Octopus Energy partners with NZ's Classic Homes to build new homes in Auckland with enough solar panels and batteries to guarantee the homeowner won't have to pay a power bill for five years
I agree with this all in principle - and certainly for new homes - but wonder if our energies would better be spent on encouraging building larger scale solar (or wind)? Where a pair of installers might take a couple of days to put 8 panels on a residential roof; the same installers might take the same time to mount 200 panels to a frame in a field outside of town. Of course, resilience-wise it's not exactly the same, and I'm speculating a bit on the numbers, but if exponential growth in renewables is what is needed, and we want the government to contribute to it, a handful of large (publicly owned?) arrays (plus the requisite reworking of our energy buying market) seems like a drastically more efficient way of doing it, compared to 100k+ separate site visits, deliveries, scaffolding erections, electrical compliance checks etc etc,
The Octopus concept sounds great for a standalone home. But are we not supposed to be striving for denser cities, building up rather than out? I see little hope here for homes that are within terraced complexes three to six storeys high (unless walls, as well as roofs, can be used to generate electricity from the sun).
You can have a small solar farm on the roof of an apartment building, add enough batteries and you potentially can cover a lot of electricity. The design needs to take it into account.
Yep, I should be clear, there are two things in play here: 1. the economy and resilience of home solar, and 2. the use of solar to address our collected energy needs. For 1, I actually think the market has this covered, thanks to cheap Chinese panels/batteries. Home solar (for those with a suitable roof) is a perfectly sensible financial decision now, paying for itself in well-under 1/2 the panel lifespans. In fact, the innovation of companies like Octopus Energy is an exemplar of how the private market can deliver this sort of good without the need for any particular government involvement. For 2 - which I think should actually be where the vision of TKP 26/50 is focused - the government does needs to get involved, because our energy market is a giant rort. If - for example - the government provided Aussie-like subsidies for residential solar, it would be far less cost-effective than putting the same money into a) building large scale solar, and b) realigning the energy market structure so folks living in Clyde are not paying Huntly coal-energy prices for their power etc... I should add, there are edge cases, like the Bunnings rooftops, where some 'encouragement' could boost more localised power generation, but I also think regulation forcing energy providers to pay 'market-rate' feed-in tariffs (minus a small administration margin) would immediately make these sorts of mid-scale installations cost-effective for places like Bunnings.
Niwa Solarview thinks otherwise ! Remember, London is further away from the equator than Invercargill, and there is a rapid roll out of solar happening in UK.
Walls, sure. Not as optimal amount of solar energy received, but viable. Netherlands is seeing large amounts of solar fencing being installed in gardens.
It took our installers exactly 3 days to install a hybrid system with 25 panels and they were a team of 2.
If we are serious about increasing solar installation on rooftops we need to invest in more apprentices in this field.
The operative word is invest but this govt seems allergic to it.
Another option is commercial buildings. Every day I look at the roof of Bunnings Warehouse across the bridge from us and think, what a wasted opportunity.
Merav did you pay for it (I see below you switched to Octopus) and if so would you be willing to divulge the cost of this system - I have been ballpark figuring 30K to do this.
Yes, we paid for it. I looked at SolarZero when I started the research and we decided against having to be committed to a provider for so many years.
We are lucky to be able to afford to pay a $30k system (25 panels, inverter & 10.5kw battery) upfront. There are installers that offer a Qcard payment option that gives IIRC 48 months interest free.
Great points regarding the need for apprenticeships & training of installers.
I too feel the same way about my company when I get to work in the morning, it is a long building with a large roof top, could accommodate lots of solar panels.
Question for anyone in the chat...
Does anyone know if extra re-enforcing of roof tops(especially for sprawling commercial buildings like the one I work in) is needed to accommodate solar infrastructure?
Panels typically weight around 20kg. However there is significant wind (uplift) loads that need to be accounted for (around 2400Pa IIRC). Engineering input required.
My suspicion is commercial scale is the sweet spot - big flat roofs with easy access, can put up 100+kW probably as fast as a residential 10kW install. For ours a lot of time was spent running cables through the roof space and at the meter, that would take just as a long for a much bigger install.
Critically for commercial compared to grid - no need for expensive HV inverters, no grid connection delay and no resource consent.
We took a sweat equity approach to keep the costs down.
