Pumped Storage: what is the scale needed?

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#2530632 29-Jul-2020 10:45

Sidestep:

JessieB:

A far cheaper alternative to Lake Onslow is to keep the aluminium smelter, but have an electricity supply agreement where pot lines are shut down during dry years.

Erm - who would be responsible for (as in own/run) this massive loss-making excercise?

It would make the A$4.5 Billion Victoria's spent subsidising Alcoa's Portland aluminum smelter look like pocket change.

FYIW: of the two smelters in the article, Port Henry shut in 2014, and Portland is likely to shut in 2021- both were powered by coal power stations...

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#2530635 29-Jul-2020 10:48

SaltyNZ:

I've always been a dubious about that V2G function. I don't plug my car in overnight to discharge it: it needs to be charged in the morning when I am ready to go to work. And during the day it's sitting on the side of the road or in any case it's not plugged in (and if it was, I'd also want it to be charged when it was time to go home again).

I guess it's less important if you've got a battery 2.5x the size of the one in my Leaf, but even so I'd be annoyed if I got up to go on a long drive in the morning and found it had only 100km range remaining because it was balancing the grid overnight.

If NZ actually hits that 2035 ICCC goal of 50% electric vehicles the 'good old days' of unregulated EV charging from the grid will be long gone :)

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#2530636 29-Jul-2020 10:52

wellygary:

FYIW: of the two smelters in the article, Port Henry shut in 2014, and Portland is likely to shut in 2021- both were powered by coal power stations...

Yes it was economically futile to keep them operating.

Much like Tiwai point, there comes a time where it's best to give up just throwing money at them.

MikeAqua

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#2530662 29-Jul-2020 11:26

SaltyNZ:

clearly "it will pay for itself eventually" isn't that strong a driver to change behaviour, or everyone would already be driving EVs.

It's the age old problem of CAPEX vs OPEX on a limited budget. In theory you are better off making the investment, but you don't have that big wad of cash on hand. You can manage the ongoing smaller cost of buying petrol.

It seems like you need to spend >$10k to get a second hand EV that is probably OK. That's an expensive car for many people. Ironically, the people who can least afford one are the people who would most benefit from the saving of EV ownership.

You can borrow, but car finance is outrageously expensive. If have your own home you might be able to borrow at mortgage rates to buy an EV. If you rent a home, you don't have that option.

Then there is charging: If you don't have off street parking, you probably can't charge at home. If you don't have a garage you may not have an external charge point. If you rent - good luck changing that.

Mike

neb

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#2530766 29-Jul-2020 13:59

JessieB:
A far cheaper alternative to Lake Onslow is to keep the aluminium smelter, but have an electricity supply agreement where pot lines are shut down during dry years.

Shutting down (or more accurately restarting) a pot line is a major operation, you can't just flip a switch somewhere as needed. I could see that as being an impossible-to-agree-on thing, it'll never be quite bad enough to justify a shutdown, we'll hold on just one more week, or two, or three, in case it gets better, ...

wellygary

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#2530772 29-Jul-2020 14:11

neb:
JessieB:

A far cheaper alternative to Lake Onslow is to keep the aluminium smelter, but have an electricity supply agreement where pot lines are shut down during dry years.

Shutting down (or more accurately restarting) a pot line is a major operation, you can't just flip a switch somewhere as needed. I could see that as being an impossible-to-agree-on thing, it'll never be quite bad enough to justify a shutdown, we'll hold on just one more week, or two, or three, in case it gets better, ...

It took 6 months to restart Potline 4 ( the small one)

Stopping and starting a smelter on a semi-regular basis is a non-starter

mclean

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#2530795 29-Jul-2020 14:48

SaltyNZ:...I'm sure it would pay for itself eventually, but clearly "it will pay for itself eventually" isn't that strong a driver to change behaviour, or everyone would already be driving EVs.

Are you suggesting that the total cost of ownership of an EV is less than for an equivalent IC powered car? I don't think so, except for some unusual cases. Certainly not everyone.

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SaltyNZ

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#2530796 29-Jul-2020 14:50

mclean:

SaltyNZ:...I'm sure it would pay for itself eventually, but clearly "it will pay for itself eventually" isn't that strong a driver to change behaviour, or everyone would already be driving EVs.

Are you suggesting that the total cost of ownership of an EV is less than for an equivalent IC powered car? I don't think so, except for some unusual cases. Certainly not everyone.

Certainly has been for us.

iPad Pro 11" + iPhone 15 Pro Max + 2degrees 4tw!

These comments are my own and do not represent the opinions of 2degrees.

Scott3

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#2530818 29-Jul-2020 15:36

JessieB:

A far cheaper alternative to Lake Onslow is to keep the aluminium smelter, but have an electricity supply agreement where pot lines are shut down during dry years.

