North Island National Grid at near Capacity

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#2757940 10-Aug-2021 13:00

Dingbatt:

The new F150 Lightning can power a house (according to the Ford blurb). So when are we getting them here?

Soon I hope. If you have the right vehicle you'll be able to drive right underneath those monsters and get to the front of the lane at every set of lights on your twice daily commute.

Zeon

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#2757943 10-Aug-2021 13:04

Hasn't the wholesale market price of power been high up for quite a while now? Perhaps the construction costs are much higher than when they originally wanted to obtain the consent... that is an expensive process to let it lapse and do nothing with it.....

Speedtest 2019-10-14

Scott3

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#2757950 10-Aug-2021 13:15

For people talking about why many consented power stations haven't been built, consider:

Power demand has basically flat lined since about 2006. Little need to build more capacity, and what does get built is cherry picked stuff that offers great value, and will need to essentially compete and undercut other existing assets in the market.
Closer of the smelter has been looming for decades. In the event of it closing the power that will be freed up will depress wholesale electricity prices for 5+ years, meaning those that have recently built generation will loose money.
More generation will depress future wholesale prices, which is not in the best interest of the current large generators, who are the people with greatest access to capital & skills to build more generation.

I view our current market system as essentially broken. In it's current form it is incompatible with a 100% renewable system, which has to be the goal in a decade or two's time.

NZ used to be one of the most efficient electricity producers in the world, and New Zealanders enjoyed very low pow prices. Despite this we tried to make it more efficient by privatization. Didn't work out...

Going forward we need one of the following:

Re-nationalize the sector
Re-work the market to encourage the behavior we want.
Ditch the market, and have a regulator dictate what is a reasonable amount of income / profit for each power station based on its age, operating costs etc.

Groucho:

Anyone have insights as to why NZ hasn't got tidal power in the mix?!? We are surrounded by coastline which makes it ideal to set up a large scale tidal farm somewhere outside of shipping channels. Alternatively mini tidal farms dotted around the country which can be fed directly into regions lessening the reliance and load of the national grid particularly inter-island.

For decades we've had generation issues of low hydro lakes or no wind or no sun for solar (being off peak when generated anyway). Last I checked there's never been wildly varying tides on the sea floor.

If we're serious about being 100% renewable energy, tidal has to be the way forward? Demand is going to keep increasing, coal plants will be gone and climate change will presumably give the hydro lakes increasing cause for concern. Meanwhile EVs would like more share of the energy pie and domestic fires are being phased out in favour of clean heat pumps (doubling as air conditioning in our warmer summers). Fires can be a double energy blow as they provide heat and for those with wetbacks FREE hot water.

In a word, Cost.

If you have ever done any marine stuff, especially with submerged moving parts, the environment is really harsh... Construction and maintenance costs are high... Locations are cherry picked to be highly tidal which makes it even harder.

And consider this in the knowledge that NZ has some of the best renewable energy resources in the world, which is far from fully utilised. As an example a wind turbine installed in the Taraura wind farm will make twice as much power as the same windfarm installed on an average european site... Stuff like geothermal, wind seem to be the most economical at the moment in NZ.

I have a bit of interest on the topic though. There are two main ways to do tidal power:

Tidal Barrage

Most well known is the 1966 Rance Tidal Power Station in France

Basically you build a dam across a harbour / lagoon etc. In the above example this is 750m long, and the lagoon is 22.5km^2 Differences in water level between different sides of the dam are exploited in order to generate power. As there is not always water level differences, it can't allways generate. Capacity factor of this one is 28%. On the plus side it is competently predictable, on the negitive side it is way less than the 46% we get from a wind turbine at Taraura.

Note that that location has a 8m tidal range, NZ has 3.5m max, so that location would be at least twice as good as what we could do here.

Environmental impacts of this approach are typically not negligible.

Tidal stream.

Think a wind turbine, but underwater.

I think there are only small scale pilot programs of these. Most well known is Seagen. Which was commisioned in 2008 and decommissioned in 2019.

https://en.wikipedia.org/wiki/SeaGen

There was a proposal to install this kind of setup in the kaipara, and a different one for the cook straight, but neither got off the ground.

Regarding 100% renewable's, it sounds good, but you hit serious diminishing value as you approach 100%. Overbuilding renewable's enough to handle a 1:10 return period dry year even't, and keeping a bit of coal / gas / diesel on standby to bail us out if we get a 1:100 dry year event will get us to something like 98 or 99% renewable at much lower cost than going fully renewable.

