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Daniel Andrews solar panels initiative

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Knobby22 said:
It's the local transformers that won't handle it. Also the mess all those digital outputs will make to the electricity waveform. Realistically it's not possible without major upgrades.
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Ahh Ok, got it. Generating the correct waveform is no easy task I take it.
 
sptrawler said:
The problem is, not what to do with excess power. The problem is the unstable power renewables produce.
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Yep, well I thought part of the idea of pumped hydro was to smooth out the volatility with charge/discharging but presumably it doesn't solve the problem of compatibility.

Crickey, we may be told to leave lights on during a sunny day
 
PZ99 said:
Ahh Ok, got it. Generating the correct waveform is no easy task I take it.
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Frequency control is the most important aspect of generation, too much generation frequency goes up and vice versa.
Electrical equipment is very sensitive to frequency, motor speed is directly linked to it, current draw is affected by it.
The generators connected to the system are locked to it, if that lock is broken, you get pole slipping which causes massive load swings as the generators go in and out of phase.
This is the problem that smurph talks about, the whole grid works in balance, to do that you need inertia to absorb over generation and take the hit from under generation.
It is hard to appreciate the issues, unless someone has worked in the power industry, or has an electrical background.
 
In simple terms, if the frequency falls, electrical motors slow. As they slow they draw more amps, which causes heat and they burn out. So your fridge and aircon burn out.
If the frequency goes high, the generators on the system reduce excitation on the generators, this weakens the magnetic link they have to the system.
Then when the link is overcome by the prime mover, it slips out of synchronisation, then it starts to go in synch then out of synch.
Which makes it grab heaps of load, then toss it, which means the other plant on the system has to pick it up then reject it.
It isn't pretty, Ive seen it once and it isn't funny.
 
HelloU said:
train, ship, mines or elsewhere? Agree, when you flick the breaker to parallel and they are not quite sync'd it is a thing you learn from.....
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Commissioning generators in regional country towns, that aren't on the interconnected grid.
 
Im currently running a 5KW system with a tesla power wall 2 battery . I have had the solar installed since 2015 and the battery since May this year. The tesla allows me to monitor my usage ie (see what appliances etc maybe drawing the most power ). I also have a account with my energy dashboard so I can monitor my peak/off peak usage and times. My usage when no one is home is around .5KW and even in winter one sunny day has charged the battery (14.9kw) to 96% capacity. We usually get home around 7pm so its dark this time of year. Any power we use during now and daybreak is drawn from the battery and the grid only is used when the battery is exhausted. Say in summer once the solar has charged the battery any extra solar generated will feed into the grid.
With current solar tariffs and the possibility of those feed in tariffs decreasing in the future batteries are the way to go. I foresee the price dropping also and the capacity only increasing.
 

Hysteresis and harmonics causing torsional oscillations are not good for shafts, cap banks, trannies, skin effect, etc
 
SirRumpole said:
I agree, but I doubt that a totally free market without any government intervention is the way to go either.

It's too easy to jack up prices for an essential service.
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I think it was a mistake privatizing the energy industry. Some things should be in the governments ha
Can I ask what the price of the system was?
Did the house need much rewiring done?
 

Thanks for the info Matt, it would be good if you could give us an update occasionally.
 
In simple layman's terms the issue from an overall grid perspective is that of not having control over the means of generation whilst still needing to precisely match generation with load at all times.

Keeping all this deliberately in very layman's terms, if the load is 1000 MW (to keep it simple) and it's all conventional generation (coal, hydro etc) then that's dead easy. Adjust the output of one or more generators as load moves up and down.

If 100 MW of that load is being supplied by lots of little solar systems then it's not hard to balance that with the other 900 MW that is supplied from centralised power stations. Slightly harder but not hard as such.

If however 500 MW is from small solar then now it's getting somewhat harder to balance the rest. Any load change is in % terms now twice as large an impact on the power stations plus they've also got to deal with changing output from the solar systems. What was a slow and fairly predictable change in output during the course of the day is now an erratic and at times rather fast one. If solar output drops at the same time load goes up, or vice versa, then that doesn't make the task of keeping the system stable easy with such sudden and large changes in power station output now being required.

If we take it to say 800 MW from small solar then we run into problems in that he conventional power stations mostly can't ramp down that far, or can only do so with extreme inefficiency. That's one problem, the other is that a 10% change in load is now a 50% chance in power station output, plus we've got 80% of the generation subject to change at any moment if a cloud comes across, and it all looks rather precarious which indeed it is.

