Power across the Tasman

Written By: - Date published: 8:22 am, November 30th, 2020 - 25 comments
Categories: australian politics, climate change, Environment, science, uncategorized - Tags: , , ,

Australia is likely to have less of an issue with raging bush fires this year. La Niña is likely to give a break to the droughts with a wetter East Coast. Doesn’t stop record heatwaves as is happening at present. Means that there are more grass fires than there were when grass wasn’t growing. And there is still a lot of bush to burn. Dozens of fires burning across NSW as cool change hits Sydney

This is pretty much the pattern that expected and long predicted with climate change. Everything involved with climate gets more extreme over time – especially in a continental climate like Australia. Even the short range predictions like the one from a week ago turn out to be somewhat less than what happens.

ABC: “Electricity supplies under pressure due to heatwave, energy market operator warns“

None of this is particularly interesting to me. It has been increasingly predictable to anyone who has been looking at the developing theory and data around greenhouse gases since my earth sciences undergraduate degree back in the later 1970s.

Regardless of how much ‘skeptics’ wish to stick their heads up their arse and try to deny they’re rapidly changing the world climate with their actions – it is going to keep happening. Much of the damage has already been done. Even if we stopped pushing greenhouse gases into the atmosphere right now, the effects will continue and keep getting worse for centuries. The trick for the current and coming generations is to limit making it worse.

What was interesting to me, is the current effects on the ecological and human made systems that we rely on. Australia, for instance, is demonstrating the problems of record heatwaves on grass and bush fires. It is also showing up weaknesses in their power grids. There is an accessible article at ABC “Electricity supplies under pressure due to heatwave, energy market operator warns” which explains the effects. Many of which we will see here.

The biggest impact on electricity demand, by far, is from air conditioners.

In Adelaide and Melbourne, demand could double in a heatwave due to air conditioning, Mr Skinner said.

“At about 7:00pm or 8:00pm on a typical Victorian weekday, the demand would be about 5,000 megawatts; on an absolute extreme stinker of a day, maybe 43 degrees or something, it would be around 9,500 megawatts. That’s huge.

“So more than half of the electricity will be going through an air conditioner, and then if the wind turns around the next day, all of those air conditioners will be off.”

ABC: “Electricity supplies under pressure due to heatwave, energy market operator warns“

While it is cooler here, our electricity market in NZ carries many of the same vulnerabilities. Extreme weather means exactly that. With more accumulated energy sloshing around our atmospheric, ocean, water, and even ice systems – it tends to accentuate effects that we have always had. It just makes them more frequent and/or larger.

Where a heatwave coming in from the tropics or a really nasty icy storm coming up from Antarctica used to be occasional. Now it happens a lot more often because there is more energy pushing them along. Rather than moving on, they are more likely to stall because of running into counteracting weather patterns.

That impacts on the power grids. Especially as we, like Australia, do a steady transition to the cheaper solar and wind technologies on top of our existing hydroelectric and geothermal systems. We need to dump the peak load thermal generation because it causes greenhouse emissions but that often has unexpected issues. For instance…

The job of instantly matching the amount of electricity Australians need with the amount of electricity generators make falls to the AEMO.

“Our role is to be able to forecast demand on the network with a degree of precision,” Mr Gatt said.

It coordinates the dispatching of generators by accepting bids to generate power, and, like any market, when demand is high and supply is tight, prices can go through the roof.

“Base loaders [like coal plants] will tend to bid at a lower price and the peak loaders [like gas plants] will bid at a higher price,” Mr Skinner said.

The first capital to feel the heat this week was Adelaide, which hit 40.6C on Friday — at 7:00pm, the wholesale electricity spot price in South Australia reached $329 per megawatt hour, more than eight times the average price.

“The peaking generators are obviously saying, ‘Well, I’m not getting out of bed until you give me enough money to make it worth my while’,” Mr Skinner said.

South Australia’s normally strong wind resources were only able to provide less than 10 per cent of Friday’s evening peak.

“There’s this unfortunate characteristic in South Australia where on really hot days, the evening peak in electricity demand often occurs with a lull in the wind,” Mr Skinner said.

With little low-cost power available to help keep prices down and interstate electricity imports at their maximum, expensive gas peaking plants set the price.