Scott3

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#2757952 10-Aug-2021 13:21

Zeon:

Hasn't the wholesale market price of power been high up for quite a while now? Perhaps the construction costs are much higher than when they originally wanted to obtain the consent... that is an expensive process to let it lapse and do nothing with it.....

They have been up for a couple years or so, and more (small) projects are getting the go ahead, but the panned smelter withdrawal will be causing reluctance to invest.

- Note that the build time of a windfarm is quite long, and the current situation (dry year stacked on top of natural gas production issues) is considered a rare event, rather than the new normal.

Also there are a lot of stars that need to align to get a windfarm a go ahead. Things like forex rates, and reasonable lead times from your perfected vendors etc.

MrAmerica

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#2757953 10-Aug-2021 13:21

Re Tidal streams, there is a new one called Orkney O2, it produces 2MW

https://www.youtube.com/watch?v=4d9zs0W9u2A

Gurezaemon

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#2757962 10-Aug-2021 13:31

Groucho:

Anyone have insights as to why NZ hasn't got tidal power in the mix?!? We are surrounded by coastline which makes it ideal to set up a large scale tidal farm somewhere outside of shipping channels. Alternatively mini tidal farms dotted around the country which can be fed directly into regions lessening the reliance and load of the national grid particularly inter-island.

For decades we've had generation issues of low hydro lakes or no wind or no sun for solar (being off peak when generated anyway). Last I checked there's never been wildly varying tides on the sea floor.

If we're serious about being 100% renewable energy, tidal has to be the way forward? Demand is going to keep increasing, coal plants will be gone and climate change will presumably give the hydro lakes increasing cause for concern. Meanwhile EVs would like more share of the energy pie and domestic fires are being phased out in favour of clean heat pumps (doubling as air conditioning in our warmer summers). Fires can be a double energy blow as they provide heat and for those with wetbacks FREE hot water.

I think this was looked into at the mouth of the Kaipara Harbour, but the usual environmental concerns were raised.

Given the strong tidal flow through the Cook Strait, it strikes me that it would be perfect for some deeply positioned turbines. The technology has matured quite a lot recently, with a successful pilot project off the coast of Scotland.

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Dingbatt

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#2757966 10-Aug-2021 13:46

At least the orbit of the moon around us and us around the sun is virtually perpetual (at least in human terms) so the tides can provide cyclic power generation day in, day out. If something happens to the Sun and Moon I think we will have bigger problems.

“We’ve arranged a society based on science and technology, in which nobody understands anything about science technology. Carl Sagan 1996

Gurezaemon

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#2757976 10-Aug-2021 14:06

Some form of battery such as that in South Australia, but without the various issues and cost of lithium would be nice. I saw this recently, and it looks suspiciously feasible. Am I missing something?

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tdgeek

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#2757980 10-Aug-2021 14:18

Woods pointed the finger at Genesis Energy, owner of the Huntly Power Station, who did not turn on the third coal/gas boiler as it did not expect it would be needed, despite Transpower forecasting huge demand as it was one of the coldest nights of the year.

She also said Transpower, who operate the national grid, had taken about twice as much power out of the system as was actually needed.

Genesis should have but didn't think it needed to be on, Transpower cut off too may people.

Scott3

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#2757992 10-Aug-2021 14:46

"A Genesis Energy spokesperson said it hadn’t expected to need one of its gas/coal boilers but a “unique set of circumstances” had reduced North Island generation capacity its Tokaanu hydro planet near Tauopo and wind farm in Waipipi.

The boiler would have then taken several hours to get operational.

Gale force winds earlier in the day at Tokaanu pushed weed into the intake, and then a sudden decline in wind in the evening affected central North Island wind generation.

“There was no third rankine [boiler] operating as there was sufficient generation capacity available to the market prior to the loss of generation at Tokaanu and sudden decline in wind generation that coincided with peak demand."

https://www.stuff.co.nz/national/politics/300378816/live-megan-woods-blames-commerical-decisions-for-power-blackouts-genesis-energy-says-it-didnt-generate-extra-power

This is an extremely bad look for genesis and the industry. My previous assumption that one of the huntly coal units was unavailable was wrong it seems.

The decision was made not to start it, and a fault at a single hydro plant, and a period of lighter than expected winds meant that the industry failed at in its main role to keep the lights on...

Im sure there will be an epic aftermath to this, and note that the third coal unit did not appear to be running this morning either, despite pretty much no reserves begin available.