If we take solar above the actual load then frequency goes up until something trips. That's just asking for the whole grid to end up dead. Playing "who blinks first?" games with huge machinery on one side, millions of inverters on the other and a few $ billion worth of electrical equipment in the middle isn't something anyone would sensibly do.

What happens in a fault is a key consideration in all of this too. Using Victoria as an example, putting solar on every house is fine but we need to consider what happens to the overall grid if a non-solar fault were to black out the Melbourne CBD or the Alcoa smelter at Portland (as two examples of big loads and not much solar). All of a sudden you've got a lot less load but you've still got the solar systems churning out the power and that's a problem if the scale is large enough.

Overall, yes we can use solar energy but to make it work reliably and economically requires more than just putting up lots of panels and hoping for the best. Just like investing involves more than buying a dozen random stocks and thinking you're going to be rich.

Whilst on a small scale King Island is an example of how all this can be made to work. It is running right now on 100% wind and solar - yes 100%, there's no "conventional" power being generated at all. So it's all doable with the right approach. Live data for King Island is here for those interested: http://www.kingislandrenewableenergy.com.au/

So far as the Victorian government's scheme is concerned, I'm by no means against the idea but I do wish politicians would tell the full story. Doing this now means other things need to be done also. To not mention that bit is a bit like a politician committing to building a nice new railway to wherever and failing to mention that their plan is only for the track and that trains and train stations will also be required in order for the whole thing to work but they're leaving that bit for someone else to work out.
 
aussymatt said:
Im currently running a 5KW system with a tesla power wall 2 battery
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A question if you don't mind - have you done, or are you aware of way do to, any "smart" stuff with the use of this?

My thinking is specifically in regard to Time Of Use (TOU) metering with different prices at different times of the day. Long story short I've had a few people tell me "can't be done" but my thinking is very much "it must be possible".

Any thoughts?
 
Smurf1976 said:
http://www.kingislandrenewableenergy.com.au/
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Very interesting. I notice they have a flywheel storage which I mentioned before.

I assume that if the flywheel (and battery) figures are negative, they are taking power out of the grid and therefore being charged ?

I assume that the resistor is a "dummy" type load where extra power can be dumped instantly in order to maintain frequency ?
 
Yes - negative flow means power into the battery or flywheel and positive flow would be from the battery or flywheel back to the grid.

Resistor is effectively the "brakes" on the system to get rid of surplus power. In simple terms it's a great big heater - surplus electricity goes in and hot air comes out.

It was done at King Island first but the same basic system, albeit more refined, is being used on Flinders Island (Tas), at Coober Pedy (SA) and elsewhere.

So all this stuff is doable, just needs some proper thought.
 
So through Energy dash board I can see when peak usage and rates apply and when off peak does. I try to limit most of my consumption on off peak if possible . My hot water system being a large drawer is set to off peak times but the battery picks up that usage is I have sufficient charge which in summer in NE vic id imagine I would most of the time. like most people i'm out the door 7.30am and not home till 7pm so I get some peak usage before I leave and when I get home between 7pm-11pm . Again the battery picks up this usage is charge is present. If not the grid takes over . This is still in winter and we have had a lot of overcast and wet days here in August. A usual summer here I suspect full charge most of the time.

see attached to compare the 15/8/18 when there was little sun but enough for the solar to run household usage during the day while vacant
16/8/18 when battery was exhausted until solar kicked in around 8am and ran the household and charged the battery to run night time usage and into the 17/8/18 again when battery ran usage all night.
 
A picture of the tesla app that allows you to monitor usage . you can see this was at night time when I got home . we had a sunny winter day and battery was at 90% +. I had the TV, a few lights, fridge, 2 freezers and a fan that exhausts hot air from the inbuilt wood heater going. You can see total power consumption that the battery is providing and the grid (left side ) is not in use . The solar at the top also isent in use due to it been night time .
 
I hope the rebate only applies to solar hot water systems where the tank is remote, there are already dodgy installers putting tanks on roofs without any consideration to the supporting structure. Putting a 500-600kg system is a great way to cause cracking in ceilings as well as other issues.

We had solar hot water with our house to achieve the 5 star rating, this consisted of 2 collector panels on the roof. Come home to water gushing out of the frost valve, made a warranty claim and they replaced the valve, well this happened 2 more times but the 3rd time it was out of warranty. The company told me the hoses were faulty and they could replace them for about $800 by memory. Rang a plumber and got him to disconnect the whole system, he told me you wouldn't believe how many of these they have disconnected for the same issue. Didn't even notice a significant increase in the gas bill after they were disconnected.
 
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