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Solar Panels

knagelli

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I have a different problem , I cannot feed into grid as the community already has many households with Solar Panels installed and the transformer cannot handle any additional load.

So I was planning to have either the Lg/Tesla batteries installed as I intend to avoid gas usage as much as possible.

Did anyone have Tesla Powerwall 2 installed in recent times as battery storage device when you are not feeding to grid.
 
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Yes, it is the transformer plus the solar panels but for different reasons.

The panels in the street has pushed the grid voltage close to the max specification.
The grid electricity managers can sometimes turn the transformer output voltage lower. However this might make the grid voltage too low during the night - it’s a balance.

There are transformers with dynamic voltage output but most are not


Even if you were allowed to export, you will find that your inverter will prevent export as all inverters sold in AU have max export voltage to prevent overvoltage in the grid.

If the voltage required to push electron from panels to grid is higher than max grid voltage, your inverted will cut the export function.
 

exceladdict

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We have a 25kw inverter and a 20 kw array (The other 5kw will be going in soon).

even though the limit is 5kW, they allowed the system as it did not increase the grid voltage too much. The 5kw limit was put in place to manage the inevitable increase in the grid voltage. The further you are away from the transformer the lower your grid voltage.

is yours a 5kw hard limit?
Nice, I'd really like to install up to the number of panels my roof can support/fit.

The hard IEG limit from the distributor (western power) is 5kw for single phase, and 15kw for three-phase. However retailer (synergy) also apply two further rules to be eligible for the FIT: inverter size limit to 5kw, and if you have a battery, it mustn't export to the grid at all.

Back-of-the-envelope calculations suggest that 5kw in Perth generates around $700-$1000 per annum if 100% exported based on 7c/kw FIT, so it's not insignificant to miss out on it completely.
 

JessicaTam

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Nice, I'd really like to install up to the number of panels my roof can support/fit.

The hard IEG limit from the distributor (western power) is 5kw for single phase, and 15kw for three-phase. However retailer (synergy) also apply two further rules to be eligible for the FIT: inverter size limit to 5kw, and if you have a battery, it mustn't export to the grid at all.

Back-of-the-envelope calculations suggest that 5kw in Perth generates around $700-$1000 per annum if 100% exported based on 7c/kw FIT, so it's not insignificant to miss out on it completely.
That's interesting. We have a 6.5kw system limit for exporting to the grid. But if I install a battery I can go above that.
 
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RAM

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Has anyone had experience with a company called "National Grid Support Service"? May also trade as "Safer Solar".

Also, has anyone used HT 345W panels?

I've received a quote from them and the rep had much better knowledge than all the others I've received quotes from.

Thanks in advance.
These days no matter what contractor/company you are looking at the first step is to do a specific search on the company name (within " ") folowwed by several different terms such as - troubles, problems, issues, fines. Ten minutes work can save much money & heartache.

So "National Grid Support Service" problems - yielded a good list, such as this one (pretty reputable site) which lists many different installers:

National Grid Support Service Reviews | 48,761 Solar Installer ...
www.solarquotes.com.au › Solar Panel Installers


Rating: 4.4 - ‎4 votes
National Grid Support Service is a Solar Power Installation company based in Launceton and serves TAS. Here are their reviews as submitted by visitors to ...

Now there are a number of 'chameleon' companies that copy a good company's name & use it in a different state for example. So I hope you're based in Tasmania?

The Solarquotes site has been around a few years & I have found it to be a great 'primer' to refer people to so they can learn what they don't know (& isn't mentioned) about solar panels, batteries etc.

For example: Most think that if you install 10 x 300 watt panels then on a good day with the sun just right - you'll produce 10 x 300 = 3kW of power.

WRONG.

Other than perhaps on the very first 2 to 4 days if in the 3rd week of August through to early September - you just might see it hit 3kW briefly once or twice. After a week you'll be lucky to see 2.7kW.

Why? Solar panels degrade massively when first installed, so a panel sold as 300 W may actually be able to generate at 330 W on day 1 (depending on the brand) but starts degrading as soon as sunlight hits it. This initial decline is known, allowed for & calculated.

