Battery of the Nation could need four new interconnectors | RenewEconomy

Battery of the Nation could need four new interconnectors

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Tasmania’s bid to become battery of nation could require as many as four new interconnectors to be installed between the island state and mainland Australia.

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Tasmania’s bid to become the battery of the nation, providing the NEM with as much as 2.5GW of pumped hydro energy storage capacity, could require as many as four new interconnectors to be installed between the island state and mainland Australia, a report has revealed.

HydroTasmania yesterday announced that feasibility studies backed by ARENA had uncovered the potential for Tasmania to provide just under 5GW of storage capacity from just 14 of its best pumped hydro sites.

The solution was also heralded as being “cost competitive against all other realistic options” for the future NEM, with ARENA estimating total capital cost of $1.1 – $2.34 million per MW to develop around 2500MW of Tasmania’s most optimal pumped hydro sites – most of them coming in under $1.5 million per MW to build.

But how to get all that stored renewable energy – boosted by a ramping up of Tasmania’s wind power generation capacity – to the mainland?

HydroTas and ARENA have both acknowledged that “fully unlocking” Tasmania’s pumped hydro potential would need additional interconnection with the rest of Australia, beyond the existing Basslink cable – which itself returned to service this week after a 10-week outage.

Plans for a second interconnector are already being considered, via an ARENA and Tasmania government-backed business case study announced late last year – and at the time billed “a critical milestone for Battery of the Nation.”

But a closer look at HydroTasmania’s indepth report, Battery of the Nation: Analysis of the future National Electricity Market, suggests that up to four new interconnection cables could be necessary between Tassie and the mainland, depending on the amount of new pumped hydro and wind power capacity being added to the mix.

As the chart above illustrates, the largest scenario explored – which meets just 20 per cent of total projected demand for dispatchable capacity on the NEM through to 2040 – no less than five interconnectors would be needed.

For the 2.5GW of pumped hydro scenario that was flagged yesterday as the ideal, a total of four interconnectors would have to be installed by the early 2030s.

On cost, however, the report says that the two major contributors in the Battery of Nation project would be the variable gas costs (fuel) and the wind energy.

“This analysis shows the transmission and interconnection costs are only a minor contributor to the overall investment required.” the report says.

As we reported here, a 2016 report into the feasibility of adding a second undersea link suggested it would not be worth the $1 billion investment unless at least 1,000MW of new renewable energy capacity was built in Tasmania.

And not everyone is convinced that a second cable is the way to go, when the installation of grid-scale battery storage alongside renewable energy generators – and harnessing the collective resource of behind the meter battery storage in homes and businesses – could offer a cheaper and easier fix to problems of balancing variable wind and solar recources.

In one scenario, drawn up by the Australian Energy Market Operator, AEMO found that the benefits of installing a second Bass Strait interconnector might outweigh costs over a 20 year period by just $20 million, and that those benefits might be eroded if battery storage costs continued to fall.

Earlier this year, Infrastructure Australia put the cost of a second basslink cable at about $1 billion to build.

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  1. Joe 2 years ago

    The COALition could set up a NAIF for Tasmania and use some of that loose $5 Billions currently sitting around with no where to go to. But then the money for Tassie isn’t for a Coal connected project so Tassie misses out again I’m afraid.

  2. Peter Todd 2 years ago

    There are lots of benefits for system reliability and reduced expense of new or upgraded interconnectors with distributed storage. Tasi big battery is the opposite of distributed storage. Some pumped Hydro and more wind for Tasi is logical but lets do it step by step with the most cost effective first. Same with Snowy Hydro as they can do more pumped hydro as well without spending too many millions on gold plated schemes (Snowy 2).

    • Jonathan Prendergast 2 years ago


  3. john 2 years ago

    Putting in enough connection to the main grid may cost in the short term.
    Looking at the long time benefit will prove if this is the way to go.
    What i mean if they can buy at low cost of energy or when the grid is oversupplied they pump up the PHES to store energy.
    Obviously when demand is high or above the cost to store that energy they deliver the energy .

  4. Ken Dyer 2 years ago

    The cost would be less than a new and rather small coal fired power station, wouldn’t it?

  5. Ken Dyer 2 years ago

    Why four interconnectors? How about one big one connected to four points in Tassie. Who drew that stupid diagram anyway?

    • Chris Fraser 2 years ago

      Redundancy. Better to spread the risk of having one failure. It takes ten weeks to fix just one. That repair time needs to improve quickly.

      • RobertO 2 years ago

        Hi Chris Fraser, It can take many months just to get a cable ship here in Australian waters. Finding the break can add more time and then you have to lift it from the sea floor, repair it and then put it back on the sea floor and then start the procedures to restart the cable.

        • Ken Dyer 2 years ago

          For 100% redundancy you only need two. The second Bass Strait interconnector is with Infrastructure Australia now. Cost is estimated to be one billion dollars. Still cheaper than a coal fired power station but don’t tell the LNP COALition that.

