Solar install. Can smart meters be configured for this?

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Jaxson

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#196274 25-May-2016 12:19

Hi,

Am considering Solar PV for home, and have read that this often requires the meter to be changed for a 2 way capable unit, so you can be supplied electricity at commercial rates, but supply your solar generated electricity back at the much lower wholesale rates.

My question is, give we were upgraded to a 'smart' meter a few years back, can this same meter be configured for use with home generation, or would I need to purchase/have installed a new 2 way meter?

With the increase in solar generation predicted, it just seems an expensive waste of money to have rolled out smart meters that can't be used/configured for this purpose in future.

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#1559324 25-May-2016 12:20

I am pretty sure it requires a new input/output meter - when I got my solar installed they had to replace the meter and this was on a recent new build so the meter was only a couple of years old. It was all paid for my my lines provider however so no cost to me.

timmmay

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#1559326 25-May-2016 12:23

I wonder if there's an option not to export back to the grid? It hardly seems worthwhile for 5c/kwh or whatever they pay. However there's no point them paying much more because the national floating power rate is way way below what they charge, anywhere from 3c/kwh to 15c/kwh usually, occasionally higher. Use all the power you can as it's generated, or look into storage - which may be too expensive still.

richms

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#1559329 25-May-2016 12:32

Mine had to be swapped out and the new meter hardware looks identical to the old one. I also have lost the smart part of it and someone turns up occasionally to look at the numbers on it.

Then genesis energy send me a buyer created invoice for the 60c of power I exported by snail mail. Which looks like the sort of thing someone would prepare in microsoft excel not a real invoice.

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Jaxson

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#1559333 25-May-2016 12:35

SumnerBoy:

I am pretty sure it requires a new input/output meter - when I got my solar installed they had to replace the meter and this was on a recent new build so the meter was only a couple of years old. It was all paid for my my lines provider however so no cost to me.

Nice to know it was covered, but yeah, that seems an epic waste of money to spec smart meters that can't be used in a 2 way mode. Yes it removed the need for physical meter reads, but still, seems a waste.

timmmay:

I wonder if there's an option not to export back to the grid?

Or to simply not bother being paid for anything you do export out?

I'd be planning something very modest to get my feet wet, but maybe a goal of paying for your lines charge each day would be a nice target.

timmmay

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#1559336 25-May-2016 12:41

My thinking for your situation is given that storage is too expensive, you want to align your solar production with peak usage. For me that would be late afternoon when we run heaters in winter and air conditioners in summer, and outside that time it could heat hot water.

Until storage becomes much cheaper I don't think solar is that practical for most people in cities that have a reliable power supply. That Tesla Powerwall is a red herring, too little capacity, too little current it can supply. I'm thinking banks of 300AH cells stored somewhere safe, charged during the day and used as needed. Friend of mine spent $10K on a solar setup, he's saving some money but only because he has two hot water cylinders and a spa pool. His actual savings are only slightly less than mine, and all I did was move to Flick Electric and move some load to off peak - water heating, clothes drying, dish washing.

Jaxson

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#1559343 25-May-2016 12:51

timmmay:

My thinking for your situation is given that storage is too expensive, you want to align your solar production with peak usage.

Oh that's totally what I'm considering, direct online Solar PV, to be consumed as I produce it.

Scheduling of various devices could make use of it, such as delaying start on the dishwasher and washing machine etc.

Starting small as simple things, such as time controlling panel heaters over winter etc.

No batteries initially, if at all. I'm still grid connected, so have no immediate desire to up the capital costs and maintenance associated with storage.

SumnerBoy

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#1559348 25-May-2016 12:58

Check out http://mk2pvrouter.co.uk/. I am using a customised version of one of these, which diverts any excess PV to my HWC cylinder during the day.

Here is a snapshot of my monitoring for the system, showing PV generation, household usage, and HWC usage.

https://snapshot.raintank.io/dashboard/snapshot/CMsRHvUD5ldMZA2HjWkTApYEFn0BEJ6u

You can see that household usage exactly tracks the PV with the HWC making up the difference to my base load.

Using this I don't export anything (unless my HWC gets too hot to take any more).

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timmmay

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#1559350 25-May-2016 13:04

Q1. What is your up front cost for solar inc install?

Q2. What is your realistic cost savings over the course of a typical year? Not the ideal, the likely actual.