The report I linked to earlier analysed that option. (Based on the assumption that the smelter wouldn't be shutting up shop). In short, it isn't a cheap option (even if the smelter was willing to stick around).

INDICATIVE LARGE SCALE DEMAND
INTERRUPTION
It may be technically possible for a major load
(such as the New Zealand Aluminium Smelter
at Tiwai Point) to be fully interrupted for up to
eight months on a frequency of around 1 in
5 years. This is a substantially longer period
compared to the current demand response
arrangement between the New Zealand
Aluminium Smelter and Meridian.
This would not involve a significant capital
expenditure but would involve substantial
costs when called. The marginal emissions
abatement cost for the demand interruption
solution analysed was around $680/t CO2e.
It is very unlikely that such a service would
be commercially viable. For the New Zealand
Aluminium Smelter, or an aggregate of
smaller commercial loads, ceasing production
for a full eight months every five years
would be highly disruptive to contractual
arrangements for their respective markets,
regardless of the demand interruption
payment received.

https://www.iccc.mfe.govt.nz/assets/PDF_Library/daed426432/FINAL-ICCC-Electricity-report.pdf

Sidestep:

And that's because the Engineer's scope is limited to the technical aspects of designing and building these systems - fulfilling the functional objectives of a project - within the limitations of physics, practicality, safety and cost.

....

Holding coal fired Huntly in reserve – while acceptable from an engineering point of view, doesn't sit well with their goal of completely eliminating fossil fuels from the electricity system.

Frankly (as an engineer), politicians absolutely should be careful to set objectives & outcomes, but not pick methods or technologies.

I.e. Instead of "Light rail to the airport", It should be "Rapid transit to the airport"

Instead of 50% of the fleet be electric, it should be 50% of the fleet have no tailpipe emissions.

Regarding the last point, eliminating fossil fuels on the power grid sure makes a great soundbite, but to get from 99% to 100% involves a massive expenditure per tonne of co2 abatement. Essentially we need to build a heap of extra renewable generation for security of supply, then have renewable power plants sitting idle.

The one plus if we get to the last situation is we can ease back a bit where we are using geothermal resources unsustainable.

Scott3

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#2530834 29-Jul-2020 16:18

Sidestep:

Another CCC 2035 goal is having 50% of New Zealand’s vehicle fleet electric, and deploying up to 1,100 MW of battery storage, which is interesting in itself - More electric vehicles should increase electricity demand overall, but by charging overnight, they might eventually perform a similar function to pumped hydro at a lower cost.

With regards to zero emission vehicle's, this does seem to be the lowest cost way for NZ to reduce emissions.

If we got to 50% EV's, we would definitely need some system incentives charging in the 11pm- 6am window. With that, it could flatten our power demand to a point where existing hydro can easily cover the morning / evening spikes. Will work best if additional renewable energy is stuff that can run base load like run of river hydro, geothermal and to a lesser extent wind.

The battery thing is a bit odd. Note the massive range in the report (100 -1100 MW). We already have 6.75MW of grid scale batteries (plus whatever powerwalls are in private homes), so 100MW isn't a stretch if other lines companies do like vector and install battery stations instead of undertaking expensive lines upgrades to area's which are projected to exceed the capacity of their current lines for only a couple of hours a day.

That said, there is a report from the University of Canterbury which indicates that on NZ's relatively green power grid, that grid balancing battery packs, never pay back their production carbon emissions before they reach end of life.

Given our abundance of hydro, we are one of the least in need of this tech for general daily peak smoothing. Personally I feel it would be environmentally and economically better to do some minor hydro peaking upgrades, plus a little more load management. No need for my freezer to run it's power hungry defrost cycle at dinner time. That can wait for the middle of the night.

Other people have been talking about vehicle to grid. Personally I don't buy it for NZ. In NZ the best use for an EV with a cycle limited battery to reduce emission's, is to use it as an electric vehicle. The less cycles on the battery, the longer it will last. Having EV's with well managed batteries give 30+ years of service would be great for the environment (not Nissan leafs obviously).

SaltyNZ:

That would then require me to install a dedicated EVSE for 7kW+ AC charging, which is another expense that not everyone will feel like paying. I'm sure it would pay for itself eventually, but clearly "it will pay for itself eventually" isn't that strong a driver to change behaviour, or everyone would already be driving EVs.

In an ideal world, using charge timers would be the norm, and a smart gird would sort everything else out.

i.e. set your car to be charged to 80%, by 7am. Smarts will work out the best time to start charging based on the capacity of your EVSE and cars internal charger, along with projected grid capacity. if you have an unusual need (I.e. going out again in the evening), hit the override button, and it will charge immediately.