I've just had our system inspected today (yay !!!). We had 27 panels (11.8kW) with a 3 phase hybrid (HV battery capable, but none fitted currently) 10kW inverter. A tricky install as the roof is curved (hah !) and the house is concrete (bah !).
I did most of the mechanical work including core drilling of concrete and installing required conduit, mounting inverter, mounting rails and panels. The installer did all the stuff I'm not qualified (or don't want to do). I supplied rails and panels, installed/removed scaffold. (Scaffold was $6 per day to hire, but if you get a full package it will be $1k for installation/removal. Be aware of the rules and what height limits there are before you have to use certified scaffolders etc)
Anyway, all up the cost (on a $15k budget) came in at $16k. Alternative quotes came in from $30k down to around $25k with some PC sums which I think were insufficient, so I'm saying we saved $10k. Payback is 5 years.
Performance wise it's as good as it will get with the summer solstice only 2 weeks away, it's currently chucking out 91kWh on a good day and we get export credits of around $14/day.
If you want to take this route you've got to find an installer who is happy for you to do this level of work, you also need more than just average DIY skills. You have to be very clear about where the demarcation points are and the effort required.
But really worthwhile. PM me if you want to know more.
P.S. Because buying a pallet of panels (36) was cheaper, I ended up with 9 left overs. My wife said "trademe", I've ended up acquiring another 5 so will install an additional 5kW on a stand alone garage.
P.P.S. Two installers, one day for their part and 2 hours for their boss to inspect/commission.
Totally understandable concerns. I guess the trick is to do it all with a 'common good' mindset. There's plenty of evidence to show, for example, the shade and condensation provided by solar panels actually support more productive land use in certain industries (sheep farming for example). And, in my opinion, new housing shouldn't be being built on the outskirts of town anyway: We have been spoiled by our miniscule population and large land area, but now it's clear our carbon budgets, economy, and social cohesion require a focus on density and localisation. Regardless, the key is to not allow the narrow lens of individual profit/benefit to guild how we approach these things.
Look, what I would say to is this; it may be an attractive idea to unsorted bottom feeders who think they can get a free ride by avoiding a power bill, but this government has a stake in selling electricity at the highest possible rate and additionally we have an obligation to our sponsoring partners who want to invest in our coal and natural gas assets.
What I would alsos say to you is we have agreements that can't be over ridden for the sake of popular fantasy and we will legislate to prevent such ridiculous ideas becoming entrenched.
Ha! We have switched to Octopus around 2 weeks ago.
After the solar installation I contacted Meridian who was our provider. They fluffed around for a week via back & forth emails trying to figure out if we can get a weekend rate or not and contradicting themselves between the content of the email & the attached file.
So on a the weekend I went online (as you do these days) found a few companies & decided on Octopus.
The rates you get are all showing on their website. I signed up.
On the Monday I was contacted to get the paperwork of solar sorted. A phone call to them got me an interesting information I did not get from Meridian, that if the change of the meter to an import/export can be done remotely it will only cost $22, and then a follow-up email confirming it could be done remotely.
It took a few days for the data to show on the account but it is now my husband's favourite website to see how we manufacture enough power to keep the house going and have enough for a credit to a rainy day.
Meridian lost a customer that will not go back to them until they change their 🦕 practices.
As regards taxation I'm thinking that cos government still owns 51% of three companies they not only have control of how those companies operate but also have an interest in maximising profit and thus their dividends.
You knew that I guess.
But as a new comer to using our roof to generate power I'm still learning.
First, so I sell power to say Mercury they pay me for that. Is this taxable income ?
Second, Because I'm paying much less on my power bill I'm using less of my after tax income. Woohoo.
Finally if I and all other private gentailers are making our power then the profit being made by power companies is less and so the dividend paid to the government is less.
Is this why government is unlikely to promote cheaper solar installations across a substantial number of kiwi houses.
In regard to the taxable income question it is worth stressing that the best possible return to be gained by any homeowner from their solar is by way of consuming as much of your own generation as you possibly can, which includes storing it in batteries or an EV, or as heat in your HWC. This consumption is offsetting electricity that would otherwise need to be purchased so its value to you becomes that which you would otherwise be paying to your supplier (including GST).
The existing supply system in NZ is such that the price any supplier will pay for your generation when exported to the grid is always going to be lower than what you would be paying for it to be supplied. Tax payable, or not, on that exported electricity is not really that relevant.