However, while it may (if you're lucky) generate 300 W at the best time of day at the panel, it then gets transmitted along the wire (transmission losses kick in) and reach the inverter (major losses here) before coming out again as AC. The heat given off by inverters is electrical energy lost in conversion as heat energy.

The Solarquotes site has a very detailed explanantion about these losses.

Personally I believe if you're sold an installation as 5 kW then that is what it should be producing at the point where the electricity becomes available to the house - not on the panel before going into the wire.

So paying a small amount extra to get a double diameter wire can lead to electricity production increasing over the life by 1 to 3% depending how long a run the wire has. For our house, the extra cost was.......

$22.70.

Amazing how cost reduction gets through to such a stupid degree everywhere vs the benefit to the consumer foregone.

Similarly, choosing an inverter that provides the optimum conversion rate (least heat etc) for the typical temperature range where you live can (from a German report I found) make a 3- 12% difference. Some inverter brands only work efficiently when close to their max output, others work efficiently over say a 70% range. Since you only produce close to max on maybe 80 days a year and then for maybe 2 hours a day (at best) - then the expensive inverter with highest efficiency (at max) is not the one to choose.

Positioning the inverter out of direct sunlight & in a drafty place = more power output. Moving an inverter a few cm to be totally out of the sun can increase performance by several % (more depending on the brand etc).

Some installers are really switched one (bad pun I know) and understand this. Many do not.

Batteries

Unless a new build facing a huge connection cost then in most cases any type of battery will not make sense unless you suffer frequent blackouts.

WHY? The maths of the financial cost/benefits don't stack up (yet). The great hope is they will soon. Especially as the equivalent cost in getting the capacity via an EV battery is around 1/4 or less of a home storage battery. Annoying that.

For many, especially in warmer areas then a heat pump hot water system has a much better payoff - HOWEVER just like with international airfares out of Australia - there is an Australian premium in the price. Otherwise this would be an absolute no brainer in every case.

Eg: In Hawaii a large capacity heat pump HW costs around $1,000. Made by the same manufacturer the same size traditional electric model costs $600. With Hawaii having Australian style power prices - the cost savings of the heat pump pay off the extra cost in around 16 months for the typical 3 to 4 person household. The $1,000 cost is net of a Hawaii rebate of $250 paid by the State Govt to offset the load diminishing benefits.

In Australia the cost differential is many times greater but still worth doing the numbers on as for most it comes out ahead by a good distance. Even more so if you will no longer use gas HW and can disconnect from gas totally.

Some statistics to think over:

From our modest PV installation put in Aug 2013 (yes I saw higher generation for about 2 minutes at 11.30am on day 1 - 101.8% of panels installed).

So nearly 7 years in operation @ "Impossible efficiency" = quote from panel manufacturer

Net use of power from grid = 65 kWhs (avg a little over 9 kWhs a year - how's that for guestimating what we needed?)
power from grid = 14,954
power to grid = 14,889

PV kWh generated = 20,819
PV hours operating = 26,705

So, despite best efforts the max we've been able to self consume is around 20%. Setting timer to do washing in middle of the day, dish washer, etc - most goes to the grid.

What is illuminating (to some) is that per kW installed the avg generation per hour when operating is just 390 watts.

Now this takes into solid cloud cover days (East Coast Lows = THE ENEMY), oddly enough the panels have produced more watts during massive downpours than on days with an East Coast low & no rain. Recently on a fine, 15 to 18 degree day, with ECL it produced a total of 320 watts over 7 hours (avg 23 watts per kW installed per hour). The torrential rain day generated 3.08kWhs.

.......

The more research you do the better - it can help stop you getting too obsessive ;)
 

exceladdict

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State MP not only replied to my email but called to discuss on Friday, so here's hoping Synergy at least consider the issue without brushing it off.
 

cove

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Exceladdict we have 3 phase in a PERTH suburb and have an 18 kWH system so no feed in at all. Our electricity use has increased as we have been heating our home this winter rather than using the pool heat pump. We are doing that so grandma is kept warm. We should have our lift installed shortly so our power use may go up a bit. I am thinking a battery might now have a 5 year payback so I will contact the system installer to see if my calculations are correct.
 