I don't really blame genesis in this. Clearly the market as it currently stands isn't providing them sufficient incentive for them to carry the running cost's of Huntley when so the market has decent reserves at times like last night / this morning.

frankv

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#2757995 10-Aug-2021 14:50

Groucho:

Anyone have insights as to why NZ hasn't got tidal power in the mix?!? We are surrounded by coastline which makes it ideal to set up a large scale tidal farm somewhere outside of shipping channels. Alternatively mini tidal farms dotted around the country which can be fed directly into regions lessening the reliance and load of the national grid particularly inter-island.

Tidal power isn't quite as simple as dumping something in the sea and plugging it in. Tides around NZ are only about 2m, so you won't get much power from the normal rise and fall. You do get a lot of power if you harness the currents caused by tides, so you're looking for places where there is a large area of water with a very narrow opening to the sea. As the tide rises, water rushes through the opening to fill the area behind. By the time it's full, the tide is falling so the water has to rush out again. What the above describes is pretty much a harbour, and harbour mouths have lots of shipping. Except most West Coast harbour mouths, because they are subject to large sandbars that move around. So the only harbour that's been touted for tidal power has been the Kaipara. The Marlborough Sounds also offer a couple of possibilities, Tory Channel and French Pass, but Tory Channel is on the ferry route.

The tides on each side of NZ are opposite to each other, so Cook Strait itself (and maybe Foveaux Strait?) is a possibility, but with much lower flow rates over a larger area. Another idea I have heard of was to run a large pipe (canal?) across Auckland from the Waitemata to the Manukau, but I think there's ecology issues with transporting flora & fauna from one harbour to the other. Also, I doubt that you could have a large enough pipe for this to be economic.

Wikipedia has a good article on NZ tidal power.

I suspect that wave power might be more viable than tidal, and off the West Coast probably almost as reliable.

tdgeek

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#2758006 10-Aug-2021 15:08

Scott3:

I don't really blame genesis in this. Clearly the market as it currently stands isn't providing them sufficient incentive for them to carry the running cost's of Huntley when so the market has decent reserves at times like last night / this morning.

On the one hand they need to satisfy shareholders, so not starting a burner helps this to a degree as buyers may not pay the extra, but they are sailing pretty close to the wind, when a possibility of another issue catches them with their pants down. This probably happens a lot, and no other event occurring at the same time is probably the norm.. Having said that its no doubt hand to mouth stuff in real time, but you need a level of redundancy, and that wasnt there

empacher48

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#2758035 10-Aug-2021 15:34

Scott3:
Im sure there will be an epic aftermath to this, and note that the third coal unit did not appear to be running this morning either, despite pretty much no reserves begin available.

As long as the government wants to buy my meridian and genesis shares back somewhere more than the market rate, then that’s fine.

But the way our government is going, there will be a lot of noise, more wind than what can power our turbines and in a fortnight’s time this will be forgotten and nothing will change.

duckDecoy

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#2758039 10-Aug-2021 15:41

Groucho:

If we're serious about being 100% renewable energy, tidal has to be the way forward?

I doubt we will ever be 100% fully renewable. The government and transpower have been running models around this scenario and the amount of redundancy that has to be built into the system to handle that one unlucky day when the sun isn't shining that much and the wind wasn't blowing quite right is mind blowing.

More hydro would be really helpful, but getting resource consent is just too hard.

wellygary

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#2758041 10-Aug-2021 15:51

Scott3:

This is an extremely bad look for genesis and the industry. My previous assumption that one of the huntly coal units was unavailable was wrong it seems.

The decision was made not to start it, and a fault at a single hydro plant, and a period of lighter than expected winds meant that the industry failed at in its main role to keep the lights on...

Someone has thrown Genesis under a bus here and I suspect it was T/power....

BUT its still not clear why the HVDC link was only delivering 635MW north last night... its was cranking up to 775 MW at noon today....

and also the numbers don't really stack up ,

Tokaanu is 240MW, and Waipipi is 135MW, meaning this outage is being blamed on a max of 370MW was not being utilised.... A Rankine unit is only 250MW,

My guess is that there was a whole lot more wind off line as well, but I would also like to know what happened to the cogen at Kawarau now that N Skog have closed their mill....

Hopefully we actually get a decent report from the EA on this event, but I'm not holding my breath for one....

Genesis have been taking $hit for months over burning coal to keep the lights on, and when they try to dial it back they get hammered....

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