Utility to take part of Melbourne suburb off-grid with solar + storage

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Mini-grids in Australia’s major towns and cities may be a reality sooner than many thought. Victoria’s Ausnet is to begin a trial with a solar and battery storage-based mini-grid in a Melbourne suburb.

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Victoria network operator Ausnet Services is to take part of a Melbourne suburb completely off grid, powered only with rooftop solar and battery storage, in a first-of-its kind trial in Australia that points to the speed of the household energy revolution.

There is growing interest in the use of  mini-grids in Australia, using local renewable energy sources to take remote towns and new housing developments either completely off the grid, or equipped with a “small” connection.main

But the planned trial by Ausnet – to be launched by Victorian energy minister Lily d’Ambrosio on Tuesday – points to the fact that mini-grids may also be used within major towns and cities as a cost-effective alternative to the century-old model of large centralised generators and expansive and costly networks.

Ausnet is to install between 3kW and 4.5kW of rooftop solar and 10kWh of battery storage on each of 14 homes in the outer eastern suburb of Mooroolbark, chosen because the homes are typically suburban, and because Ausnet has a network constraint it thinks it can solve with distributed energy (solar and storage), and because the network configuration means that it is relatively easy to take them off the grid.

The network operator will first monitor the production and consumption patterns of the 14 homes, before then inviting them to individually quit the grid, and see how long that lasts, and then to quit the grid altogether but share their solar and storage in an islanded network.

The 12-month trial will repeat this in several different seasons.

Ausnet managing director Nine Ficca says the “exciting” and “ground-breaking” trial is designed to demonstrate that homes with residential solar systems and batteries can generate, store and share renewable electricity with each other, and operate as a ‘mini grid’ via their local power lines.

“AusNet Services is excited to partner with the community to develop systems that may give consumers the choice to share their solar-generated electricity with their communities, potentially lower their bills and support the electricity network,” Ficca says.

The interest of the network, of course, is to remain relevant in a future that is dominated by locally generated solar and battery storage. Most utilities now accept that, within a few decades, around half of all electricity demand will be satisfied by “distributed energy”, and this means a complete revision of the energy market structure.powerlines_1

Networks are confident that they have a key role in this future, because it will make sense for communities to “share energy” and they will need wires to connect to each other. The future role of centralised generators and retailers is less clear.

Ausnet’s trial will build upon a recently completed three-year residential battery storage trial with homes in its network, which analysed usage and consumption patterns, and the potential returns on investment and tariff structures.

That study found that residential battery storage is not yet “economic”, but quick payback times may not be far off given the expected sharp fall in battery storage prices, which are expected to go down by half in coming years.

The most interesting aspect of that study was the conclusion that residential battery storage could offer as much, or even more, benefit to the network operator than to the consumer.

That’s because of the potential savings on network upgrades, and the ability to use battery storage to reduce and manage peak demand, provide stability to the grid, to provide power during outages caused by storms and other events, and to defer upgrades.

Some utilities are finding that the most effective means of saving costs for new developments, and for remote towns, may be to not build a grid connection at all, and provide a local network solution – or a mini-grid – instead.

Many utilities are trialing solar and battery storage in various situation, and particularly in sharing the output, including in housing developments Alkimos and White Gum Valley in Western Australia, and several trials in Queensland.

The Ausnet trial in Mooroolbark will be the first, however, to take a group of existing suburban homes completely off the grid. Ausnet says it is in talks with other towns and communities about similar projects.

“We’ve developed a control system that will monitor and manage energy flows within the mini grid,” Ficca says.

“This system will enable the energy that is stored in batteries to be shared between houses, based on the needs of the individual houses, the diversity of customer loads within the mini grid and the needs of the network.”

The trial will use JASolar JAP6 60  solar panels, Australian-made 5kW battery inverters from Selectronics and 10kWh batteries from LG Chem.

Most of the houses are owner-occupied.

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10 Comments
  1. Brunel 4 years ago

    Good to see quality AUS-made inverters being used!

    Maybe we should be trying to export inverters instead of low-end petrol cars.

    • MaxG 4 years ago

      Selectronic export them already. In fact, the SP PRO GO is rebadged by KACO Germany, and sold as their own. This means something, at least to me.

      Disclosure: I own a SMPC485 SP PRO GO 🙂 — connected to 12kW of panels and a 20kWh battery. :))

      • Brunel 4 years ago

        Surprising that a politician would not do a photo op at their factory.