RAM

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Exceladdict we have 3 phase in a PERTH suburb and have an 18 kWH system so no feed in at all. Our electricity use has increased as we have been heating our home this winter rather than using the pool heat pump. We are doing that so grandma is kept warm. We should have our lift installed shortly so our power use may go up a bit. I am thinking a battery might now have a 5 year payback so I will contact the system installer to see if my calculations are correct.
Unless getting a massive State Govt subsidy (SA for example) then very UNLIKELY you'd have a 5 yr payback.

Much of the material put around shows the payback for installing solar panels AND a battery at the same time.

Solar panel payback, in some very lucky cases, can be as low as 3-4 years. Generally less than 6 years for a quality system these days.

A battery, in most case has a longer pay back period than its expected life unfortunately. Think how mobile phone batteries degrade = Li Ion, same as most batteries. Other chemistries (flow batteries) also are not financially viable for 99.99% of residential cases, and only in quite a limited number of commercial cases (perhaps 3-5% if that).


Fun (sad) fact.

There was a study done over a 5 year period (think it was mid 2000s to end 2000s) which tracked household power consumption for the year prior to installation (actually 4 full quarterly power bills prior) and 4 complete quarterly bills after. Included what was fed into grid etc.

Outcome: median household increased power use (not counting unmonitored self-generation use) increased.

So some follow-up interviews were done. Bulk of increase came in either coldest winter periods or hottest summer periods. Explanation was that people felt that as they were 'doing the right thing' that using their heating/cooling more was not a problem.

Yes, their overall power bills were still lower due to receiving feed-in-tariff but if you could add in the self-generated & self-consumed electricity (as peoples' fridges, freezers, clocks on microwaves, stoves etc etc use power for even the most 'power saving' households - electricity use from all sources increased over 25% it was estimated.

Battery Payback

Have a DETAILED look through Solarquotes.com.au (I think it is but did mention it in slightly earlier post). I think they have a very good calculator to see if a battery makes financial sense. Covers every state (taking into account power prices etc).

When I checked their calculator against mine I did find a couple of incorrect assumptions that actually make a battery look better than it is. They said they'd adjust it to fix the calcs.

You can do a pretty reasonable rough (close enough) figuring with a piece of paper & simple calculator - no need to get super accurate & build-in time value of money.

Typically a battery only comes with a 10 yr (max for most brands) warranty/guaranty. That does not mean 100% output/storage for 10 years either, but a declining trend just like a mobile phone battery (also Li ion...).

# The amount of energy you put into a battery is MUCH more than the battery gives you back

The extreme case are the mega-batteries aka Pumped Hydro. The existing pumped hydro schemes such as the 1950s Snowy require 1.5x the energy to pump the water up as it then produces letting it run back down hill. So approx a 67% efficiency ( 1 / 1.5).

Li Ion efficency is normally between 83 to maybe 90%. So if 83% requires 120 kWh used to get 100 kWh out later. Now ambient air temperature has an impact, as does the wiring used to connect the battery, brand & type of battery, how located (in a breeze or not) etc etc.

# You no longer get the feed-in-tariff for the power used for the battery

Now, FITs are being reduced each year but they still have some value. For more than 3 years out then I assumed they're only worth 3 cents/kWh as I see bad times ahead for all generators whether renewable energy or fossil. Just like anything there are booms & busts IMHO (but that's another 2,000 word post).

But if you're like many households then between 80% to 60% of your power goes to the grid. So the FIT can be a nice amount. Every so often a retailer seeks to increase market share and offers a great FIT. For example in 2019 Origin had an offer, not too publicised but designed for serious 'offer' seekers, had a FIT of 21 c/kWh for some states & 16 cents for others.

Whatever is used for the battery no longer earns the FIT, and due to the efficiency loss, the cost for each kWh out of the battery is effectively up to 1.2 x the FIT. So in our case it would be 1.2x 21 cents = 25.2 cents/kWh currently vs paying 29.428 c/kWh from the grid.

Saving = 4.228 cents/kWh. Making a little over 4 cents is an extreme example - but that's what the first year would have been for us.