I have a super insulated house, built in 2019. Have solar panels but no batteries. My latest power bill was $8. This includes charging my electric car during the day. I am home during the day.
My heat pump hot water system increases my homes energy efficiency significantly
I designed my house this way as I knew I would soon be retiring and thought power prices would be going up faster than my income. I have no regrets
I had solar panels put on my North facing part of the roof some years ago now and I can't say they are wonderful. I am not sure but I think it is because of the very very large tree next door. It must block the sun. But my electricity bill is still pretty high. I have changed to gas bottles for heating the water and the house is well insulated so I don't really now why.
I'll start by saying rooftop solar is appealing. I'd like to do it, but I am viewing it as a hard money expense, meaning I'm not going to finance it, and I'm not going to do a deal like SolarZero, which I looked at.
I continue to believe there is no free solar lunch.
Even the Octopus numbers, while intriguing, don't quite add up. A 30K system actually costs 50K if you finance it. In 25 years you will absolutely positively need to do some maintenance, and that will likely include a full battery recycle. At what cost (not considered here). The "no bills" part? Oh, only guaranteed for 5 years. What could go wrong?
To this bean counter, the savings doesn't "dwarf" the costs. But I look at it nonetheless.
There is also the “cost” of using a fossil fuel but it seems the government are hatching a “cunning” plan of reducing these costs by reneging on our international treaties - it would seem reneging on treaties is one of their specialities
Take a look at my comment further up. Being a "reformed" bean counter, I built a spreadsheet with actual consumption and modelled production figures at a 15 minute resolution (yes that is 35k rows). For each row I calculated if it was import or export, and then ran a bunch of electricity companies tariffs through the model to figure out the net return over 5 years. I took the highest and set that as the budget. The system has been in for 2 weeks and is out performing my modelling so looks like cash payback is even less.
A battery made no sense in my model. But each home will be different.
This is amazing! Truly amazing! How to do something excellent to alleviate climate change effects, and how to make homes healthier and improve health outcomes!! What a transformation is available to us!!
We are with Octopus and have solar on the roof, but no batteries. I am impressed with Octopus because 1. During the Energy crisis this winter they offered us a $2 per kWh discount for savings made during peak periods on 5 or 6 occasions. 2. When customers pushed back against price rise/buyback reduction they reinstated the buyback rate to 17c.
The one thing that is not being mentioned in the cost of solar is the cost of inverters. If we add more panels we need a bigger inverter which is a larger expense than the panels.
Our overall generation annually (last year) was higher than consumption, but because we have not got a battery system we needed to buy from the grid as well. Average bill $60.
Something else to consider is that if all of us Kaka community buy solar and batteries (because we can afford to), that leaves those less able to afford power left to pay for maintenance of the grid. How do we lift all boats?
Yes, the equity argument is often overlooked. Just because we own our home and self fund the PV system, does not change the underlying structural issues with how the electricity market as been structured.
Here is a very recent paper from Geoff Bertram giving an account of how we got to where we are now in electricity supply and the changes we need to make to facilitate an electricity supply system suited to distributed power generation such as roof top solar. https://geoffbertram.com/wp-content/uploads/2024/11/viggers-chapter-final-v3.pdf
That is an absolutely brilliant appraisal of the New Zealand electricity market and proposal as to where it needs to be changed and how. The fact that we're rapidly dropping behind Australia's previously coal based generation system should be reason enough and evidence of the reasons for following their lead in adoption of solar dominant distributed generation.
It was done in two stages with the most recent being an upgrade to 9.5kW* of panel feeding an 8.2kW inverter. *The back bank of panels are bifacial so actually gain light from the roof behind them on the back of the panels. The idea of more panel output than inverter capacity results in the inverter reaching peak output earlier in the day and for longer, and increased output on marginal sunshine days.
All up cost of the system is around $30,000 which included some faffing around getting cables under a sealed driveway but we have no batteries. Our intention is to use one of our EVs in a V2G capacity once this technology rolls out in NZ, which should be in about a year's time as the recently revised A/NZ 4777 electrical standard allows V2G to be done here.
Ancillary equipment to our installation are a Paladin HWC diverter which monitors grid export and diverts as much current as possible (~3kW) into heating our water, and an Evnex EV charger which also diverts 'excess' generation to EV charging (7kW). As per my earlier reply, self consumption is key to solar viability and clever devices like these maximise that.