ABC: “Electricity supplies under pressure due to heatwave, energy market operator warns“

Plus of course there are other related issues.

On January 4 this year, Sydney was hit by 42-degree temperatures.

At the same time, bushfires in the Snowy Mountains took out transmission lines connecting New South Wales to Victoria, right when demand was highest.

Electricity spot prices skyrocketed, reaching $14,700 per megawatt hour in NSW late in the day — about 300 times the average wholesale price.

ABC: “Electricity supplies under pressure due to heatwave, energy market operator warns“

Here in NZ, we don’t have quite the same need to huddle under out air conditioners. However you can pretty well guarantee that when the weather gets really bad like a tropical store pounding Auckland or and icy blast trying to kill livestock in Southland – that is when our lines and distribution stations will suffer damage.

But then just the sheer absurdities of the engineers – unexpected gremlins.

Despite the AEMO’s best planning and forecasts, not every failure can be predicted.

On December 20 last year, when Melbourne reached 43.5C, a series of wind turbines unexpectedly switched themselves off.

“All of a sudden, over 1,000 megawatts suddenly just tripped out — we went from a system that appeared to be really fat, to having to put out an emergency reserve notice,” Mr Skinner said.

“It got really tight and nearly came to load shedding.”

It turned out the turbines were set to switch off at 40C to protect them from overheating.

“I don’t think even the owners anticipated it,” Mr Skinner said.

ABC: “Electricity supplies under pressure due to heatwave, energy market operator warns“

In New Zealand, we have a geographical issue as well. Much of our base load of various types isn’t usefully located. Much of the geothermal and hydrocarbon thermal capacity is in the North Island. Much of the hydro generation is in the South Island. The rationale pattern over the HVDC link is …

If all currently commissioned generation is available, both islands have enough generating capacity at peak times, without the connection between the two islands.[5] However, the HVDC link provides benefits for customers in both the South Island and North Island:

The link provides the South Island consumers with access to the North Island’s thermal generation resources that can support the South Island demand during times of low water storage levels and low inflows to South Island hydroelectric lakes.

The link provides North Island consumers with access to the South Island’s large hydro generation resources that can support the North Island demand at times of peak load.

The link plays an important role in the New Zealand electricity market, and allows North and South Island generators to compete with each other, therefore driving wholesale electricity prices down.[6]

Wikipedia: “HVDC Inter-Island – Rationale for the link“

Our generation capacity has and is diversifying especially with the geothermal and the wind capacities offsetting the falls in thermal generation. This reduces the probabilities of single cause effects. It is still overly dependent on localised rainfall and weather effects in both islands.

Year Hydro Geo-
thermal		 Biogas Wood Wind Solar Thermal Total Renewable
1975 16,497 1,350 41 306 – – 1,926 20,120 90%
1980 19,171 1,206 57 306 – – 1,972 22,713 91%
1985 19,511 1,165 105 336 – – 6,572 27,689 76%
1990 22,953 2,011 131 336 – – 6,028 31,459 81%
1995 27,259 2,039 172 336 1 – 5,442 35,250 85%
2000 24,191 2,756 103 447 119 – 10,454 38,069 73%
2005 23,094 2,981 190 277 608 – 14,289 41,438 66%
2010 24,479 5,535 218 345 1,621 4 11,245 43,445 74%
2015 24,285 7,410 244 349 2,340 36 8,231 42,895 81%
2018 26,027 7,510 261 289 2,047 98 6,895 43,126 84%
Wikipedia: “Electricity sector in New Zealand – Generation” ( GWh[27] )

Plus the lengths of our transmission links causes issues with the flexibility of our grid. A lot of the hydro capacity in particular is in the deep south, well away from the high density populations and industry of the north.

By Lcmortensen – Based from File:New Zealand locator map blank nobkgnd stdcolours.svg, edited in Inkscape to emulate Generation and Load map at [1], CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=6727038

Which is why the pumped hydro systems have started to be investigated about in the electricity sector. $4 billion Lake Onslow pumped hydro scheme could ‘tip electricity market on head’.

Although, I’d have to say that to me doing a lot of smaller pumped hydro projects in the North Island (away from the volcanic plateau) would seem to be to be a more rational idea. You might not get the nature built rock basins. But you would be able to site dams closer to the peak user areas with less of a transmission loss.

