Thread: Future of the Australian Electricity Market

So far the $1/minute overtime charge seems to working is working surprisingly well but as you say as more users come onto the system there will be more people with $$ to spare won't care.

Originally Posted by Warb

I would also assume that companies with car parks would also provide charging stations for their workers. In LA I'm sure I saw rows of sunshaded parking with PV roofs and charging for the cars underneath.

Some of the newer remote faster/larger NRMA chargers going in over east are covered with PV panels, and contain a large battery and also a diesel back up generator.

Thanks to Bob and Warb for the EV input. It brings home the extra capacity that will be required down the track for the Electricity Market. Clearly there is a long way to go for the development of the market. It is very early days.

Regards
Paul

Originally Posted by Bushmiller

Thanks to Bob and Warb for the EV input. It brings home the extra capacity that will be required down the track for the Electricity Market. Clearly there is a long way to go for the development of the market. It is very early days.

Regards
Paul

It is a big adjustment. More worrying (?) is that as Bob says, most people will charge their EV's overnight, and we're already discussing the overproduction of solar through the day and shortfalls at night. Overnight EV charging will simply add to that problem, and generation-->storage-->storage(EV) chains are inherently lossy.

"Early days" is when we should be looking to set up a system for the future....

Originally Posted by Warb

It is a big adjustment. More worrying (?) is that as Bob says, most people will charge their EV's overnight, and we're already discussing the overproduction of solar through the day and shortfalls at night. Overnight EV charging will simply add to that problem, and generation-->storage-->storage(EV) chains are inherently lossy.

"Early days" is when we should be looking to set up a system for the future....

Furthermore, having solar panels with a home battery won't improve that situation because the smallest car batteries are 3-4x the capacity of a home battery.

Originally Posted by FenceFurniture

Furthermore, having solar panels with a home battery won't improve that situation because the smallest car batteries are 3-4x the capacity of a home battery.

Hopefully, as Bob says, most people will top up their battery every day/night so that domestic/EV battery discrepancy shouldn't be too much of an issue, especially if they can get a good charge at the weekend. Most city/town dwellers don't travel excessive distances on a day-to-day basis, especially now that working from home is such a big thing (temporarily?).

Those city dwellers in apartments won't have access to domestic PV, so they're the people who will need overnight charging or daytime charging at work, and if they're reliant on overnight charging then......

If we were proactive, I imagine we'd be insisting that all new developments had powered carparking spaces, and we'd be replacing parking meters with trickle chargers and so forth. After all, if an EV was connected to even a tiny power supply (10amp domestic or below) EVERY TIME it was parked, with the exception of occasional long journeys I'd imagine 99% would never need anything more. This is why I don't understand the installation of city charging stations in the form of servo's, surely omnipresent small supplies are better than sporadic huge ones?

Originally Posted by FenceFurniture

Furthermore, having solar panels with a home battery won't improve that situation because the smallest car batteries are 3-4x the capacity of a home battery.

More like 5-6x

BUT
The need for most city users to fully recharge every day is rare.
In 6 months EV use, I have used 2118 kWh of charge, 88% (1863 kWh) of which has been charged at home
This works out to just 10 kWh a a day so at say a 90% round trip efficiency (most decent battery systems can achieve this), if I had say a 13 kWh hour battery I could "in theory" be away from home all day but could full recharge my EV from the home battery at night.

In practice
- some days the EV uses more than 10kWh, other days it might use less
- some days your PV system may not produce 10kWh of battery charge eg weather or home use.

However, one rarely needs to recover absolutely every bit of eV battery charge in one go every time one charges, so what if you only charge from the home battery to say 70%, or do not even charge at all - it can be made up on other nights. This approach results in minimal draw from the grid at night.
My brother and his wife have this setup and they have 2 EVs. He's retired and is at home most days so he can charge is car during the day. Excess solar goes into a 13kW battery to help charge his wife's small eV at night. She does very few km in her car (ie works and back) so only needs 2-3kWh of house battery each day to cover her travel and the rest of the solar usually covers his car and their homes needs at night.