In the last 12 months the system has generated 11,700kWh of electricity which has 'earned' us $3,060 comprising $748 in export and $2,312 in saved import. (As logged by SolarAnalytics). We are Octopus customers and can highly recommend their pricing and customer service. As can be seen we are heading for a <10 year ROI though every rise in retail electricity prices shortens that duration.
This month our Octopus account is tracking toward credit and will probably remain that way until May. On our rural property we charge two EVs and numerous battery garden tools (so no petrol costs), have pumped water supply, 2x 700L chest freezers and the usual home appliances.
A final bouquet must go to our installers. The expertise that these guys have was top notch with more than 12 years experience in the German, Australian and now NZ solar scenes. As the popularity of solar grows it is enticing many wannabes into the sector and it is disappointing to see badly designed and installed systems being foisted on eager customers by poorly skilled operators. The industry needs to be regulated and fully accredited.
Wow Bernard, that was fantastic! I love this solutions-oriented content. It just shows how unimaginative and old-fashioned - and essentially lazy - our power industry is.
Octopus' offer seems a little too good to be true, but that is only because we are so used to the "soaking the customer because we can, while we defer all the maintenance on decades old kit" model of service, we cannot really believe another option is actually possible.
Even if the sums add up slightly differently here, there is so much to be gained potentially from a conversion to renewables: reductions in cost, reduction in carbon budgets, increased network resilience in a land of earthquakes, reduction in dependence on fossil fuels etc. Renewables on a base of hydro generation make this a reasonable target for us to pursue.
Now if only Kainga Ora was actually still building houses...and if only those buildings priced in batteries and solar into the mix...thus bringing this equipment and infrastructure mass into the market and making it the "norm" for all new private houses...and then if only those tenants (who are often those who can least afford it) could be offered very cheap power while in a safe, warm, dry house...
You may have heard Nicola Willis lamenting about Kainga Ora houses costing more to build than "standard" private homes. There are two things that never get mentioned. One is that KO build costs include all the hard landscaping AND they are being built to a higher standard (Home Star 6 or 7). This will definitely make them more efficient and therefore cheaper to run, easier to maintain and considerably better to live in. Residents may not ever want to shift out! This will be no more. Nicola says it is so wasteful!
This government is almost Victorian in its mindset towards those at the bottom. But a particularly narrow, superior and pinched middle-class version of the sentiment (obviously not the big, expansive, Isambard Kingdom Brunel builder side of the ledger).
Rather than admit that there may be any structural element to it, poverty is almost entirely seen as an individual moral defect. You are lazy and feckless, you are weak and make poor choices, so you deserve it. I, however, am industrious and smart, I practiced self-denial and made good choices. So, I deserve my outsized wealth. The state of the world is actually seen as the proof that things are working as they should.
I have written in the comments here before - I think the entire parliament should read A Christmas Carol by Charles Dickens once a year. It's short, not too demanding a read. They might see themselves reflected in its pages and just maybe, like Scrooge's Christmases Past, Present and Future, not like what stares back at them.
We installed Solar a few years ago, thinking that we didn't have enough roof space to instal enough solar. As it turns out, we've been pushing power back into the grid at quite a rate. Today, we installed a battery. So, now we get to save that power and use it instead of pushing it back to the grid, and then having to draw more power later. The banks give interest-free loans to help manage these costs (although they push for you to take it against your mortgage...).
Yes, any and all NZ governments should be finding better ways to roll this out, the faster the better.
Unfortunately, at the moment you need to have the capital/capacity to do this.
I agree with this all in principle - and certainly for new homes - but wonder if our energies would better be spent on encouraging building larger scale solar (or wind)? Where a pair of installers might take a couple of days to put 8 panels on a residential roof; the same installers might take the same time to mount 200 panels to a frame in a field outside of town. Of course, resilience-wise it's not exactly the same, and I'm speculating a bit on the numbers, but if exponential growth in renewables is what is needed, and we want the government to contribute to it, a handful of large (publicly owned?) arrays (plus the requisite reworking of our energy buying market) seems like a drastically more efficient way of doing it, compared to 100k+ separate site visits, deliveries, scaffolding erections, electrical compliance checks etc etc,
The Octopus concept sounds great for a standalone home. But are we not supposed to be striving for denser cities, building up rather than out? I see little hope here for homes that are within terraced complexes three to six storeys high (unless walls, as well as roofs, can be used to generate electricity from the sun).