After all with the announced closure of Tiwai Point aluminium smelter, thereby releasing 13% of our power generation in the deep south, it seems like there may not be a reason

But I’m sure that the comments will tell me why my thinking is flawed 🙂

BTW: if you want to argue that human caused climate change isn’t happening or will be too minor to worry about – then don’t do it on my post. I’m getting very tired of illiterate dildos who are too lazy to read enough science to be worth arguing with. I will mock you and then ban you. There are other places to argue that – try one of our Open Mike posts. Other criticism of the ideas in this post are welcome.

25 comments on “Power across the Tasman ”

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  1. Andre 1
    30 November 2020 at 9:11 am

    In terms of transmission losses, New Zealand overall seems fairly low by global comparisons. The HVDC link from the big South Island lakes to Wellie loses about 6%. If it were extended to Orcland, it would lose about another 5%, leading to total losses around 11%.

    When it comes to pumped hydro, there's how much it stores and how fast it can ramp up and down to consider. The Onslow proposal would have massive storage – around 4 months of NZ total current electricity use. That makes it good insurance against dry years. But ramping generation or pumping up and down means accelerating and decelerating a 24km column of water – if you try to do that quickly you get some impressive pressure surges.

    Just a quick simplistic squiz at North Island topography suggests it shouldn't be hard to find pumped hydro sites close to existing water and grid infrastructure and nice short pipe runs so they can react quickly. For instance maybe in the Kinleith forest (although my geotech engineer brother sez a lot of the soils in that area are susceptible to piping).

    What have you got against sites near the volcanic plateau? For instance, there may some good spots above or below Lake Moawhango. Or the upper reaches of the Waipakihi (Tongariro) River might be suitable for a pumped hydro scheme (although it would be a long pipe to Lake Taupo and have the slow reaction time issue)

    • lprent 1.1
      30 November 2020 at 11:59 am

      What have you got against sites near the volcanic plateau?

      Risk statistics after being trained in earth sciences. There is no place on the volcanic plateau that doesn't have a very high probability of getting munted by volcanic activity.

      There is a shit load of NI capacity tied up in the volcanic plateau. Both hydro off the Waikato and geothermal concentrated there. After all most of the dams on the waikato are built on good solid Ignimbrite discharged in a pyroclastic flow straight down the Waikato at several hundred kilometres per hour and welded together by heat as it settled at 600C.

      Even if it was a 'minor' event (ie not a end of Taupo exploding), then you get butt load of ash going down most of the river valleys off the plateau.

      If you have any choice, you'd be better off siting further north or south of the plateau and reducing the risk levels in the event of a Rhylotic volcanic event.

      • RedLogix 1.1.1
        30 November 2020 at 12:14 pm

        There is no place on the volcanic plateau that doesn't have a very high probability of getting munted by volcanic activity.

        Yes. Being right in the middle of the 1988 Edgecumbe quake my first thought was "is this something local and survivable, or a regional volcanic event and not survivable?"

        • lprent 1.1.1.1
          30 November 2020 at 12:21 pm

          My father lives in a caldera called Rotorua. Knowing what I do, I'm always a touch nervous whenever I visit. He doesn't care – he is 81 and he likes the climate and the housing costs after my parents left Auckland.

  2. Adrian 2
    30 November 2020 at 9:41 am

    How about more solar in Northland ( closer to Auckland ) where the northern aspect presents more solar efficiency and then two dams with the water pumped by wind/solar up to the "battery" dam from the lower holding dam, you could probably even use seawater thereby eliminating the need for a bottom dam. When not being used for dam filling the solar/wind system could be fed into the grid.

    • Andre 2.1
      30 November 2020 at 10:07 am

      What you're describing for storage is commonly called pumped hydro. Using seawater for pumped hydro storage adds quite a lot of cost to the build. Just because of the more expensive materials and greater attention needed to preventing corrosion and dealing with stuff growing on it. That's not a deal-breaker by any means, it's just part of the reason why there's been much fewer projects done that way.

      Solar works well where a lot of the electricity demand comes from air conditioning. That's not the case in New Zealand, even in Dorkland. So our grid can certainly effectively use some solar, but beyond a certain lowish level of solar supply then the need for storage (and/or demand management) goes up quite quickly. Wind has the same issues.