I don't have a battery and these days I am often away from home during the day.
When I come home I sometimes forget to plug in but I'm getting better at remembering - its dead easy as the EV socket plug and charger are right next to my front door.
During winter with reduced overall solar production coming home after 4pm doesn't add much charge to the EV so at best I estimate I was getting at best about 50% of my EV charge from solar during winter. Because I'm not using ACs in winter at least virtually all of the solar output can go into the EV.


With summer approaching the extended daylight means there are many days where it's possible to recharge both my car and power my home (2 ACs) mostly from solar.
Below is one example for a typical 36º summer day in Perth.
The graphic shows power produced, consumed and exported/imported, and shows I used solar to power 75% of my total requirements
The graphic also shows I still exported 5.8 kWh so if I had used a battery my grid usage would have been reduced to ~10% of total usage.

Y axis scale needs to be multiplied by 4 to show proper kWh readings
The gap between the red and green lines shows my base power use ~700W which includes a small bedroom AC that stayed on all day.
The gap between the green and blue lines shows the eV charging between ~9 and 4pm at about 2.5kW for a total of 17.5kWh (ie almost double my average) I had to manually set that power level
The gap between the blue and purple line shows a second larger AC in use in the family room for about 3.5 hours
eVCharge.jpg

There are apps that link between PV systems car chargers to maximise solar EV charging. My system is currently not compatible with my charger although it is apparently under development.

It takes some getting used to but given the cost difference between solar charging and mains charging is a whopping 3c/km Im not phased when the EV draws from the grid.

Originally Posted by BobL

It takes some getting used to but given the cost difference between solar charging and mains charging is a whopping 3c/km Im not phased when the EV draws from the grid.

Veering slightly away from the electrickery industry, the last time I calculated the cost of running an EV the accepted norm was 0.2kWh/km. For us that means that at off peak rates it would cost about 8c/km to run an EV (if we had no solar!). That compares to around 11c/km for a hybrid Rav4 at present fuel prices.

As I have little doubt that our next "family" car will be electric, can I ask (Bob) if the 3c/km price is down to far cheaper power prices than our 40-odd cent off peak (55c peak!) rate, or have EV's improved beyond the previously accepted 0.2kWh/km average?

Originally Posted by Warb

Veering slightly away from the electrickery industry, the last time I calculated the cost of running an EV the accepted norm was 0.2kWh/km. For us that means that at off peak rates it would cost about 8c/km to run an EV (if we had no solar!). That compares to around 11c/km for a hybrid Rav4 at present fuel prices.

As I have little doubt that our next "family" car will be electric, can I ask (Bob) if the 3c/km price is down to far cheaper power prices than our 40-odd cent off peak (55c peak!) rate, or have EV's improved beyond the previously accepted 0.2kWh/km average?

0.2kWh/km is about average across a range of EVs ,but it varies widely and most of the published figures are significantly underestimated and an immediate discount of at least 10% is required..
At the recent Perth EV show I was disappointed in how inefficient almost all the new vehicles were.
Of those on display with only the Mini Cooper and the small BYD were significantly sub 200. Some of the larger EVs were 250+.

Teslas are by amongst the most efficient EVs. My "dual motor" high performance Tesla Model Y (525HP on tap) gets a real world 165 Whr/km and if I go easy on the accelerator I can get ~150 Whr/km. A single motor Model 3 Tesla (their most efficient vehicle) driven relatively conservatively can get 140 Whr/km. I bet if my wife was still here she could get this on my EV.

Im paying 31c at all times but can get it much cheaper off if I go for a peak off peak rate

The Smart Home Plan is 16 to 58c

There's an EV scheme that offers 8c in the early am, and 22-50 otherwise. My BIL (Tesla single motor Model 3) uses this and says his weekly commute costs (was a full tank of fuel) is something he just doesn't think about any more.

All this is courtesy of guaranteed/reserved price gas the WA government established about 15 years ago.

Buy back is 10c between 3 and 9pm, and 2c at other times - ie might as well use it !