The accompanying photo looks to show terraced houses?
That’s because this company originated in England!!
You can have a small solar farm on the roof of an apartment building, add enough batteries and you potentially can cover a lot of electricity. The design needs to take it into account.
Yep, I should be clear, there are two things in play here: 1. the economy and resilience of home solar, and 2. the use of solar to address our collected energy needs. For 1, I actually think the market has this covered, thanks to cheap Chinese panels/batteries. Home solar (for those with a suitable roof) is a perfectly sensible financial decision now, paying for itself in well-under 1/2 the panel lifespans. In fact, the innovation of companies like Octopus Energy is an exemplar of how the private market can deliver this sort of good without the need for any particular government involvement. For 2 - which I think should actually be where the vision of TKP 26/50 is focused - the government does needs to get involved, because our energy market is a giant rort. If - for example - the government provided Aussie-like subsidies for residential solar, it would be far less cost-effective than putting the same money into a) building large scale solar, and b) realigning the energy market structure so folks living in Clyde are not paying Huntly coal-energy prices for their power etc... I should add, there are edge cases, like the Bunnings rooftops, where some 'encouragement' could boost more localised power generation, but I also think regulation forcing energy providers to pay 'market-rate' feed-in tariffs (minus a small administration margin) would immediately make these sorts of mid-scale installations cost-effective for places like Bunnings.
Heaven forbid solar panels on the roof at Tiwai
not much sun in a year at Tiwai
Niwa Solarview thinks otherwise ! Remember, London is further away from the equator than Invercargill, and there is a rapid roll out of solar happening in UK.
Ha!
Great points Tim.
Some of the bigger projects built by single developers might work well.
Walls, sure. Not as optimal amount of solar energy received, but viable. Netherlands is seeing large amounts of solar fencing being installed in gardens.
It took our installers exactly 3 days to install a hybrid system with 25 panels and they were a team of 2.
If we are serious about increasing solar installation on rooftops we need to invest in more apprentices in this field.
The operative word is invest but this govt seems allergic to it.
Another option is commercial buildings. Every day I look at the roof of Bunnings Warehouse across the bridge from us and think, what a wasted opportunity.
12 panels plus inverter no scaffolding needed took 4 guys 7 hours. Lunch break was 1/2 hour enjoying pizza from the grateful owners
Names and numbers please. We all need to do this.
Ours was similar to Michal. 10 panels plus inverter, no scaffolding. Team of 3, a day. Solarman, excellent: https://solarman.co.nz/
Merav did you pay for it (I see below you switched to Octopus) and if so would you be willing to divulge the cost of this system - I have been ballpark figuring 30K to do this.
Yes, we paid for it. I looked at SolarZero when I started the research and we decided against having to be committed to a provider for so many years.
We are lucky to be able to afford to pay a $30k system (25 panels, inverter & 10.5kw battery) upfront. There are installers that offer a Qcard payment option that gives IIRC 48 months interest free.
Please pass on your recommendations. That sounds very efficient.
Great points regarding the need for apprenticeships & training of installers.
I too feel the same way about my company when I get to work in the morning, it is a long building with a large roof top, could accommodate lots of solar panels.
Question for anyone in the chat...
Does anyone know if extra re-enforcing of roof tops(especially for sprawling commercial buildings like the one I work in) is needed to accommodate solar infrastructure?
(sorry for the slight tangent)
Panels typically weight around 20kg. However there is significant wind (uplift) loads that need to be accounted for (around 2400Pa IIRC). Engineering input required.
Oh yeah, that's a good point!
Thanks Mate
My suspicion is commercial scale is the sweet spot - big flat roofs with easy access, can put up 100+kW probably as fast as a residential 10kW install. For ours a lot of time was spent running cables through the roof space and at the meter, that would take just as a long for a much bigger install.
Critically for commercial compared to grid - no need for expensive HV inverters, no grid connection delay and no resource consent.
We took a sweat equity approach to keep the costs down.
I've just had our system inspected today (yay !!!). We had 27 panels (11.8kW) with a 3 phase hybrid (HV battery capable, but none fitted currently) 10kW inverter. A tricky install as the roof is curved (hah !) and the house is concrete (bah !).