When I calculated payback with that FIT for yr1, then 10c Yr 2, 5c for Yr 3 and 3c thereafter - the payback period was around 1.9x the expected battery life = BAD FINANCIAL DECISION.

That's before adding in the time-value-of-money (present valuing future cashflows).

There's much spin, smoke & mirrors about batteries. One day they will make sense for most residential households but I suspect it will be via using an electric vehicle's battery if the rumours of Tesla's million mile battery advance prove correct.

For now, adding an extra 1 kW of panels to what you were planning will make you slightly financially better off - especially in WA where (I think) everyone pays the same rate per kWh regardless of whether in Perth or 2,000 km away with powered produced from diesel by the WA Govt.

Installing a battery will only make the installer & manufacturer better off.
 
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exceladdict

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Exceladdict we have 3 phase in a PERTH suburb and have an 18 kWH system so no feed in at all. Our electricity use has increased as we have been heating our home this winter rather than using the pool heat pump. We are doing that so grandma is kept warm. We should have our lift installed shortly so our power use may go up a bit. I am thinking a battery might now have a 5 year payback so I will contact the system installer to see if my calculations are correct.
Out of interest, how much daily generation are you getting these days in Winter?

Unless getting a massive State Govt subsidy (SA for example) then very UNLIKELY you'd have a 5 yr payback.

Much of the material put around shows the payback for installing solar panels AND a battery at the same time.

Solar panel payback, in some very lucky cases, can be as low as 3-4 years. Generally less than 6 years for a quality system these days.

A battery, in most case has a longer pay back period than its expected life unfortunately. Think how mobile phone batteries degrade = Li Ion, same as most batteries. Other chemistries (flow batteries) also are not financially viable for 99.99% of residential cases, and only in quite a limited number of commercial cases (perhaps 3-5% if that).


Fun (sad) fact.

There was a study done over a 5 year period (think it was mid 2000s to end 2000s) which tracked household power consumption for the year prior to installation (actually 4 full quarterly power bills prior) and 4 complete quarterly bills after. Included what was fed into grid etc.

Outcome: median household increased power use (not counting unmonitored self-generation use) increased.

So some follow-up interviews were done. Bulk of increase came in either coldest winter periods or hottest summer periods. Explanation was that people felt that as they were 'doing the right thing' that using their heating/cooling more was not a problem.

Yes, their overall power bills were still lower due to receiving feed-in-tariff but if you could add in the self-generated & self-consumed electricity (as peoples' fridges, freezers, clocks on microwaves, stoves etc etc use power for even the most 'power saving' households - electricity use from all sources increased over 25% it was estimated.

Battery Payback

Have a DETAILED look through Solarquotes.com.au (I think it is but did mention it in slightly earlier post). I think they have a very good calculator to see if a battery makes financial sense. Covers every state (taking into account power prices etc).

When I checked their calculator against mine I did find a couple of incorrect assumptions that actually make a battery look better than it is. They said they'd adjust it to fix the calcs.

You can do a pretty reasonable rough (close enough) figuring with a piece of paper & simple calculator - no need to get super accurate & build-in time value of money.

Typically a battery only comes with a 10 yr (max for most brands) warranty/guaranty. That does not mean 100% output/storage for 10 years either, but a declining trend just like a mobile phone battery (also Li ion...).

# The amount of energy you put into a battery is MUCH more than the battery gives you back

The extreme case are the mega-batteries aka Pumped Hydro. The existing pumped hydro schemes such as the 1950s Snowy require 1.5x the energy to pump the water up as it then produces letting it run back down hill. So approx a 67% efficiency ( 1 / 1.5).

Li Ion efficency is normally between 83 to maybe 90%. So if 83% requires 120 kWh used to get 100 kWh out later. Now ambient air temperature has an impact, as does the wiring used to connect the battery, brand & type of battery, how located (in a breeze or not) etc etc.

# You no longer get the feed-in-tariff for the power used for the battery

Now, FITs are being reduced each year but they still have some value. For more than 3 years out then I assumed they're only worth 3 cents/kWh as I see bad times ahead for all generators whether renewable energy or fossil. Just like anything there are booms & busts IMHO (but that's another 2,000 word post).