Interesting online ABC article posted this morning Community pushback against renewable energy projects could see Australia miss its emissions targets and climate goals - ABC News
the gist seems to be, the proposed developer of the overhead power line, AusNet, will construct the line in a way that the height of farming machinery used under the line will be restricted to a maximum of 3.0m.

while the story is couched in terms of being a roadblock to Australia's renewable push, it strikes me that increasing the height of the pylons would lift the line further off the ground allowing taller machinery to be used under the lines.

It also strikes me that undergrounding the lines -- as many farmers seem to prefer -- would be worse, as underground lines would prevent the area occupied by the lines being farmed by tilling.

I'm envisioning that to be cost effective, lines installed underground would require something the size of a D12, or even bigger, dozer fitted with a ripping hook. Lines installed by ripping a trench would sterilise even more farmland than installing overhead lines with an "electrical safe" clearance of (say) 5 metres. Ripping is how rural fibre optic cables were installed from the 1980s.

Originally Posted by ian

....construct the line in a way that the height of farming machinery used under the line will be restricted to a maximum of 3.0m.

while the story is couched in terms of being a roadblock to Australia's renewable push, it strikes me that increasing the height of the pylons would lift the line further off the ground allowing taller machinery to be used under the lines.

It also strikes me that undergrounding the lines -- as many farmers seem to prefer -- would be worse, as underground lines would prevent the area occupied by the lines being farmed by tilling.

I'm envisioning that to be cost effective, lines installed underground would require something the size of a D12, or even bigger, dozer fitted with a ripping hook. Lines installed by ripping a trench would sterilise even more farmland than installing overhead lines with an "electrical safe" clearance of (say) 5 metres. Ripping is how rural fibre optic cables were installed from the 1980s.

3m is a ridiculously low cable, even the smallest "real" agricultural machinery wouldn't go underneath! My 100hp John Deere was 2.5m tall, and larger headers can be up towards 5m. On hilly grazing land, where no big machinery goes, 3m might be OK (folded up spray rigs are the only thing that might cause a problem), but in such areas the cables are normally taken from hill to hill so "height" is relative!

Buried cables are much easier for farmers. Other than deep tillage, which rarely goes below perhaps 50cm and mostly much less (20-30cm), a >600m bury depth won't trouble many farmers. Unfortunately burying power cables is expensive!

Regarding buried fibre, my farm had the main fibre that served Central West NSW running under it, and the "new" fibre they put it perhaps 10 years ago running parallel. When they originally put in the old fibre, they didn't fit a metal trace and instead used transponders at strategic points with straight lines in between. Unfortunately (though predictably) the transponders failed over time, and now many don't work. The result is that they have no idea of the exact path of the fibre. On my farm they could find it on one side of the valley, and halfway up the hill on the other side, but across the valley floor it was largely guess-work! It caused them much stress when they tried to run the new fibre parallel to something they didn't know the location of! The new fibres have a metal tracer installed with them, so it can be tracked exactly.

As a farmer, there is no compensation for an underground cable being installed. On an ongoing basis that's perfectly OK, because there is also no impact. However at the time of installation, any livestock has to be removed for the duration of the work, crops are destroyed, pipework etc. is unusable until repaired/replaced (and afterwards there are joints that can leak). They tell you that they will repair fences, but they simply cut and then stretch the fences and rejoin the wires, meaning they are now over tensioned. With the eye watering cost of rural fencing, it is painful to see the shock absorbing corrugations of your new fence being pulled straight by a contractor over-straining the wires and bunging in a Gripple. If you fight you can get compensation for crop damage, but it's a struggle (though to be fair, some "farmers" don't help the cause by claiming that what was in reality worthless "un-improved pasture" was, for compensation purposes, race-horse quality lucerne).

There can also be issues with weeds, as seeds picked up on one property are transported down the line by vehicles, tools and boots.

So the problems for both underground and overhead cables are all very real, especially when the work is done by people who don't care and are working to the smallest budget possible.

A couple of "industry insights" (I work in fibre optic systems and power networks).....

