Electrickery usage with Solar

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    Posted: 26 Nov 2021 at 11:20am
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Earlier in the year there was a thread with chats about solar panels, electricity usage etc.  I had purchased a house with solar panels (no batteries) a year ago tomorrow and a couple of people said they would be interested in overall cost / usage once I had been in the house for a year so ...

I had a quick look at the data available on the Mercury website for me just now.  A summary in round numbers is:

Total bills for 12 months: $1,400 (electricity and gas combined)

Gas usage: $500 (1810 kWh)
Electricity: $900 (2800 kWh)

I haven't dug into the detail to see the seasonal (or monthly) variation but may do that at some stage.

FYI this is for an average 3 bedroom house with 3 people (a lot of "work from home" due to COVID). Gas is for hot water and a gas hob.
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Post Options Post Options   Likes (0) Likes(0)   Quote MATTOO Quote  Post ReplyReply Direct Link To This Post Posted: 26 Nov 2021 at 4:17pm
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Thanks for the update.
Be helpful to compare your year before data though as a comparison.
Just cruising in my now sweetas pimped out Southern 755 HT0!
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Post Options Post Options   Likes (0) Likes(0)   Quote krow Quote  Post ReplyReply Direct Link To This Post Posted: 26 Nov 2021 at 9:28pm
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That's dam good to my mind when ours 5 people is 250+ month Power only and not including the gas hob.
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Post Options Post Options   Likes (2) Likes(2)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 27 Nov 2021 at 9:11am
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We are like you.. gas for hob and water.. put in near 2 yrs ago
You should have an app or computer program that monitors and breaks down all the usage /stats etc.

We put in 14 panels.. they recommended 12, but their break down numbers didnt match up to the 50% of overall production  and 50% usage.
Our bills previously.. before the last increases where around the $300
Consumption ave around the 22/24 kwh per day

Over winter our bill drops about 30/33%, and use most of produced.
Late autumn and early spring around around the 40/45 %
mid spring to mid autumn drops to around 50 to 60%

The amount that goes into the grid over the yr covers the cost of the gas and the bottle rentals.

Install cost was about 14K to add batteries (as at about yr ago) about another14K

I have worked out the most cost effective 'battery' (energy storage) would put large 120 or 180L hot water cylinder in... To redirect any power that would have gone to the grid into the HWC is only a few $100.
That then puts solar heated water into the califont, reducing /not requiring the califont to use as much gas or not even turn on if over 65deg

Down side, means using less gas...but increased cost in gas/ L because the cylinders last longer, same gas volume but the rental factor increases per bottle over time.

 Our original electric bills used to be around the $300/month...now ave under the $150 (even on the resent increase in kwh rates.)
Thats about a 7 yr recovery of capital cost.. at current rates.
 Add another $1500 to 2K to for an outdoor HWC next to the califont...I estimate would remove the big tanks rental and put us back down to a 9kg bottle every few months.

Varies between 2 and 4 adults (son has a flat on the end of the house) and often away for couple weeks at a time. Also run a spa pool, office with computers/ servers etc..3 freezers.
Spa and freezers are on time clocks.. 30 min increments during daylight hrs, alternating between the freezers and spa.
The 30 mins established by starting at 2hr increments, but tened to miss short sunny periods with the spa (draws lot power).. found 30 mins hit more sunny periods  over all longer.. under that the freezers only get a chance to up fully up and run.

Would we do it again? YES definitely

Batteries.. if could afford to do so YES

Batteries to pretty much go off line most of the time...
I.E cover non day light hrs, after a couple winter no sun days... NO
Because of the cost and size of the batteries required, and ideally would put up 2 more panels.

 
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Post Options Post Options   Likes (0) Likes(0)   Quote Bounty Hunter Quote  Post ReplyReply Direct Link To This Post Posted: 28 Nov 2021 at 9:29am
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Originally posted by Phantom Menace Phantom Menace wrote:

Earlier in the year there was a thread with chats about solar panels, electricity usage etc.  I had purchased a house with solar panels (no batteries) a year ago tomorrow and a couple of people said they would be interested in overall cost / usage once I had been in the house for a year so ...

I had a quick look at the data available on the Mercury website for me just now.  A summary in round numbers is:

Total bills for 12 months: $1,400 (electricity and gas combined)

Gas usage: $500 (1810 kWh)
Electricity: $900 (2800 kWh)

I haven't dug into the detail to see the seasonal (or monthly) variation but may do that at some stage.