I did most of the mechanical work including core drilling of concrete and installing required conduit, mounting inverter, mounting rails and panels. The installer did all the stuff I'm not qualified (or don't want to do). I supplied rails and panels, installed/removed scaffold. (Scaffold was $6 per day to hire, but if you get a full package it will be $1k for installation/removal. Be aware of the rules and what height limits there are before you have to use certified scaffolders etc)
Anyway, all up the cost (on a $15k budget) came in at $16k. Alternative quotes came in from $30k down to around $25k with some PC sums which I think were insufficient, so I'm saying we saved $10k. Payback is 5 years.
Performance wise it's as good as it will get with the summer solstice only 2 weeks away, it's currently chucking out 91kWh on a good day and we get export credits of around $14/day.
If you want to take this route you've got to find an installer who is happy for you to do this level of work, you also need more than just average DIY skills. You have to be very clear about where the demarcation points are and the effort required.
But really worthwhile. PM me if you want to know more.
P.S. Because buying a pallet of panels (36) was cheaper, I ended up with 9 left overs. My wife said "trademe", I've ended up acquiring another 5 so will install an additional 5kW on a stand alone garage.
P.P.S. Two installers, one day for their part and 2 hours for their boss to inspect/commission.
You’d be using up land that might be better used for housing, or growing vegetables??
Totally understandable concerns. I guess the trick is to do it all with a 'common good' mindset. There's plenty of evidence to show, for example, the shade and condensation provided by solar panels actually support more productive land use in certain industries (sheep farming for example). And, in my opinion, new housing shouldn't be being built on the outskirts of town anyway: We have been spoiled by our miniscule population and large land area, but now it's clear our carbon budgets, economy, and social cohesion require a focus on density and localisation. Regardless, the key is to not allow the narrow lens of individual profit/benefit to guild how we approach these things.
Look, what I would say to is this; it may be an attractive idea to unsorted bottom feeders who think they can get a free ride by avoiding a power bill, but this government has a stake in selling electricity at the highest possible rate and additionally we have an obligation to our sponsoring partners who want to invest in our coal and natural gas assets.
What I would alsos say to you is we have agreements that can't be over ridden for the sake of popular fantasy and we will legislate to prevent such ridiculous ideas becoming entrenched.
So true, 51% stake in 3 (of 4) power companies!
Thank you, Christopher, for clearing the air.
Ha! We have switched to Octopus around 2 weeks ago.
After the solar installation I contacted Meridian who was our provider. They fluffed around for a week via back & forth emails trying to figure out if we can get a weekend rate or not and contradicting themselves between the content of the email & the attached file.
So on a the weekend I went online (as you do these days) found a few companies & decided on Octopus.
The rates you get are all showing on their website. I signed up.
On the Monday I was contacted to get the paperwork of solar sorted. A phone call to them got me an interesting information I did not get from Meridian, that if the change of the meter to an import/export can be done remotely it will only cost $22, and then a follow-up email confirming it could be done remotely.
It took a few days for the data to show on the account but it is now my husband's favourite website to see how we manufacture enough power to keep the house going and have enough for a credit to a rainy day.
Meridian lost a customer that will not go back to them until they change their 🦕 practices.
This is a fun read. Great points to remember about the import/export meter and the idea of V2G in an electric car to use it as an extra battery.
As regards taxation I'm thinking that cos government still owns 51% of three companies they not only have control of how those companies operate but also have an interest in maximising profit and thus their dividends.
You knew that I guess.
But as a new comer to using our roof to generate power I'm still learning.
First, so I sell power to say Mercury they pay me for that. Is this taxable income ?
Second, Because I'm paying much less on my power bill I'm using less of my after tax income. Woohoo.
Finally if I and all other private gentailers are making our power then the profit being made by power companies is less and so the dividend paid to the government is less.
Is this why government is unlikely to promote cheaper solar installations across a substantial number of kiwi houses.
In a word. Yes.
In regard to the taxable income question it is worth stressing that the best possible return to be gained by any homeowner from their solar is by way of consuming as much of your own generation as you possibly can, which includes storing it in batteries or an EV, or as heat in your HWC. This consumption is offsetting electricity that would otherwise need to be purchased so its value to you becomes that which you would otherwise be paying to your supplier (including GST).
