW Leaf" is in fact a Leaf with a 24KWh battery... if you ran your Leaf at 24KW (32hp), the battery would last for 1 hour.

570MW is the instantaneous power usage of the smelter... in a 24-hour day it consumes 24x570 = 13680MWh = 13,680,000KWh

So the power it consumes could fully charge 570,000 Leafs. Given that you have to drive them sometime to discharge the batteries, I guess it could easily sustain a fleet of a million or more Leafs. Given intermittent usage, I'd say it could easily sustain all of the light vehicles in NZ, and a fair number of heavy ones too.

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frankv

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#2426439 24-Feb-2020 16:18

tripper1000:

If you really care about t he global environment, CO2, employment or the economy, then N.Z. should be building another 10 Manapori/Tiwai's and putting the grubby smelters out of business.

This kindof assumes that drowning valleys and making rivers unlivable for animals and birds is good for the environment.

tripper1000

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#2426441 24-Feb-2020 16:22

afe66:
djtOtago:

The math (I think) 64 x 24kw Nissan Leafs full charging every day for 1 year =~ 570 MW of power. So Smelter power would support 64 1st Gen Nissan Leafs fully re-charging everyday.

Is it that simple though ? Average electricity use per house per year in nz is more than 5000kWh (5MWh) so that would suggest Manapouri only supplies enough electricity for 100 houses using your approach...

Yeah, that math is shady. How many cars it might recharge is meaningless anyway. A more relatable way to analyse it is to look at how many KM's that power would propel a car.

An average Leaf gets 6km per Kw so that would propel EV's for around 3,420 million kms per year (?).

That's a big number. Maybe if we were concerned with the environment and energy security we should build another couple of Manapouri's and close Marsden Point instead!

tripper1000

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#2426448 24-Feb-2020 16:37

frankv:

tripper1000: If you really care about t he global environment, CO2, employment or the economy, then N.Z. should be building another 10 Manapori/Tiwai's and putting the grubby smelters out of business.

This kind of assumes that drowning valleys and making rivers unlivable for animals and birds is good for the environment.

Hmm again, a false argument - your response assumes digging up valleys for coal and making Antarctica and the oceans and globe unlivable for animals and birds is good for the environment - ?

Further more there is an assumption here that lakes are bad for birds and animals biodiversity which is also false. Water reserves like lakes can insulate animals from the effects of climate change by keeping the rivers etc flowing when there is climate change induced summer droughts. (edit: and conversely mitigating against the effects of flooding).

If we decide in hind sight that a particular dam is too damaging to the environment: 1) the damage is limited/localised to our back yard (ie you don't stuff up the entire globe like coal/oil does) and 2) we can drain a dam and restore the environment. I don't see anyone putting all that burnt coal and oil back in the ground to save the Great Barrier Reef or Antarctica. Do you? Besides, there are many valleys and we can conserve some/many for the birds & animals. . We can't really burn fossil fuels here and conserve other planets for the birds and animals can we?

loceff13

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#2426469 24-Feb-2020 16:57

tripper1000:

The CO2 produced by Tiwai is an completely false and baseless argument designed to capitalise on trendy hot topics/peoples ignorance. Closing Tiwai will lead to a net increase in the worlds CO2 production.

Aluminium requires an enormous amount of electricity to refine. Tiwai is one of the greenest aluminium smelters in the world with 90% - 100% of it electricity coming from renewable resources. Most other smelters rely on fossil fuel powered generation.

If you really care about t he global environment, CO2, employment or the economy, then N.Z. should be building another 10 Manapori/Tiwai's and putting the grubby smelters out of business.

Green produced isn't going to flood the market when it's cheaper via existing methods, the only reason why China isn't selling 95%+ of the market is US tarrifs on it

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