      The term "dispatchable" is usually used for whether a generation source can be turned on and off and adjusted to supply what's wanted. Wind and solar are definitely not dispatchable, for their energy it's use it, lose it, or store it in something else. Some nominally dispatchable sources are so slow to ramp up and down they're better used as more or less steady base-load supply.

      Coal, combined-cycle gas (the more efficient gas generation), big nukes, hydro with long pipe runs, hydro sized close to the average supply of water (eg Manapouri, or run-of-river hydro), geothermal, are generally good for baseload. Then there's the fast-reacting sources for peak load. Such as straight gas turbines, hydro where the generator is basically on the dam so pipes are short, and increasingly, batteries.

  3. Redlogix 3
    30 November 2020 at 9:59 am

    NZ has to be one of the better placed geographies to go 100% SWB renewables, yet the entire OP is really a testament to the inherent limitations of this approach. The energy available is innately too diffuse and unreliable.

    We can work around these limitations in the near future, but we cannot ignore them indefinitely I think.

  4. Andre 4
    30 November 2020 at 10:27 am

    Demand management is another aspect of electricity supply that would benefit from more attention. A lot of infrastructure decisions are driven by the height of peak demand much more than average demand. Reduce the peak by spreading that demand onto lower-demand times, and the cost and difficulties of supply come down.

    Peak power demand reliably happens at the same times – the biggest peak in NZ is in the evening when dinner is cooking, TVs are switched on, the heaters are cranked up because everyone's home … There's generally also a smaller peak in the morning as people get ready for the day ahead.

    At those times, there are also a lot of users that could happily go a couple of hours switched off, but are still going full on because there's no incentive not to. Think hot water heaters, freezers…

    It used to be that all hot water heaters could and would be switched on and off by the electricity supplier using ripple control in the lines. That kind of thing is now a rarity. But there's no technical obstacles to reintroducing that and applying it to a wider range of users. It's also the idea behind plans such as Flick's retail scheme where you're charged the spot market price which varies by the half-hour, or Powershop's high or low price for different times of the day.

  5. Anne 5
    30 November 2020 at 10:30 am

    However you can pretty well guarantee that when the weather gets really bad like a tropical store pounding Auckland….

    Under La Nina conditions there should be a higher than average chance of severe tropical storms hitting the northern half of the North Island in particular.

    The region to pay the most attention to is the Coral Sea. With the advent of the La Nina plus Climate Change we could see a bumper crop of cyclones this summer season.

    https://www.windy.com/?-36.851,174.768,5

  6. Stuart Munro 6
    30 November 2020 at 11:50 am

    The one I'd go for would be tidal – not weather dependent, and Auckland is a prime site to moderate the relative levels of the Tasman & Pacific. Onslow looks a lot like the someone else's backyard you use instead of your own.

    • lprent 6.1
      30 November 2020 at 12:17 pm

      The obvious place for that is the Kaipara harbour. That has a serious daily in and out flow close to shore by both heads. The problem is that it is just too damn large for barrage – and so are most places in NZ (even ignoring other environmental considerations).

      The Kaipara is highly suitable for under water reversible rotors though. Pity that those aren't currently very viable.

      However, as far as I can tell most of the projects that are still being done of the kind we'd need (ie not dammed or barraged) are all still test projects – testing the hardware and commercial feasibility. Just figuring how to do maintenance in high flow areas without a barrage is a problem.

      current testing
      https://www.nsenergybusiness.com/features/tidal-energy-projects-2020/

      existing
      https://www.nsenergybusiness.com/features/worlds-biggest-tidal-power-plants/

      It kind of feels like fusion. A prospect whose utility recedes into my future as always being in the next decade.

      Whereas we have both solar (my parents had it viably working on their roof nearly a decade ago) and wind generation working for a while.

      • RedLogix 6.1.1
        30 November 2020 at 1:01 pm

        It kind of feels like fusion. A prospect whose utility recedes into my future as always being in the next decade.

        I really do see renewables as being a valuable bridging tech, we will need them because we're still around a decade away from a decent 4th gen nuclear rollout.