First, the 3m doesn't mean the height of the overhead cable off the ground. HV conductors have a minimum "safe approach distance", which varies with voltage (e.g. 132kV, 330kV, etc.). I don't have my Ausgrid or TransGrid network rules books handy, but they would have allowed possibly a further 6m or more above the 3m max. machine height that was mentioned, so conductor would actually be at 9m minimum. Second, you don't just plough in HV underground cables. Most underground installs are in duct (grouped together in a trefoil for the three phases), typical drum lengths for the larger cables rarely exceed 700m, so that means a joint bay every 500-700m for the sections to be joined together. Longer routes would be trenched with the cable laid into a sand bedding. The backfill into the trench has to be of a known thermal resistance, usually a mix of sand/cement, or in metro areas the ducts carrying the cables are embedded in a soft concrete mix (FTB - Flowable Thermal Backfill) which has a uniform and known thermal resistance to ensure max conductor temperature of the cables isn't exceeded under design load. I work with fibre optic systems strung up the middle the the conductor trefoil to sense temperature, from which we can calculate the conductor temperature in the cable. This must not exceed 90C under full load or extended service.
I worked at Optus while they were building their initial fibre network around Australia, most of it ploughed in behind a D9. Since they are non-metallic, the fibre cables have a warning tape containing a fine wire installed above them, plus transponders, but both can prove very elusive when looking for the stuff. It doesn't help that the as-built drawings from Leightons (the contractor) were often a work of fiction. Regarding contaminated soil, I do remember one spectacular case that spent years going through the courts - Leighton brought in some topsoil from elsewhere for remediation works across a farmer's paddock, dressed it all nicely, and went on their way. A few months later a broad purple stripe appeared across the paddock following the trench line; the imported soil was contaminated with seeds of Pattersons Curse. Ooops.

There you go - for TransGrid (NSW):

safe.png

They would be working from the Mobile Plant guidelines in this case, and restrictions also depend on whether an observer is available (and other measures) to control the hazard. 330kV overhead lines = 6m (my memory may not be shot after all).

Originally Posted by Mr Brush

There you go - for TransGrid (NSW):

safe.png

They would be working from the Mobile Plant guidelines in this case, and restrictions also depend on whether an observer is available (and other measures) to control the hazard. 330kV overhead lines = 6m (my memory may not be shot after all).

Thanks Mr.B


I have pointed out in the past that some idea of voltage can be gleaned from the distance the three phases are apart. Similar clearances apply downwards and this must be to the top of the tallest machinery. I hadn't realised there was a two tier system for machinery.

When I first did my training, quite a while back last century , we were told of a farmer who complained that he was getting electrical shocks from the overhead transmission lines. When it was investigated, it turned out that he had bought a new state-of-the-art tractor that was large enough with the air-conditioned cab to come inside the safety clearances and he was experiencing electric shock from induced voltage. It may have been safe while he was still in the tractor, but not so good if he decided to exit while under the lines.

Regards
Paul

Originally Posted by Mr Brush

...... they would have allowed possibly a further 6m or more above the 3m max. machine height that was mentioned

3m is still totally insufficient for modern agricultural machines. As I said, my "little" 100hp John Deere was 2.5m tall, before adding the various antenna and warning beacons on the roof or lifting the bucket on the loader. My friends Steiger is basically 4m to the top of the cab..

Originally Posted by Mr Brush

I worked at Optus while they were building their initial fibre network around Australia, most of it ploughed in behind a D9. Since they are non-metallic, the fibre cables have a warning tape containing a fine wire installed above them, plus transponders, but both can prove very elusive when looking for the stuff.

When the Telstra guy came out to locate the fibre across my front three paddocks when we were modifying the irrigation pipework, he stated that no copper trace was laid with their original fibres. Of course, as he worked for Telstra his info may have been incorrect! However when the guys came to install the new fibre they also had massive problems finding the old one!

Originally Posted by Mr Brush

A few months later a broad purple stripe appeared across the paddock following the trench line; the imported soil was contaminated with seeds of Pattersons Curse. Ooops.

They really never think about the consequences of their actions. One lot decided they were fed up with weeds around their installation (I suspect it was telecoms) so they bucketed out a pelletised long-life residual herbicide. When it rained it washed down the hill into a vineyard, killed acres of grapes and olive trees and left the ground unusable. Cost a fortune in compensation.