FYI this is for an average 3 bedroom house with 3 people (a lot of "work from home" due to COVID). Gas is for hot water and a gas hob.

seems pretty cheap for a family hous
do you have simlar figures for what was 'returned to the grid' by the panels?
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Post Options Post Options   Likes (0) Likes(0)   Quote v8-coupe Quote  Post ReplyReply Direct Link To This Post Posted: 28 Nov 2021 at 10:18am
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We looked at solar a few years ago. 
We divided the up front costs of installing the panels by ten years and added it to expected yearly bill according to the specs/sales person.
We would have been effectively paying more for the electricity over the ten years.
Also noting the pittance you were getting back for any you sell back to the grid compared to overseas.
We deliberately did not add in the cost of any finance.
That to would have altered any benefits received and probably pushed the prjected break even point out even further.
Added to this there was/is a possibilitiy one or more of the panels and/or batteries would need replacing during those ten years.
At that stage, the warranty was only five years on the products.
Could be more now.
Max EV battery warranty at the moment is 8 years then your vehicle is effectively worthless except for spare parts or if you decide to purchase and install another bank of batteries later on.
We decided at the current power prices and projected inflation of those prices, it was still cheaper to stay on the grid over those ten years.
Found the old quote and figures, we are still way ahead of the curve now.
I also wanted to wait until A) prices dropped/warranties increased and B) there is an energy efficient and safe way to recycle/manufacture the panels and batteries as those components alone make a mockery of the solar and EV clean image. 
Hopefully Green Hydrogen is being actively considered and on the horizon.
Not trying to hijack the threat, just outlaying the reasons we decided not to go with solar.
At that stage there was just two adults in a two bedroom unit.
Cheers.
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 28 Nov 2021 at 11:23am
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I also thought that before posting.
Since gone to our power company app and the Solar energy app to reference.
We , ave about 3 adults, spa, office with servers, shed with bandsaw, bench saw, lathe, lighting etc regular use a water pump, swimming pool pump, and 3 freezers and spa pool

Power bill $139/ month gross, over the last 2yrs yr, including charges etc..with the power to grid taken off.
$1670/ yr

Previous to solar panels was ave around $310/ per month
$3720 over  1.5 yrs..

keeping min mind there has been several increase in kwh and charges in that time.
 Gas usage including bottle rental around $600/yr

In saying all that..
 Our power usage this month will be around $57 plus charges... maybe loer because the spa pool pump circuit board died a couple weeks back.
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Post Options Post Options   Likes (1) Likes(1)   Quote Ho Dee Quote  Post ReplyReply Direct Link To This Post Posted: 28 Nov 2021 at 11:26am
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Our solar system was commissioned in mid january last year, it runs a four bedroom house with three occupants with the  usual appliances we did run the ducted heating non stop though winter. It  runs a water pump to the paddocks a large shed and the water pump to two houses. Power bill for the 10 months $744.Total power generated 11.6 mw. Looking forward to a whole summer of generation.
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 28 Nov 2021 at 11:43am
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Missed your post V8
 Yes we have been watching the 'market' for many yrs now.
  Yes Results more or less same as you describe...

Also Family moved on , big section in middle Manurewa, gardens landscaping, and spending too much to in looking after rather than fishing and road trips. So knew we will be cashing up to developers and retiring. So once settled in a home we intended to retire in for long time...
Also time to re visit solar.
 Logic being.
Retirement hits the back pocket hard, so reducing over heads on long term..
 Panels last out longer and rather than replace just add a couple to them to take up the efficiency deficit 20 odd yrs down the line.. IF Im still alive at 90 odd.
 Batteries still have a life of around a decade, regardless of use and expensive...And for use to go almost off the grid, means 2 batteries (hence the HWC thing in 1st post .. A work in 'design' progress..)

And along with reducing costs long term, was now the Government going EVs, we dont have the infrastructure to support environmentally friendly electricity supply, either in production and lines...We can see costs going up scary in the near future...

The latter, yes batteries would be nice...
What they dont tell you is you need batteries to still have power if a power cut...the battery is in effect Also the UPS.
 Hence the LPG tanks.. power cut, still got household hot water and cooking.

Anyway thats what we have done, the results , and the whys done , and not done stuff.

What I have not yet looked into is rather than a battery, a small 1.5 to 2 kw generator which is big enough to run the servers, fridges freezers basic lighting over night... plus the odd fresh expresso and cuppa tea.Wink
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Post Options Post Options   Likes (0) Likes(0)   Quote Kevin.S Quote  Post ReplyReply Direct Link To This Post Posted: 28 Nov 2021 at 2:12pm
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I love the idea of solar, and we are in a perfect location for it.  But I just can't make it work financially.  Everything is electric, there are two of us in a smallish 3 bed house but I work from home so I'm here all the time.  Our monthly electric bill averages about $200.  Even if we could halve our bill we'd be lucky to break even on the panel cost over a decade -and we'd be paying out a big chunk of $$ up front.  As we are rural I'd really like to go totally off grid, but the costs to do that are pretty big.

