Ergon takes steps to manage booming rooftop solar uptake

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UPDATED: Regional Queensland network operator rolls out technology to allow more rooftop solar power to be exported to the grid, without disrupting supply.

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One Step Off The Grid

UPDATED: Regional Queensland network operator Ergon Energy is taking steps to get ahead of the solar curve, with the roll-out of technology it says will allow more solar power generated on home and business rooftops to be exported to the grid, without disrupting supply.

The technology, which will be provided by a local outfit called Satcom Solutions, is being installed to manage voltage swings on the network – a problem that has long existed for grid operators, but which they argue has been exacerbated by the uptake of rooftop solar.

Exactly what portion of a network’s voltage problems are actually caused by rooftop solar is difficult to pinpoint – but if any network was going to have a problem with it, Ergon would be a contender, with more than 140,000 home and business PV systems connected to its grid.

Traditionally, networks have managed the problem of voltage surges in areas of high solar penetration by “tapping” the voltage at the sub station levels, which has been seen as an inefficiency and costly solution.

At a regulatory level, standards have been imposed that cause solar inverters to switch off at a certain output level, which has been criticised for robbing customers of power and savings, and potentially pushing consumers off the grid.

And in some networks, there are strict restrictions on the overall size of the PV system that households are allowed to install.

The installation of statcoms at a poles and wires level is considered to be an alternative approach to regulating voltage that is more efficient and consumer friendly – although according to a number of experts RE reached out to, it is not necessarily the best or most economic one.

Addressing the problem at a household level, both with smart inverter technology and increased self-consumption using battery storage, are also viable options.

Nonetheless, the expert opinion was unanimous in saying that Ergon – which appears to have been doing its homework on the issue – should be applauded for “getting ahead of the issue” and moving beyond the sub-station to do so.

In a statement on Monday, Ergon said the voltage stabilising technology – or low voltage static synchronous compensators, or “statcoms” – had already been installed in Mossman, and would continue to be rolled out to other parts of the network.

The project has been estimated to cost $2.8 million, which will cover the cost of embedding the LV statcom technology across the Ergon Energy and Energex networks.

“Statcoms regulate the voltage on sections of the network where they are installed, enabling more households to feed solar power into the grid and managing peak load voltages also,” said Ergon’s manager of intelligent grid and new technology, Michelle Taylor.

“While statcoms are not a new concept, Ergon’s innovative application of the technology uses small-scale statcom devices to help manage the low-voltage network.

“Ergon’s technology innovation engineers successfully delivered a proof of concept for the statcom equipment in 2014 and successfully trialled test versions of the technology in 2015. This device can now be a new tool in the tool-box for solving network issues,” Taylor said.

RenewEconomy asked Ergon on Monday how much the roll-out was costing the newtork operator, and whether other – perhaps cheaper – alternatives had been, or were being considered.

Here’s the network’s emailed response:

“Ergon Energy considers Statcoms as another tool for responding to rising voltages …They may not always be the most economic response in every situation, but they can be cost-effective in carefully targeted locations.

“…As with all network investments, we consider a broad range of solutions including traditional network upgrades (for example line and transformer upgrades) and non-network alternatives (for example phase balancing, transformer tapping, customer inverter changes and low voltage regulators).

“These solutions are assessed in terms of their benefit and overall value to customers and the network (their net present values) and solution that provides the greatest benefit is chosen.

“For this reason, although we’re deploying LV statcoms through this project, LV statcoms won’t always be the ideal solution to resolve network constraints,” Ergon said.

“At this stage batteries are not viewed as a cost effective solution but we continue to watch this emerging opportunity.

“As batteries become more affordable, the voluntary uptake of battery storage, particularly when coupled with rooftop solar, is a good thing for the network and our customers.

“In some instances it will help reduce the need for network investment and ensure that the energy generated by rooftop solar is used closer to the point of generation.

“Does it undermine the need for investment in these technologies? No. The continuing shift toward distributed energy resources like rooftop solar and batteries will place greater onus on the need for a flexible distribution network.

