My understanding is a system can be installed, but it can’t be electrically connected to the grid until such time the connection is approved. The agreement response usually only takes a few days from the installer lodging the application. In Tassie, it is clearer the process as TasNetworks approves the connection (Form CS20) and then lodges a electrical work request with the metering company for the connection to be made (either through physical meter replacement or my updating existing meter firmware). Both documents are issued to the installer and the customer.
Energex has been knocking back connection requests where a(n additional) PV system on the local distribution network is likely to cause issues. While this in the past has principally been on upflow issues (where the flow in a local distribution network tried to push flows to the higher voltage network - which I understand would cause PV systems/inverters in an uncontrolled environment to keep pushing the voltage higher to try to overcome the flow ‘barrier’).
The impact of higher voltages due to a number of local PV systems all trying to export and this all competing for a higher voltage to push the PV energy to the grid) has particularly become an issue in local networks where PV is near network capacity. The result has been to lower the network voltage from 240 to 230V to counteract this effect. It is also plausible that in the future a reduction to 220V may be considered if voltage issues reoccur.
I also understand that Energex looks at inverter capacity/maximum rating rather than maximum potential PV cell output. As inverters can handle +20% and also some may installer PV cell outputs than their inverter capacity (and could theoretically add additional panels in the future without changing inverter), using inverter rating is the logical way to assess current network limitations and feasibility of new PV connections.
Also looking at the graphs, Queensland appears to have the lowest mean voltage of the four and all voltages less that 256V.
high grid voltages are not only due to PV systems exporting, as the voltage is high overnight as well, and on local area transformer feeds with zero to very few systems connected, day and night.
Firstly we do not know the sample or statistical basis for each set of results, other than they are a snap shot of suburban values. How many suburbs, how many cities and towns, how many samples? If too few the sample is insignificant and likeLy unreliable.
Secondly the basis of the sample was to assess compliance with the national standard of 230V. The graphs illustrate one thing. Supply is not being regulated around an average or mean of 230V. The approximate mean in each graph is between 245V and 250V.
It is never, not even close to the nationally agreed and as FAIK Qld legislated standard of 230V. That is the point of the statistical presentation. It is a poor excuse to say it is all OK because most of the time the voltages in the samples are just within the upper 10% limit of 253V.
Of more relevance per the Qld State Govt.
From 1 July 2020, our electricity networks will aim to operate within a ‘preferred operating range’ of 230 volts +6/-2%. This range is set out in AS 61000.3.100 (Steady state voltage limits in public electricity systems). The preferred range aims to optimise the network to ensure electrical appliances operate more safely and efficiently.
On which basis the upper limit of supply is 243V and very clearly not met according to the urban samples for Qld or the other states. The position of the four states as reported by the ABC and UNSW is far from compliant to AS 61000.3.100. It is also not defensible IMO!
Here’s some hope for pensioners…well if you live in Sth Australia at the moment. SA are instigating a free Solar Panel system pilot program for 1,000 lucky Concession Card holders. They only have to forgo their State paid power and Cost of Living concessions when they get the offer. From the following article the “Concessions that households would have to give up include the $215.10 per year Cost of Living Concession and $231.41 per year towards their energy bill”.
Would the giving up of $400 odd in subsidies be enough to encourage you to take the offer up? To be honest I’d give mine up in a heartbeat to access the “free system” if I was ever to be invited to such a scheme.
The Australian standard referenced by legislation & regulations of states and territories does not use ‘mean voltage’, but sets out the preferred median voltage (V 50% ) range and places limits on the voltage spread (V 99% - V 1% ) with respect to steady state voltage variations in medium voltage networks.
Looking at arithmetic mean values of voltages is meaningless in this context.
The questions to ask are:
How does the median value in a part of the grid compare to the standard’s 230V ?
How often does the voltage go above 253V ? and if it is more than 1% of the time then that part of the grid is non-compliant.
How often does the voltage go below 216.2V ? and if it is more than 1% of the time then that part of the grid is non-compliant.
The UNSW study and other studies have found non-compliant parts of the grid (voltage too high) where there is no rooftop solar feed-in occurring.
Where ‘low voltage part of the grid’ is the nominal 230V supply(single phase 230V, three phase 400V) and not the ‘medium/high voltage supply’ which operates at several voltage ranges (11kV, 22kV, 33kV, 66kV, 132kV).
A big grid connection to come online in Qld later this year after the Wandoan big battery received it’s registration from AEMO. 100/150 MWh battery is owned by Vena Energy Australia and will be run on behalf of their client AGL
Not picking on GIP but why did it take a multinational to build this system when it could have been an Australian benefitting Australian owned business. Now further money to flow out of Australia. All of our renewable energy infrastructure seems to be quickly becoming all foreign owned…we are too slow on the uptake.
Don’t mention the “Black Box Flight Recorders”, or all the other fantastic Aussie inventions, which all went overseas due to the failure of Australian Governments and Australian companies to support them.
A battery that may be coming to us soon. It is larghe, too large for small scale use eg Cars and probably homes, but perhaps the perfect answer for overnight and long lasting loads in towns and larger communities. The battery uses iron and conversion back and forth to rust. It is advertised as having an almost unlimited lifetime and promises up to 100 hours of backup power when needed.
Gets my vote of confidence. A group of like minded nerds were discussing this technology 15 years past, and wondering why it had not found favour for static applications.
It’s not the only candidate for large scale grid storage. Just refreshing to hear work on batteries that do not use lithium is alive and progressing.
Around 2012 the hydrolysis problem that held back development was largely made unimportant through a simple addition of Bismuth Sulfide to the battery water solution:
March 2021 Qld government announced more community batteries
“network-connected batteries in Hervey Bay, Bundaberg, Townsville, Yeppoon and Toowoomba and will collectively store up to 40MWh” https://statements.qld.gov.au/statements/91787
This “Sun Tax” on solar exports is getting closer, of course industry is saying that this won’t be a big effect on customers. One distributor says the export that occurs between 4pm and 9pm will get the best reward at 2.19 c/kWh. My battery is used mostly between those times to limit my draw from the grid, I wouldn’t see this as a benefit at all. Here are some links including the information about AEMC’s determination.
The following link is a very worthwhile read into the lack of justification for the tax. I like the statement "Gray says the other justification for solar export charges – to encourage more electricity self-consumption during the day and exports in the evening – is also an unrealistic outcome in the current market.
“How many working families will be able to shift their main electricity use to the middle of the day and afford a battery so they can export at night?” she asks."…Indeed who?
AUSGRID’s laughable 2,5000 kWh per year limit would be exceeded in my case within a 2 month period at the most and generally within 1 month. One other is citing anything over 5 kW in any hour will see the tax being levied. Again during the day this would be surpassed nearly every hour by our household. Another is saying set your export limit during peak to 1.37 kW per hour to avoid the penalty. Nothing about this is good for consumers, it certainly benefits the large generators in the power industry.