The existing supply system in NZ is such that the price any supplier will pay for your generation when exported to the grid is always going to be lower than what you would be paying for it to be supplied. Tax payable, or not, on that exported electricity is not really that relevant.
I have a super insulated house, built in 2019. Have solar panels but no batteries. My latest power bill was $8. This includes charging my electric car during the day. I am home during the day.
My heat pump hot water system increases my homes energy efficiency significantly
I designed my house this way as I knew I would soon be retiring and thought power prices would be going up faster than my income. I have no regrets
I had solar panels put on my North facing part of the roof some years ago now and I can't say they are wonderful. I am not sure but I think it is because of the very very large tree next door. It must block the sun. But my electricity bill is still pretty high. I have changed to gas bottles for heating the water and the house is well insulated so I don't really now why.
The efficiency and output of current panels is better than it was a few years ago so that could be one thing.
A large tree that blocks the sun is a problem. Maybe talk to the neighbour and see if something can be done?
We have more panels on the south-west facing roof but we did it with good knowledge that it gets a lot of sun even in winter.
I'll start by saying rooftop solar is appealing. I'd like to do it, but I am viewing it as a hard money expense, meaning I'm not going to finance it, and I'm not going to do a deal like SolarZero, which I looked at.
I continue to believe there is no free solar lunch.
Even the Octopus numbers, while intriguing, don't quite add up. A 30K system actually costs 50K if you finance it. In 25 years you will absolutely positively need to do some maintenance, and that will likely include a full battery recycle. At what cost (not considered here). The "no bills" part? Oh, only guaranteed for 5 years. What could go wrong?
To this bean counter, the savings doesn't "dwarf" the costs. But I look at it nonetheless.
There is also the “cost” of using a fossil fuel but it seems the government are hatching a “cunning” plan of reducing these costs by reneging on our international treaties - it would seem reneging on treaties is one of their specialities
$30k? There might be some new prices around. https://tradedepot.co.nz/5kw-smart-hybrid-inverter-with-solar-panel-and-battery/
Take a look at my comment further up. Being a "reformed" bean counter, I built a spreadsheet with actual consumption and modelled production figures at a 15 minute resolution (yes that is 35k rows). For each row I calculated if it was import or export, and then ran a bunch of electricity companies tariffs through the model to figure out the net return over 5 years. I took the highest and set that as the budget. The system has been in for 2 weeks and is out performing my modelling so looks like cash payback is even less.
A battery made no sense in my model. But each home will be different.
This is amazing! Truly amazing! How to do something excellent to alleviate climate change effects, and how to make homes healthier and improve health outcomes!! What a transformation is available to us!!
We are with Octopus and have solar on the roof, but no batteries. I am impressed with Octopus because 1. During the Energy crisis this winter they offered us a $2 per kWh discount for savings made during peak periods on 5 or 6 occasions. 2. When customers pushed back against price rise/buyback reduction they reinstated the buyback rate to 17c.
The one thing that is not being mentioned in the cost of solar is the cost of inverters. If we add more panels we need a bigger inverter which is a larger expense than the panels.
Our overall generation annually (last year) was higher than consumption, but because we have not got a battery system we needed to buy from the grid as well. Average bill $60.
Something else to consider is that if all of us Kaka community buy solar and batteries (because we can afford to), that leaves those less able to afford power left to pay for maintenance of the grid. How do we lift all boats?
Yes, the equity argument is often overlooked. Just because we own our home and self fund the PV system, does not change the underlying structural issues with how the electricity market as been structured.
Here is a very recent paper from Geoff Bertram giving an account of how we got to where we are now in electricity supply and the changes we need to make to facilitate an electricity supply system suited to distributed power generation such as roof top solar. https://geoffbertram.com/wp-content/uploads/2024/11/viggers-chapter-final-v3.pdf
That is an absolutely brilliant appraisal of the New Zealand electricity market and proposal as to where it needs to be changed and how. The fact that we're rapidly dropping behind Australia's previously coal based generation system should be reason enough and evidence of the reasons for following their lead in adoption of solar dominant distributed generation.
This is our solar installation: https://www.solar-one.co.nz/residentialsolar/project-two-ky966-m37fk-39scs-a6l3r-cfbga
It was done in two stages with the most recent being an upgrade to 9.5kW* of panel feeding an 8.2kW inverter. *The back bank of panels are bifacial so actually gain light from the roof behind them on the back of the panels. The idea of more panel output than inverter capacity results in the inverter reaching peak output earlier in the day and for longer, and increased output on marginal sunshine days.
