Solar scheme gone wrong

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rhills
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Real Name: Rob Hills
Location: Waikiki, WA

Solar scheme gone wrong

Post by rhills »

Thought I'd post to correct some of the well-intentioned, but erroneous information about domestic solar systems. I've had a 5KW system on my home in Waikiki, Western Australia since May 2010. I have tracked the power generated since the beginning via PVOutput, so you can see all the detail there.

I was lucky enough to have my system qualify for the original, WA Govt sponsored NET feed in tarrif so I am paid 48.41 cents for each unit (kWh) that our system feeds back to the grid. Note, this is a NET tarrif so we are paid for the instantaneous difference between what we're consuming and what we generate. If we are producing more than we are consuming, we get 48.41 cents for the NET outgoing power, if we are consuming more than we are producing, we pay 22.62 cents for the NET incoming power.

To clarify with an example, right now, my solar system is generating 4534 watts. At the same time, our house is consuming ~500 watts. This means that our NET result is 4000 watts going out to the grid. If that continues for an hour, I will have exported 4kWh to the grid and will be paid 90.48 cents for that.

Early this morning however, when our system was producing about 1000 watts (about 6:20am today), let's say we were consuming 2000 watts and that situation continued for an hour. Our NET result is 1000 watts coming in from the grid which equates to 1 kWh over an hour, and for which we pay 22.62 cents.

Of course, this generous feed-in tarrif is no longer available in WA, but it is still cost-effective to install a solar system, provided you understand how it works and have it sized correctly. The best strategy for the current rules is to size your system to cover your daytime power usage.

Like most things, it also pays to get your system installed by a good quality company. There are many horror stories about solar installations, of which the situation mentioned by the OP may well be one.

If you're interested in installing solar power on your roof, I recommend you invest some time reading the very long, but mostly very informative Perth Solar Installations Whirlpool Forum thread. Particularly look for posts by "Kaju" who seems to give out very sensible and balanced advice.

Hope this helps someone!
Rob Hills
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Stiive
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Solar scheme gone wrong

Post by Stiive »

Cool logging info - seems its nice and sunny over there Image

If my calcs are correct
From the stats page, you have exported 2,187kWh. @ 48.41c, you've sold $1,058.73 worth of power

Total generation minus sold power is 11,628kWh. @ 22.62c (peak rate?), you've saved $2,630.25

Total benefit of system so far = $3,689
Not bad for 2.5years worth of sun.

Do you mind if I ask how much you paid for the system?


How do you setup that website, do you need anything fancy?


Rgds,
Stiive
rhills
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Solar scheme gone wrong

Post by rhills »

Hi Steve,

Firstly, the export stuff is not accurate at all. I don't presently log my power consumption. I have a "Watts Clever" monitor but presently it monitors net power "flow" but not the direction Image . I had previously put in some export figures when I was manually reading my meter, but I quickly tired of that.

Our power "bill" is averaging about $2500 credit per year. Before our system was installed, power was costing us around $1000 per year, so our system is returning us at least $3500 per year (more if you allow for the increases in electricity prices over the past 18 months.

The downside to being early adopters is that we paid a lot more for our system (about $18K) than you would today. That still gives us a payback period of a touch over 5 years, which we're very happy with.

WRT the logging, anyone can create a (free) account on PVOutput. You can then manually add figures from your system, but if you have an inverter that supports logging, there are a number of programs around that you can use to automatically interrogate the inverter and upload the data to PVOutput. I have a small, low-power linux-based computer that is our backup server and also does our logging via a bluetooth connection with the inverter. It was a bit fiddly to set up but it all just purrs away in the background now. There are also Windows-based programs that will do the logging for you. Which program you choose depends somewhat on what inverter you have.

Cheers,
Rob Hills
AEVA Webmaster
2014 Mitsubishi Outlander Aspire PHEV
Petrol Usage to last refill: Jul 2014 - Oct 2020
Total Petrol: 756.3L
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Av Consumption: 1.12 L/100km
antiscab
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Solar scheme gone wrong

Post by antiscab »

I wonder if anyone with the killer 4kw W 3kw N 4kw E arrays and 5kw inverters are making the dc bus of their inverter common with that of their inverter airconditioner and other dc capable loads (like EV battery chargers)

seems to me it would be possible to *net* 50kwh/day export rather than just gross it.

Matt
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Adverse Effects
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Solar scheme gone wrong

Post by Adverse Effects »

a friend of mine got a 5Kw system installed in the "QLD power sceam" 6 months ago and has just called me asking if they can do what they are doing

he is putting back in to the grid so much that about 1 week full sun days all most covers all the power he uses in the 3 month

he called them when he got the last bill (he was expecting a cheque / money order) they said you now have $<insert number> credit with us on your account

can they not pay him the $ and just say credit on your account

if so they will end up oweing him $10,000's in no time but never have to pay him
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weber
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Solar scheme gone wrong

Post by weber »

Adverse Effects wrote:can they not pay him the $ and just say credit on your account
They have to pay each time he asks them to pay, provided the balance is more than $50. But there is no requirement for them to pay it automatically, say on every electricity bill. You have to contact them after every bill and request payment. Yes, it's a PITA.

Don't ask for a cheque. That can take weeks. Give them your account details for direct payment, if they offer that option. Some retailers may offer automatic payment, now or in the future, but they are not required to.
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).
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Adverse Effects
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Solar scheme gone wrong

Post by Adverse Effects »

thanks

i'll let him know

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Richo
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Solar scheme gone wrong

Post by Richo »

Tell the energy provider there is 19% interest charged on late payments....

So the short answer is NO but the long answer is YES.
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