        Which is why I changed my mind on fission, despite the considerable effort and progress that has been made, fusion will still take an engineering breakthrough to deliver fusion tech at scale, on price. I firmly believe we will do it, but it remains a fantastically complex puzzle, and any implementation will be accordingly complex. And I have an aversion to over-complex systems when it comes to mission critical infrastructure like power grids.

        The energy roadmap as I see it for the rest of this century (barring any completely unforeseeable discovery) is:

        a) Another 15 – 30 years of renewable rollout that will only just counter the necessary decommissioning of coal plants. Natural gas will however continue to grow as the necessary backup

        b) Solid development is happening in the 4th gen nuclear fission space. We will almost certainly see operating reactors within five years and solid commercialisation by 2030. This will first happen outside of the developed world, places like Indonesia are already making early commitments.

        c) Sometime mid-to late century we could anticipate fusion to start coming online, but at least initially the technical demands will be so onerous I think it will be confined to nations capable of supporting it. By 2100 it will either be the dominant technology, or not at all.

        d) Sometime around 2040 the idea of a global HVDC grid to spread generation risks across continents will gain traction. But there are considerable political barriers and preconditions necessary before this can become realistic.

        None of this precludes parallel developments in efficiency, load management and less growth oriented economies, but ultimately zero carbon energy sources are the only way out of this mess. And by 2100 we will need somewhere between 2 – 10 times more than we currently consume, however you cut it.

      • Stuart Munro 6.1.2
        30 November 2020 at 2:05 pm

        It kind of feels like fusion.

        I get where you're coming from – not a lot of working examples – but the difference is that fusion requires developing technologies we really don't have – whereas tidal is an offshoot of the well-established hydro generation.

        I liked the isthmus because it wouldn't require the kind of damming that enclosing the Kaipara would – and thus less in the way of undesirable ecosystem effects. Some humans might have to move, but that's doable in principle.

        Mind, as sea surface temperatures climb, the marginal efficiency of OTECs should also rise – supposing that cooler deep water continues to be available.

        • lprent 6.1.2.1
          30 November 2020 at 6:21 pm

          I liked the isthmus because it wouldn't require the kind of damming that enclosing the Kaipara would

          You don't need to dam anything on the Kaipara. And I'm pretty sure that there isn't the expertise to do it anyway. The mouth is bloody wide and the water pressure is intense.

          The tidal bore close to the heads is very very powerful. It cuts a deep channel … You'd just need to put in propellers anchored on the harbour floor. That is the tech that really hasn't been fully tested yet.

          My grandparent used to have a batch in the old school house at Pouto. I used to dive off the beach and nearly got dragged along a few times. Not to mention being stuck fishing for an entire tide anchored in a boat because we literally couldn't pull up the anchor until the tide turned.

          Ummm – there is even a wiki page from the earlier attempt
          Kaipara_Tidal_Power_Station

          The Kaipara tidal power station is a proposed tidal power project to be located in the Kaipara Harbour. The project is being developed by Crest Energy, with an ultimate size of 200MW at a cost of $600 million.[1]

          Crest plans to place the turbines at least 30 metres deep along a ten kilometre stretch of the main channel. Historical charts show this stretch of the channel has changed little over 150 years. The output of the turbines will cycle twice daily with the predictable rise and fall of the tide. Each turbine will have a maximum output of 1.2 MW, and is expected to generate 0.75 MW averaged over time.[1]

          In 2013, it was announced that the project had been put on hold, and most of the shares in Crest Energy had been sold to Todd Energy.[2]

          • Brigid 6.1.2.1.1
            1 December 2020 at 11:59 am

            Yes I followed the Crest Energy project with much interest. Twas rather disappointed when it was put on hold. There was not much explanation as to why.

            • lprent 6.1.2.1.1.1
              1 December 2020 at 12:35 pm

              I am pretty sure that the problem was in the generators. It is 15 years later and I am not aware of any non-barrage system in place that isn't just a test system.

    • Graeme 6.2
      30 November 2020 at 1:14 pm

      Onslow isn’t that new, it’s been around since the 80’s and maybe earlier. When Clyde was being built it was the rationale for the provision if two extra penstocks at the south end of the dam. These were said to be for future pumped storage schemes to smooth peak loads.

      Lake Onslow has a dam on it already to increase head and storage for Pioneer’s generation schemes there.