“Solutions like LV statcoms will help to provide this flexibility on the low voltage network and help to manage constraints as close as possible to their source.”

This article was originally published on RenewEconomy’s sister site, One Step Off The Grid, which focuses on customer experience with distributed generation. To sign up to One Step’s free weekly newsletter, please click here.

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19 Comments
  1. MaxG 3 months ago

    Like the adoption Euro emission norms, Australia has failed to adopt 230V as nominal voltage. AS/NZ 3000:2007 does clearly state in clause 1.6.2 part [c] that the nominal voltage is 230V.
    In my case Energex has done bugger all to correct the problem of correcting the 260V regularly occurring in my street.

    • john 3 months ago

      Evidently they are going to go to 230V some time soon.
      And if you have 260V it would destroy most of your equipment.

      • Shilo 3 months ago

        I am with ergon and it sits around 247 to 249, with many peaks at 260.
        I have a long list of stuff that dies early.

        • john 3 months ago

          The fixed state transformers may need a tap reset.
          Contact Ergon and they will put a data logger on your switchboard.
          Sometimes those closest to the transformer will have high Voltage so those at the end of the street do get adequate voltage.
          If you have old 6 mm copper and PV then you need to have the aerial connection to your fascia upgraded.
          The wiring to your switchboard upgraded to larger wiring will lesson the voltage rise or drop.
          Contact your electrician or a solar installer for advise, he may have a data logger the usual cost is $150 a month IIRC.

          • Shilo 3 months ago

            Thank you john, all was checked out a few years ago with a data logger and they state they have plus or minis 10% on 230-240v

      • MaxG 3 months ago

        Where is the evidence?

        • john 3 months ago

          Max from Ergon Energy site
          https://www.ergon.com.au/network/network-management/network-infrastructure/230-volt-transition

          The Queensland Government recently confirmed a change in voltage from 240 volts to 230 volts across the state.

          Note: On this webpage when we use the term ‘240 volts’ we mean 240 volts (+/-6%), and when we use the term ‘230 volts’ we mean 230 volts (+10/-6%).

          • MaxG 3 months ago

            Thank you!

            The most interesting bits are:

            Queensland’s Electricity Regulation was amended on 27 October 2017 to mandate a transition to the 230 volt standard in Queensland.

            By 26 October 2018 our network electricity supply voltage limits will transition from 240 volts to 230 volts as per AS 60038.

            From 1 July 2020, we’ll maintain network supply voltage within the preferred voltage range set out in AS61000.3.100 (Steady state voltage limits in public electricity systems). This sets an 8% ‘preferred operating zone’ (between 225 and 244 volts) within the allowable range (between 216 and 253 volts).

          • Aerial Fencer 3 months ago

            Do you think Energex has gone to the 1000’s of transformers in the network, turned them off, changed the taps and than turned them back on again?

          • john 3 months ago

            It could be done at the substation level just drop the HV from nominal 11000 down a bit, or reset the taps as need be.
            Possibly back to 10500

    • john 3 months ago

      Max from the same page this link.
      Read more about International Standard IEC/AS61000.3.100
      http://besaust.com.au/wp-content/uploads/20120215-ICHQP-2012-Steady-State-Voltage-final.pdf

  2. john 3 months ago

    I read this line.
    The project has been estimated to cost $2.8 million,
    It is going to cost that much to simply give a permit to put a solar system on some persons roof?
    Total rubbish.
    A large system installed was resisted to 3.2 kw per phase come on this is rubbish.

    • Andy Saunders 3 months ago

      No, the way I read it, that is the cost for a rollout/installation of statcoms throughout their network.

      But as these are only tangentially related to solar PV, I’m unsure of the link. VAR controllers like statcoms are useful at the end of long lines with high-reactive-power loads, to help stabilise/correct the resultng voltage droop. But as solar PV exports generally raise voltage I’m unsure what the connection is.