Q3. Over say ten years, what is your projected savings, taking into account the up front costs? I know assessing over 10 years isn't the full life of the panels, but if you can't save money in 10 years it sounds like a loser to me. Take into account up front cost and interest you could've earned on that money, maintenance, maybe a 5% per year power price increase.

I achieved 25% power price savings by moving to Flick and using market rate power, with a few minor behavior adjustments and $250 spent on a timer for hot water. I reckon I can get that up to 35% or more with the hot water timer just installed. If you can't save at least 35% over ten years I could call solar pointless.

SumnerBoy

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#1559355 25-May-2016 13:17

When I installed this the buy back rates were much higher and my payback time was around 10yrs. I did a lot of analysis and everything was going great. Then they dropped the buyback rates by over half and now my payback period is closer to 18yrs. So I completely agree, it doesn't make the best financial sense, but it has brought me hours of fun tinkering with it all!

The initial install cost for 3kW of panels was around $11K from memory. With the initial buy back rates, using my typical usage patterns, I was going to be saving a little over $1K per year. So assuming a 25yr lifetime for the panels, I was going to be better off by $15K over the lifetime of the panels. That has obviously all changed. But I have adjusted my system to ensure I use as much as possible now, hence the PV diverter. Previously I was trying to export as much as possible and like you was shifting load to night rates (since I was only paying 10c/kWh at night, but getting 25c/kWh for generation).

Anyway, been a lot of fun and I have learnt a load. So I certainly don't regret it, but I totally understand and agree with your argument. From a purely financial point of view it no longer really stacks up.

I tell you what though, it is still nice receiving $15 power bills in the middle of summer!

timmmay

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#1559360 25-May-2016 13:25

So, $11K up front costs, $1K saving per year, over the course of 10 years that means it costs you $2000 extra in power to have solar panels. Through efficiency and a different power company you could save 25% over the same time, which could be around $7500 savings. Over 20 years you save $9K, but you could save $15K with market rate power and efficiency efforts. Power price rises could completely change this equation.

Seems pretty clear there's no financial case for solar. Benefits for emergency use (if set up right - my friends isn't, his powers hot water only), maybe some other intangibles.

SumnerBoy

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#1559375 25-May-2016 13:49

timmmay:

So, $11K up front costs, $1K saving per year, over the course of 10 years that means it costs you $2000 extra in power to have solar panels.

Not sure how you get to that figure. Previously my power bills came to about $1800/yr (from memory). After solar I calculated these would drop to around $750/yr, based on the higher buyback rates of 25c/kWh. So 10yr cost would be $11K + ($750 * 10) = $18,500. Without solar it would be $1800 * 10 = $18,000. So after 10yrs I would effectively have paid off the solar install, and for each future year I would be $1K better off.

Before I even looked at solar I went through the process of becoming as efficient as possible. I am on day/night rates and moved all space heating (hydronic underfloor heatpump) and HWC boosting to night time. I ensured that the dishwasher was only run after 9pm.

I also did a detailed analysis of the different power companies, comparing their import and export rates against my historical usage, in order to get the best rates.

So I can assure you there was not 25% of savings to be made in my case. I was running as lean and as cheaply as I could be.

timmmay

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#1559381 25-May-2016 14:12

Wasn't talking specifically about you, more the general case, and I'm assuming buyback is essentially nil with the new rates. I was working on the basis of $1K saved per year, which should take into account any buyback. I guess the number I really want is what did you pay for power 12 months l leading up to putting in solar vs what you paid in the 12 months following.

SumnerBoy

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#1559384 25-May-2016 14:21

For the year immediately prior: $1800

For the year after solar install: $750

The reason for the reduction is two-fold, 1) most of our base load during the day (at the expensive day rates) was being provided by solar so no need to import, and 2) on sunny days we were exporting and getting a credit of 25c/kWh. Some days in summer I was making $2-3 credit per day. I think my lowest power bill was about $12 for a month, which included all line charges etc.

Then the buyback rates dropped, and we welcomed a daughter to the world - so our usage patterns have shifted significantly!

timmmay

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#1559388 25-May-2016 14:29

What would your "year after solar" spend been if the buyback rates were what they are now?

SumnerBoy

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#1559389 25-May-2016 14:30

From memory about $1250 - so only a saving of around $550 - which is why my buyback period pushed out to 18yrs-ish.

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