I really like the look of the hydrogen generator battery thing that's being developed in OZ now, maybe in a few years that technology will start to get affordable.  One way or another I think it will get more financially viable in time.
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Post Options Post Options   Likes (0) Likes(0)   Quote Ho Dee Quote  Post ReplyReply Direct Link To This Post Posted: 28 Nov 2021 at 2:48pm
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I figure that at current electricity prices and buy back rates our pay back will be 6.8 years which will hopefully be less as we figure out how to use more power when it is being generated
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Post Options Post Options   Likes (0) Likes(0)   Quote v8-coupe Quote  Post ReplyReply Direct Link To This Post Posted: 28 Nov 2021 at 6:37pm
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Originally posted by Steps Steps wrote:

Missed your post V8
 Yes we have been watching the 'market' for many yrs now.
  Yes Results more or less same as you describe...

Also Family moved on , big section in middle Manurewa, gardens landscaping, and spending too much to in looking after rather than fishing and road trips. So knew we will be cashing up to developers and retiring. So once settled in a home we intended to retire in for long time...
Also time to re visit solar.
 Logic being.
Retirement hits the back pocket hard, so reducing over heads on long term..
 Panels last out longer and rather than replace just add a couple to them to take up the efficiency deficit 20 odd yrs down the line.. IF Im still alive at 90 odd.
 Batteries still have a life of around a decade, regardless of use and expensive...And for use to go almost off the grid, means 2 batteries (hence the HWC thing in 1st post .. A work in 'design' progress..)

And along with reducing costs long term, was now the Government going EVs, we dont have the infrastructure to support environmentally friendly electricity supply, either in production and lines...We can see costs going up scary in the near future...

The latter, yes batteries would be nice...
What they dont tell you is you need batteries to still have power if a power cut...the battery is in effect Also the UPS.
 Hence the LPG tanks.. power cut, still got household hot water and cooking.

Anyway thats what we have done, the results , and the whys done , and not done stuff.

What I have not yet looked into is rather than a battery, a small 1.5 to 2 kw generator which is big enough to run the servers, fridges freezers basic lighting over night... plus the odd fresh expresso and cuppa tea.Wink

Grrrrrr.
Had to sign out then in again, again. 
Had another thought after my post, as mentioned in first posst of the thread, the house was purchased with solar already installed so they are on a winner and cannot lose or wait to break even. Thumbs Up
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Post Options Post Options   Likes (0) Likes(0)   Quote v8-coupe Quote  Post ReplyReply Direct Link To This Post Posted: 28 Nov 2021 at 6:39pm
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Originally posted by Ho Dee Ho Dee wrote:

I figure that at current electricity prices and buy back rates our pay back will be 6.8 years which will hopefully be less as we figure out how to use more power when it is being generated

With or without batteries as well?
If with batteries, prices certainly have come down. Thumbs Up
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Post Options Post Options   Likes (0) Likes(0)   Quote Ho Dee Quote  Post ReplyReply Direct Link To This Post Posted: 28 Nov 2021 at 9:13pm
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thats without batteries v8. Our power bill used to average around $300 a month.The solar system cost 19k. Batteries would be good but they are still expensive.
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Post Options Post Options   Likes (0) Likes(0)   Quote Phantom Menace Quote  Post ReplyReply Direct Link To This Post Posted: 29 Nov 2021 at 8:41am
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Originally posted by MATTOO MATTOO wrote:

Thanks for the update.
Be helpful to compare your year before data though as a comparison.

It wouldn't be a valid comparison - completely different style of house etc. (that's why I haven't included it).
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Post Options Post Options   Likes (0) Likes(0)   Quote Phantom Menace Quote  Post ReplyReply Direct Link To This Post Posted: 29 Nov 2021 at 8:58am
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Originally posted by v8-coupe v8-coupe wrote:


Grrrrrr.
Had to sign out then in again, again. 
Had another thought after my post, as mentioned in first posst of the thread, the house was purchased with solar already installed so they are on a winner and cannot lose or wait to break even. Thumbs Up

Yep, I deliberately didn't factor the solar panels in to my original purchase offer so effectively I don't have to wait for payback. (although they were a good 'extra' that added to the appeal TBH so made the decision to buy easier).

A while ago a Tesla fanboy suggested that it would be a no-brainer to add a battery into the mix.  I did some basic maths:

Powerwall purchase price $14,100 (plus installation)
Assumption: no more gird power consumed therefore $900 per year savings
Payback = 15.66 years (plus installation) 

And that is without looking at whether the capacity of a single Powerwall combined with the existing solar setup is sufficient to cover all house usage all the time. (and also ignoring the base cost to remain connected to the grid)

So ... payback for a single Powerwall is a minimum of 15 years and more likely closer to 20 years ... (given my circumstances)
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 29 Nov 2021 at 4:00pm
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And that is without looking at whether the capacity of a single Powerwall combined with the existing solar setup is sufficient to cover all house usage all the time

 Sort of the issue I mention above.. get a couple cloudy / rainy days and the batteries will not last ....

Friends put in 'off grid solar same time as we did... reason the mid 20 kwh system cheaper than getting power run to the new build.
They still have a back up generator for those occasions, use it 5 or 6 times over winter.
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