      • MacNordic 3 months ago

        They should take care of voltage peaks and lows via their capacitors, absorbing surplus power/ feeding in in case of drops in the voltage, thus smoothing the voltage profile.
        Some Satcoms can apparently be connected to a power source (battery) to enable longer term reactive power in cases of low voltage.

        ABB says the following:
        “Electrical loads both generate and absorb reactive power. Since the transmitted load often varies considerably from one hour to the next, the reactive power balance in a grid varies as well. This can result in unacceptable variations in voltage, including voltage depression or even voltage collapse. Like SVC but faster, STATCOM continuously provides variable reactive power in response to voltage variations, supporting the stability of the grid. ….
        Installing a STATCOM at one or more suitable points in a grid will
        increase power transfer capability by enhancing voltage stability and
        maintaining a smooth voltage profile under different network conditions. Its ability to perform active filtering is also very useful for
        improvements in power quality.” [source: https://new.abb.com/facts/statcom%5D

        • Aerial Fencer 3 months ago

          The STATCOMS are used to improve power factor on a line, reducing current, thus reducing voltage drop. Electronic inverters already have great PF correction. The statcoms will help for voltages on long LV feeders that have big inductive loads on them (e.g. big water pumps). They will do very little for overvoltages in high PV areas

    • MacNordic 3 months ago

      Nothing to do with permits – at least not directly.

      In long distribution grids with both loads and generation connected, it is difficult to always keep voltage and frequency within prescribed levels.
      Just think of a dead end road, where you are tasked with controlling access.
      While you will only let in so many vehicles as not to overload the capacity of the road, you cannot control the ongoings down the lane: some drivers will insist to park or turn in the most unfavourable places of the road, impeding other cars. Similar, some local might decide to open up a field for parking, giving much more space on the road (load addition). The other might decide it is a good day to park all of his car collection on the side of the road, decimating the available space for parking (generation feed- in).

      While you will eventually notice the changes at your position, the contenders might already be near meltdown further down the road (voltage/ frequency out of band).
      The Statcoms are basically other guys looking after the traffic flow all along the road, smoothing out loads and feed in via capacitators, keeping everything orderly: keeping voltage within the prescribed bandwith by taking up peaks and feeding in during lows. Similar can be done with frequency.

      Now, if you have the other guys looking after the cars (voltage) and traffic flows further down the line, you can allow more cars in, as everybody parks halfway decent (your permits: more generation can be allowed down the line).

      Hope this helps explain it somewhat!

  3. solarguy 3 months ago

    Look I could be somewhat wrong here, but just put excess solar generation into grid scale batteries. Kill two birds with one stone!

  4. Francis Young 3 months ago

    So the renewable remedy to electricity price rises caused by gold plated poles and wires is more gold plating of the grid. Nice.

  5. Antony Piccinini 3 months ago

    So, large amounts of solar PV are causing voltage rise for NSPs (Network Service Providers)? These are the possible solutions for an NSP. Let me guess which one gets up?
    1 – Make all solar inverters absorb reactive power in proportion to the voltage effect of their real power, so as to negate their own voltage rise – say 0.95 absorbing is a good “rule of thumb” power factor. Simple to implement and cost = negligible. Nothing in it for the NSP though = unlikely to happen.
    2 – Even better, make all solar inverters capable of implementing voltage control mode, adjusting their own reactive power output to control their own terminal voltage. Customers would actually end up with improved power quality! Most of the good inverters can do this already and those that can’t will be able to pretty quickly once it’s made a requirement. Cost is again negligible but nothing in it for the NSP again, so also unlikely to happen.
    3 – Hang on though, NSPs could spend heaps of money on STATCOMs off the back of this. That would increase their asset base, on which they earn a regulated return and the cost will just be smeared across all customers (again!). They would look like forward thinking companies enabling the smart grid technologies of the future… whatever that means. And the regulator is of course too dumb to notice… if anyone asks they can just blame the renewables. I think we have a winner!

    This, and thousands of conversations like it, explains the blow out in electricity costs over the last decade. I feel sad for my country…

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