      The big attraction if Onslow is it’s proximity to Roxburgh and Clyde and the ability to integrate with them. Also an ideal situation for that type of scheme. But I’ve got a local bias as it’s right in my backyard

      • Poission 6.2.1
        30 November 2020 at 1:55 pm

        Onslow isn’t that new

        Nothing new under the sun.

        The Provisional Committee was fortunate in securing at a very satisfactory figure the mining plant and water rights of the Roxburgh Amalgamated Company. This carries with it a valuable asset in Lake Onslow, which now becomes the property of the board and under its control. The conservation of water during the dry season will ensure a never-failing supply in the driest parts of the year.

        https://www.odt.co.nz/opinion/100-years-ago/teviot-power-scheme-planning

        The problem today however is that the cost of a 5b$ pumped storage system will be paid for by consumers,by increased costs for transmission,negating benefits to individual consumers that install small low cost solar ,that decrease the cost of transmission.

  7. roblogic 7
    30 November 2020 at 1:39 pm

    As well as building our generation capacity, we need to seriously look at ways to minimise demand, while also keeping emissions down. Electric vehicles won't save us, but maybe public transport & e-bikes/ e-scooters are a more sustainable and sociable way forward. Our addiction to driving around in 2 tons of steel and a mostly empty lounge suite, has to change.

    • Ad 8.1
      1 December 2020 at 8:26 am

      A rare and welcome success story.

      Cheers for that.

    • RedLogix 8.2
      1 December 2020 at 9:02 am

      On reading that article I do have a question arising from this para:

      “When the final two turbines are commissioned at Granville Harbour, Tasmania will have access to 10,741 GWh of renewable generating capacity – well above our average annual electricity demand of 10,500 GWh,” Barnett added.

      Well and good. This is indeed a positive milestone worthy of attention.

      But does it mean they have achieved zero carbon emissions? While their renewable nameplate generation capacity may now exceed their aggregate consumption for a whole year, this doesn't mean that renewables will necessarily provide all the power needed at every moment in that year.

      • William 8.2.1
        1 December 2020 at 1:12 pm

        Your last sentence sums up the situation. As I write this they are importing about 48% of their electricity from Victoria. Hope that link works OK, you may need to scroll to the region & click where you want info from.

        If you hover over the generation source in electricity map a popup will display the carbon intensity of that source, referenced from IPCC 2014, e.g. for wind it's 11gCO2eq/kWh, for hydro 24g. IPCC Annex 11 states

        "Hydropower: The indirect emissions of hydropower are largely associated with fossil fuel combustion in the construction of the plant."

        So a nice PR story, albeit about a move in the right direction, but at least it does only refer to electricity generation. The linked story from that page about 200% renewables makes the common error of confusing electricity with energy.

  9. Patricia Bremner 9
    1 December 2020 at 9:25 am

    In Towoomba NSW, during the last La Nina, they were heavily hit by cataclysmic rain and an inland tsunami.

    We were there six weeks prior, when heavy rain overcame the wipers on our vehicle and our vision, forcing us to turn and park in a side road.

    Within seconds water was gushing down the slight slope, like a fast running stream and we were pinned there for ten minutes. Within a day all the water had disappeared.

    We left a week later and the local dam was still dry as a bone, but all that changed as the La Nina kicked in and they had cloud bursts and torrential rain that filled all of the flood control dams to overflowing.

    The film of people in cars being washed away in the raging flood through Towoomba hit the tv screens. We knew those streets and some of the people. Tragic.

    The release of the flood gates added to the flooding in Brisbane.

    The La Nina season this season could cause the same grief. Australia has always had droughts and floods, the difference is the hubris of humans choosing to settle in dangerous places, removing trees scrub and wetlands with the resulting problems.

    The premise is always what we need with scant reflection of what nature needs to keep healthy cycles. So in our quest for electricity I hope planning covers possible damage and outcomes.

    It was 2011. NZ had 10 tornadoes, snow reaching Auckland, and 10 years on there is even more heat energy to come. Our plans better be considering that.

  10. left_forward 10
    1 December 2020 at 3:41 pm

    The Ngawha Geothermal extension near Kaikohe is also a very noteworthy extension to our power generation capacity in NZ. Northland will becomes a net generator of power when this comes on line next year.

    Ngawha Extension Project

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