Regarding costs for EV's, they currently only work out economically in niche situations. i.e:

Swapping a petrol commuter car for a cheap-ish used leaf, when you do 100+km a week in it. (and don't need to take that car on long trips without stopping every hour)
Cross shopping a BMW 340i with a Tesla Model 3.
Cross shopping a range rover with a Tesla Model X.

In most other cases the number's don't work (even assuming the buyer takes a whole life analysis).

Compare an electric Kona ($78k for base trim), with a petrol one ($31,500). The $46,500 price difference buys a lot of extra fuel and maintenance.

In many brands (toyota) & sectors (Utes, station wagon's, full frame SUV's) there aren't even full EV offerings to consider (yet).

wellygary

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#2530839 29-Jul-2020 16:24

Scott3:

[Regarding the last point, eliminating fossil fuels on the power grid sure makes a great soundbite, but to get from 99% to 100% involves a massive expenditure per tonne of co2 abatement. Essentially we need to build a heap of extra renewable generation for security of supply, then have renewable power plants sitting idle.

Yeah, the overbuild needed to cover that last GWh for a cold still winter evening starts to get eye watering expensive... which is why I guess they are hoping that a pumped hydro solution that would also grid balancing on both a short and long term basis comes in a bit cheaper...

But on a $ basis a FF peaker is likely to be cheaper, ( even with offsetting)

Todd built a 100MW gas peaker this year for $100 million ,

https://www.stuff.co.nz/business/105362914/taranakis-new-100-million-natural-gasfired-plant-set-to-open-in-2020

Meanwhile Mercury spent $200 million on 100 MW of wind....

https://www.mercury.co.nz/news/20191112-mercury-commits-to-completing-new-zealand

( mind you that is 50% cheaper than West wind was a decade ago, when meridian paid $440 million for $143MW at West wind)

(and yes I know that the wind will only run at 40% capacity over a year so the GWH outputs aren't strictly compatible, but its a useful "back of the envelope comparison- and the comparative cost per GWH for the peaker is probably lower still)

frankv

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#2530867 29-Jul-2020 16:51

Jase2985:
you could plug it in at 6pm when you get home, use power from the car till night rates kick in then change to charging the battery in the car. use the cheap power from the car battery, instead of expensive peak power pricing.

Why would there be cheap night rates? If there was money to be saved, people would move to it until there was no net savings.

Not to mention that when you get home your car battery is already low. Unless you carted around a bigger than necessary battery. Wouldn't it be more sensible to have a cheap, heavy,large battery at home?

Scott3

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#2530898 29-Jul-2020 17:44

wellygary:

Yeah, the overbuild needed to cover that last GWh for a cold still winter evening starts to get eye watering expensive... which is why I guess they are hoping that a pumped hydro solution that would also grid balancing on both a short and long term basis comes in a bit cheaper...

While the pumped storage is great for helping out with the dry year event's, and to chip in with winter evening's, It doesn't remove the need to overbuild completly.

The event we then become concerned about is consecutive dry years. We still probably need to overbuild by (at a guess) 3 - 5%. That way we can handle a small dip in annual generation (say a lowish rainfall, or wind year, or a major geothermal plant fault requiring 6 months shutdown for repair.

Even then we will need to scramble for solution's, or call for power savings if we have consecutive high return period dry year events. Would be pretty worrying if we just got through a winter by drawing down hydro storage, and snow pack analysis shows that there isn't much water to come down.

Perhaps the government could have just happened to have taken possession of a couple of mothballed fossil fuel plants (conveniently including a giant coal pile), which could be quickly re-commissioner to save the day.

frankv:
Why would there be cheap night rates? If there was money to be saved, people would move to it until there was no net savings.

Not to mention that when you get home your car battery is already low. Unless you carted around a bigger than necessary battery. Wouldn't it be more sensible to have a cheap, heavy,large battery at home?

On the topic of cheap night rates, NZ doesn't have the extreme daily swings of other countries. Wholesale rates didn't really get below $100 last night (upper north), had a short peak just past $250 at breakfast time, and have sat around $150 - $180 most of the day. Prob will see $250 - $300 at dinner time. This time of year has the greatest price swings due to domestic heating. Business case for home batteries for the purpose of balance this is weak.

With greater uptake of EV's (amusing night charging by default), and a move from gas to electric domestic hot water (existing TOU controls), the business case would be weaker still.

Most pure EV's have a bigger battery than is used daily for unusual trips & safety margin. It is only really PHEV's that can use their full battery each day. That said, it's not like that power is usable. Most EV owners are keen to keep a bit of power in the battery incase they want to use the car at short notice.