All up cost of the system is around $30,000 which included some faffing around getting cables under a sealed driveway but we have no batteries. Our intention is to use one of our EVs in a V2G capacity once this technology rolls out in NZ, which should be in about a year's time as the recently revised A/NZ 4777 electrical standard allows V2G to be done here.
Ancillary equipment to our installation are a Paladin HWC diverter which monitors grid export and diverts as much current as possible (~3kW) into heating our water, and an Evnex EV charger which also diverts 'excess' generation to EV charging (7kW). As per my earlier reply, self consumption is key to solar viability and clever devices like these maximise that.
In the last 12 months the system has generated 11,700kWh of electricity which has 'earned' us $3,060 comprising $748 in export and $2,312 in saved import. (As logged by SolarAnalytics). We are Octopus customers and can highly recommend their pricing and customer service. As can be seen we are heading for a <10 year ROI though every rise in retail electricity prices shortens that duration.
This month our Octopus account is tracking toward credit and will probably remain that way until May. On our rural property we charge two EVs and numerous battery garden tools (so no petrol costs), have pumped water supply, 2x 700L chest freezers and the usual home appliances.
A final bouquet must go to our installers. The expertise that these guys have was top notch with more than 12 years experience in the German, Australian and now NZ solar scenes. As the popularity of solar grows it is enticing many wannabes into the sector and it is disappointing to see badly designed and installed systems being foisted on eager customers by poorly skilled operators. The industry needs to be regulated and fully accredited.
Wow Bernard, that was fantastic! I love this solutions-oriented content. It just shows how unimaginative and old-fashioned - and essentially lazy - our power industry is.
Octopus' offer seems a little too good to be true, but that is only because we are so used to the "soaking the customer because we can, while we defer all the maintenance on decades old kit" model of service, we cannot really believe another option is actually possible.
Even if the sums add up slightly differently here, there is so much to be gained potentially from a conversion to renewables: reductions in cost, reduction in carbon budgets, increased network resilience in a land of earthquakes, reduction in dependence on fossil fuels etc. Renewables on a base of hydro generation make this a reasonable target for us to pursue.
Now if only Kainga Ora was actually still building houses...and if only those buildings priced in batteries and solar into the mix...thus bringing this equipment and infrastructure mass into the market and making it the "norm" for all new private houses...and then if only those tenants (who are often those who can least afford it) could be offered very cheap power while in a safe, warm, dry house...
You may have heard Nicola Willis lamenting about Kainga Ora houses costing more to build than "standard" private homes. There are two things that never get mentioned. One is that KO build costs include all the hard landscaping AND they are being built to a higher standard (Home Star 6 or 7). This will definitely make them more efficient and therefore cheaper to run, easier to maintain and considerably better to live in. Residents may not ever want to shift out! This will be no more. Nicola says it is so wasteful!
This government is almost Victorian in its mindset towards those at the bottom. But a particularly narrow, superior and pinched middle-class version of the sentiment (obviously not the big, expansive, Isambard Kingdom Brunel builder side of the ledger).
Rather than admit that there may be any structural element to it, poverty is almost entirely seen as an individual moral defect. You are lazy and feckless, you are weak and make poor choices, so you deserve it. I, however, am industrious and smart, I practiced self-denial and made good choices. So, I deserve my outsized wealth. The state of the world is actually seen as the proof that things are working as they should.
I have written in the comments here before - I think the entire parliament should read A Christmas Carol by Charles Dickens once a year. It's short, not too demanding a read. They might see themselves reflected in its pages and just maybe, like Scrooge's Christmases Past, Present and Future, not like what stares back at them.
We installed Solar a few years ago, thinking that we didn't have enough roof space to instal enough solar. As it turns out, we've been pushing power back into the grid at quite a rate. Today, we installed a battery. So, now we get to save that power and use it instead of pushing it back to the grid, and then having to draw more power later. The banks give interest-free loans to help manage these costs (although they push for you to take it against your mortgage...).
Yes, any and all NZ governments should be finding better ways to roll this out, the faster the better.
Unfortunately, at the moment you need to have the capital/capacity to do this.
Once again, it is very expensive to be poor.