  2. Phil 4 years ago

    This looks like a really smart test model with on , off , mini grid and even “as a fallback position” sometimes on grid options.

    And the panel , battery and inverter sizing is more realistic compared to some other trials.Especially if heating , cooking and cooling are efficient and looked at holistically with alternate energy options if needed.

    I would prefer to see 5kw of (unshaded) solar panels as a minimum though – more if shaded , after all it is Melbourne !

    It’s great to see the networks having an open mind about the possibilities.

    I think this is a huge opportunity at a later date (once baseline data is established) to trial and compare data of energy efficient appliances such as heat pumps , underfloor heating , inverter motor driven appliances such as fridges , reverse cycle air-con and modern insulation methods such as E-glass or window films for those without double glazing .

    I’m sure LG have exactly this in mind

    The availability of more than one option for heating , cooling and cooking based on sun days , weather and seasons could be very advantageous for an off grid situation

    • MaxG 4 years ago

      Lots need to happen in building — more of a passive house (PH) approach. I am owner-building what could become the first PH in QLD. Yes, double-glazed windows, air-tight — a 15th of the standard AU air change rate per hour… hence, my air/con is 2.5kWh for the whole house.

      • Phil 4 years ago

        Sounds like a fun project Max.

        Yes i’m surprised Qld has not gone for Double Glazing with E glass in new domestic builds. No doubt cost is the main reason.

        Keeping the heat out can become just as important as Heat In if it goes close to 40 deg Celcius.

        I went E – Glass single glazed in an Alpine area ( we get to minus 15 ) as the double glazing cuts the incoming low northern sun input down considerably ( by 70% versus 30% ) . We want that right through winter.

        Combined with air trap blinds and drapes at night it approaches double glazing (plus e-glass as most now have) performance for a reduced cost as well

        The other biz model is to massively overpanel your solar panels and use inverter air conditioning to cool instead of 6 or 7 star insulation performance (which is expensive up front ) . A very effective strategy with energy inefficient existing builds

  3. Ian 4 years ago

    This is a small trial involving owner occupiers with home solar and storage connected in a mini grid. How will the network maintain relevance, and produce an honest income in this situation?

    If the off grid trial is successful there would be no need for a network provider. Presumably all the elements of the mini grid would be owned by the households themselves.

    • Phil 4 years ago

      I think it’s an attempt to see if it’s feasible to repurpose the poles and wires , which the consumer does not own , into a mini grid . The consumer only leases the grid and the off grid tech , installation and maintenance expertise of the provider.

      It’s an interesting project as it will expose the many permutations of peak and average loads , demand , climate , seasons , holidays and householder needs variations due lifestyle and appliances used.

      Your right , if the costs are too high you might as well go off grid. But how to do that if you don’t have the expertise ?. And is it legal and will your insurance cover an incident such as fire , fusion i.e lightning direct strike or emp surge into your panels ?

      We are talking suburbia here , not an off grid regional situation where necessity is the priority , not so much cost. Although it often works out cheaper if you DIY !

      This project should go some way to answering the questions before they are asked.

      Based on my calculations if the provider is not greedy it should come in at 26 cents per Kilowatt hour (ex gst) assuming $5k for 4.5kw solar panels and assuming average 20kwh per day consumption . Plus the cost of a genset or grid connect as backup , both of these could be fully funded by what you would pay for the poles / wires / smart meter rental ( Victoria) daily access fee anyway.

      These are based on a typical 5% home loan interest rate and a cost of $16k for the solar panels , batteries and Off grid inverter/ mppt charger.And a full “refresh” every 15 years.

      The solar panels should be around $5k based on REC’s rebates so your only paying full price for the batteries and combined off grid inverter/ MPPT solar charger.

      If they are greedy you can double that . In which case you might as well go off grid and pay someone to do it for you much cheaper.Or pay effectively 50 cents per Kwh

  4. JeffJL 4 years ago

    I sincerely hope that they do not mean that they will be disconnected from the grid and it is just that the area will provide 100% of their electricity needs.

    The requirement to provide 100% of their electricity needs will require significant oversupply of PV at times. What a waste if this is not fed back into the grid to reduce FF use in other areas.

  5. Val Kay 4 years ago

    Does anyone know how they plan to heat the houses in winter? I could go off-grid myself except for that.

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