But if you're like many households then between 80% to 60% of your power goes to the grid. So the FIT can be a nice amount. Every so often a retailer seeks to increase market share and offers a great FIT. For example in 2019 Origin had an offer, not too publicised but designed for serious 'offer' seekers, had a FIT of 21 c/kWh for some states & 16 cents for others.

Whatever is used for the battery no longer earns the FIT, and due to the efficiency loss, the cost for each kWh out of the battery is effectively up to 1.2 x the FIT. So in our case it would be 1.2x 21 cents = 25.2 cents/kWh currently vs paying 29.428 c/kWh from the grid.

Saving = 4.228 cents/kWh. Making a little over 4 cents is an extreme example - but that's what the first year would have been for us.

When I calculated payback with that FIT for yr1, then 10c Yr 2, 5c for Yr 3 and 3c thereafter - the payback period was around 1.9x the expected battery life = BAD FINANCIAL DECISION.

That's before adding in the time-value-of-money (present valuing future cashflows).

There's much spin, smoke & mirrors about batteries. One day they will make sense for most residential households but I suspect it will be via using an electric vehicle's battery if the rumours of Tesla's million mile battery advance prove correct.

For now, adding an extra 1 kW of panels to what you were planning will make you slightly financially better off - especially in WA where (I think) everyone pays the same rate per kWh regardless of whether in Perth or 2,000 km away with powered produced from diesel by the WA Govt.

Installing a battery will only make the installer & manufacturer better off.
Thanks, I've found solarquotes extremely helpful. The TL;DR seems to be the only good reason to get a battery is if you want to feel good/brag about it. I'll need to install a smart meter to monitor our actual usage in our new place (currently around 8-11 units a day, more lately due to working from home) but our payback on a battery on current numbers is somewhere around double the warranty period (15-20 years).
 

RAM

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Thanks, I've found solarquotes extremely helpful. The TL;DR seems to be the only good reason to get a battery is if you want to feel good/brag about it. I'll need to install a smart meter to monitor our actual usage in our new place (currently around 8-11 units a day, more lately due to working from home) but our payback on a battery on current numbers is somewhere around double the warranty period (15-20 years).
You can achieve almost as much without installing a smart meter - simply go & read you meter first thing in the morning (ideally close to the same time each day) and then at least once in the evening. If you're home during the day (weekends etc) then adding additional readings is useful.

WARNING - Installing PV can be bad for other's sanity as many PVers generate OCD traits....

Also for the more OCD of us - you can buy a plug-in power meter (typically $10-$20) which you can move around to see exaxctly how much your fridge uses over a period, or how much that load of washing uses. Most unexpected was the cost of boiling an electric kettle - amazing the difference when you accurately boil enough for what you want vs just filling it up without thinking each time. One week on - the power consumed dropped by 60% once even our children realised how much it used.

They loved seeing how the current watts (not intentional pun) changed, one aspect I noticed was how the grid voltage fluctuated massively - even from second to second. Bought some extra surge protectors shortly afterwards.

For example - the amount of power most dishwashers (that heat the water themselves) use is NOTHING compared with how much power is used by an oven.

Quite often - if you install PV then the power company/grid company may pay for the cost of the smart meter - otherwise you get to enjoy watching your power meter spinning backwards. Rules could have changed since we installed PV but never assume....

This is perhaps one of the rare times in your life that you want your service company (PV installer) to be slow in submitting the completed installation paper work. We got the joy of seeing our power meter spinning backwards (during daylight) for just under 2 weeks! So effectively our 'unofficial' FIT was the same as the price of power from the grid. Seems (with initial super generation from panels) that the reading when they installed the smart meter was nearly 150 kWh below what it read when our PV started generating (ie: we sent close to 150 kWhs to the grid than we drew from it).

Yes, ok, I was tracking the readings...

It was a sad day when AusGrid turned up to install a smart meter at no (official) cost to us - only the lost 100% FIT....
 

Hvr

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Here in Melbourne I can see how much I've used and fed in on 30 minute intervals.
If you're in a Powercor/Citipower area then log in here and you can check your usage.


And yes i have a spreadsheet with daily generation, usage, feed in, and it calculates the daily cost.

We got smart meters for free here many years ago.
 

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