          Perhaps now that Tassie has a LNP government, it might get a leg up, but I am not holding my breath. Why? Because one new interconnector supplying clean, cheap renewable energy will threaten the old, dirty, polluting and expensive water boiling mob, you know, the ones who use COAL.

    • RobertO 2 years ago

      Hi Ken Dyer, there is more that one option for connecting Tassie to the main land. One very large cable with earth return, two large cable one in one out with earth return, three cable two in and one out with earth return (and you could even put a spare cable with any of the above). The life expectancy of cable is about 60 years (according to ABB info) and warranty is to use an insurance company (sellers pay for the first period and owners pick up the rest).

      • Ian 2 years ago

        The lovely diagram quoted by Sophie shows the interconnectors being developed 5 years apart. The first new one being 600MW. Would there not be a benefit to building a larger capacity ab initio, rather than redoing this development each time?

        How much of the cost of setting up an interconnector is related to the connecting infrastructure at each end and transporting and laying the cable in the middle? Cost savings would be achieved most likely by importing skilled personnel and cable laying ships only once for a big cable system rather than twice or three times for smaller cables?

        Wind farms can be thrown up very quickly, and there is a huge appetite for renewables investment in Australia. For instance labor’s NW corner of Tasmania renewable energy zone could support a large wind energy development. Upgrading the existing single use hydro generators with a larger generator capacity and perhaps some pumped hydro to better manage the dispatchability of the existing hydro dams could also be achieved reasonably quickly.

    • Nick Kemp 2 years ago

      An what happens when it breaks down as the current one has at the moment and for around 6 months last year? No lights on the mainland?

      • Greg Hudson 2 years ago

        NO. The lights stay on thanks to SA exporting bucket loads via the interconnectors to Vic. Fingers crossed they don’t build one to NSW 😉

  6. Jon 2 years ago

    It seems more than a little odd to me to be moving to distributed generation model and put the battery right down one end of the grid.
    We read recently about the factor being applied to generation that is not near high demand centres, sending electricity on a 2 way trip across bass straight would have to have some losses tat would need to be covered in the arbitrage costs.
    Getting it across Bass Straight is only part of the problem; it would then need upgrades to the mainland distribution network.
    There’s a lot of mainland potential (including Snowy 2.0) that are more logically located I believe, makes Kidston Pumped Hydro look suburban in comparison.

  7. RobertO 2 years ago

    Hi All Here the European Commission 2015 report on HVDC Sea cables

  8. Mark Buskens 2 years ago

    In my opinion this is a project that shouldn’t be considered until well down the track.

    The Major Cost components are.
    * Interconnector’s to Victoria. ($B’s)
    * Cost to Develop Pump Hydro (Not sure, but guess is $B’s)
    * Wind ($B’s).
    * Upgrades to Terminal Stations/Transmission Lines in Tasmania/Victoria & anywhere else you want to send the Power ($B’s).

    Then you have to consider what benefit does this provide to NSW/QLD/SA for peak Demand? None they will be constrained, so realistically you would to include upgrading those interconnector’s ($B’s).

    I think this is going to fair poorly against Renewables/Localised Pumped Hydro/Battery Storage in each region QLD/NSW/SA/VIC, etc. Especially considering in some of those regions you are working off such a low base still when it comes to Renewables/Intermittent Generation.

    Rather than such a focus on pumping so much of this power to the mainland, what about getting the heavy energy user’s to move to Tasmania,

    In any event this is all ‘pie in the sky’, when you consider the opposition this might have from the Greenies in Tasmania. Will they accept overdevelopment/exploitation of Tasmania for the benefit of the mainland?

    • Nick Kemp 2 years ago

      “Rather than such a focus on pumping so much of this power to the mainland, what about getting the heavy energy user’s to move to Tasmania,”

      Indeed – It wasn’t that long ago that businesses here seemed to be closing due to high energy costs. We should be refining and smelting our ore etc at a rate of knots on the back of wind and hydro power. When we sell our power to the mainland we basically import mainland prices with the state govt telling us that the dividend they receive from hydro is a great thing rather than a tax

      • Brian Tehan 2 years ago

        Aluminium is the obvious industry. Industries that require hydrogen, such as ammonia?

  9. LN 2 years ago

    Only problem is that one of the main reasons for building Snowy 2.0 is the closure of Liddell – capacity is required in NSW

  10. RobertO 2 years ago

    Hi All, Remember that this is a plan (it what we need for Australia a thing called a plan). I believe that not all of this will be built even in the next 21 years, some might be such as a second interconnector with some 1500 MW of wind and the odd standard hydro may change to a peaking hydro and maybe 1 or 2 PH systems (the best ones listed) such that Tassie becomes a almost full time exporter. In 20 years time we may consider some additional changes to make the rest of the NEM more secure such as a third interconnector.

  11. Nick Hunn 2 years ago

    You might want to reread the difference between energy and power and have another crack at this article.

  12. BushAxe 2 years ago

    It doesn’t seem realistic to pump power across Bass Strait twice? Focus should be turning Tassie into a REZ with 5GW of wind firmed with PHES and another 600MW interconnector to supply the NEM as a 10 year goal.

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