Long term I expect to see more load shedding rather than than batteries to do daily load leveling. A tesla powerwall is expensive and has a round trip efficiency of 90%. Delaying a freezer defrost cycle or an EV charge from starting has no efficiency losses, and only takes a little circuit board to make it work, rather than a heavy, expensive battery. Of course smart gird stuff has been on the agenda for decades and hasn't happened yet (except for hot water).

Tracer

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#2531050 29-Jul-2020 21:03

neb:
JessieB:

A far cheaper alternative to Lake Onslow is to keep the aluminium smelter, but have an electricity supply agreement where pot lines are shut down during dry years.

Shutting down (or more accurately restarting) a pot line is a major operation, you can't just flip a switch somewhere as needed. I could see that as being an impossible-to-agree-on thing, it'll never be quite bad enough to justify a shutdown, we'll hold on just one more week, or two, or three, in case it gets better, ...

It's been done for dry years at least a couple of times before. Demand response is an active area in the smelting world: https://www.greentechmedia.com/articles/read/german-firm-turns-aluminum-smelter-into-huge-battery. I don't think it's got any chance here though, because our electricity is simply too expensive.

Sidestep

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#2531158 30-Jul-2020 05:39

Tracer:

It's been done for dry years at least a couple of times before. Demand response is an active area in the smelting world: https://www.greentechmedia.com/articles/read/german-firm-turns-aluminum-smelter-into-huge-battery. I don't think it's got any chance here though, because our electricity is simply too expensive.

Well, you've touched on a sore spot there! Just another huge missed opportunity for NZ..

The innovation at Trimet’s Essen smelter didn't involve turning potlines off, but allowed supply to individual pots to be dialed up or down by 25 percent in either direction, for up to several hours - or even off, for short periods - allowing production to continue, and obviously not allowing the molten aluminium to set.

Of course to do this the smelter must be integrated with the country's grid.
The changes allowed 'storage' (or variation of demand) of approximately 2000 megawatt hours, the equivalent of a medium pumped – hydro system.

The key was cladding the electrolysis cells in newly developed EnPot shell heat exchangers – which dissipate heat when the energy input is increased, and insulate the pot when energy input is reduced.

Trimet and Bergische Universität Wuppertal developed a measurement and process control system to optimize smelting performance, and deal with magnetic field changes under flexible power input conditions using modified conductor rail systems..

If the political will had existed to connect Tiwai/Manapouri to the National grid a decade ago this could have turned out so differently...

The Enpot System was developed by NZ's own Energia Potior and could have been harnessed to turn the Tiwai smelter, in effect, into a giant capacitor, evening out fluctuations from renewables, with the smelter/Meridian both selling to, and purchasing power from, the rest of NZ.

Rio's other hydro-smelter operations in Canada have been mentioned, and provide a clue as to what saving Tiwai could have looked like, and also why it's just not viable to keep running it.

Their hydroelectric kit is providing smelter power at 'below cost' in this low aluminium price environment - they're not pricing in replacement, refurbishment or 'opportunity cost' of the power they're using. Since they own most of the hydro plants this doesn't matter (short-term).

The key is, their Hydro-powered smelters are grid connected, and can be used to supplement and even out supply/demand in their respective Provinces, making the whole thing a plus-plus situation for Canada.

The Rio owned Kemano hydroelectric generator (a similar design to Manapouri) produces 896 MW of power, and supplies their Kitimat smelter with one of the lowest power costs in the world (around US$ 8/MWh) but the excess - generally about 20% - is sold to the Provincial power utility, and sold back to them (at a profit) when they need it..

It's other Canadian smelters (of which four are wholly owned) all in Quebec, run on power produced at less than US$10/MWh – Rio's (six in total) Hydroelectric Plants there, with a theoretical capacity of 3,000 MW (though actual production is less) also power Rio's local Alumina refinery.

And of course, a full grid connection allows Rio to both sell to, and buy from, Quebec's Provincial utility.

Now NZ's Manapouri grid connection (ironically, with lines made from aluminium) will still have to be built, but hurriedly and with far less immediate benefit than a proper transitional plan would have allowed.

Saving the smelter now? Not likely.. Winston's still yelling at the Ref but the final whistle's gone.

The game was pretty much over back in early 2019 at the Davos summit, the PM throwing a hail Mary when she asked Rio CEO Jean-Sébastien Jacques for a path to convert the plant to their new carbon-free production technology, and got no change in their efforts to sell the place.

As a RIO shareholder I approve of their decision to walk away.
As a New Zealander, I'm disappointed we didn't take advantage of the opportunities that existed, but glad there's finally some closure, and optimistic we'll take advantage of the new opportunities this presents.

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