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Small Grid Tie Inverters in NZ?

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Small Grid Tie Inverters in NZ?

Posted 18 Feb '12 10:03 PM

I have a question for anyone out there, NZ based preferably, regarding small grid tie inverters.

I'm not referring to to the big KW inverters that cost 10k+ nor the individual panel based inverters but instead, these ones...

It's an inverter that plugs into an AC wall socket and feeds any power you generate back into your home and even, if you generate enough, back to the grid. No battery banks, no charge controllers, just this small grid tie inverter and whatever you can afford in solar panels.

Can anyone tell me if these are OK to use in NZ? All the reference material I can find is UK or USA based. They seem safe enough, they match the grid supply and cut off during power outages.

I see no reason why they shouldn't be used in NZ, I think they are a fantastic idea for the hobbyist or small scale solar enthusiast to do something green toward there own power bill without the usually prohibitive cost of renewables.

Am I missing some law that says they can't be used or does anyone know of any other reason why they can't be used here in NZ?

Any help, advice and information is appreciated...

Re: Small Grid Tie Inverters in NZ?

Posted 18 Feb '12 10:39 PM

There was a thread recently on a similar subject( a US enquiry) that may help.

I believe most NZ lines companies require the AS4777 standard so approval might be a bit long winded and expensive.

Assuming this plugs into a standard power socket there are a few safety concerns such as getting a shock off the cord pins and the potential to overload a circuit.

I could see some kind of standard specialized socket/circuit for home generation installations to become available though the concern might be that people could plug in equipment without advising the lines company.

Re: Small Grid Tie Inverters in NZ?

Posted 19 Feb '12 12:15 AM

Thanks for the reply.

One of the devices I've seen on eBay is from an Australian stockest... so I'm wondering if it's already AS4777 approved. I'm going to drop them an email to ask out of interest though.

I'm not sure what you mean when you say 'shocked off the cord pins'. The devices look like they turn off 100% if they do not detect a grid voltage. Hopefully the risk of shock is very low but I can't pretend it's not something I'm a little worried about as it does plug directly into the mains.

As for overload, I'm guessing a home trip works both ways but perhaps plugging it in via an RCD plug would make it extra precautionarily safe but the device does appear fused and reverse current protected.

Other than the power supply company, who I'm sure would not be keep to support someone looking to make their own electricity, I'm not sure who to ask for guidance over these devices.

I would like to avoid making a battery based system but I would like to do it without playing with the risks that accompany mains electricity.

Re: Small Grid Tie Inverters in NZ?

Posted 19 Feb '12 12:34 AM

Yes , the inverter only working when it detects mains should be a protection, as long as it can satisfy electrical codes I guess.

Overloading might occur if someone plugged in multiple units but, again, not likely at the wattage described.

NZ power companies support solar, the best is Meridian which is around 30c /kwh.

I do like this idea. Can't see why solar can't become very plug and play in the near future.

Re: Small Grid Tie Inverters in NZ?

Posted 19 Feb '12 12:47 AM

You don't have to ask your power supply company (the company that bills you), but you should have a talk to your lines company - these are the companies the linesmen work for.

The link you posted gave no indication whatsoever that it is AS4777 certified. They also do not allow pickups - just because they hold stock in Aus doesn't actually mean the stock is legal for connection in either Aus or NZ.

Re: Small Grid Tie Inverters in NZ?

Posted 19 Feb '12 04:34 AM

Does anyone know if small grid tie inverters, under 1KW that are AS4777 approved, exist on the NZ market?

Re: Small Grid Tie Inverters in NZ?

Posted 19 Feb '12 08:50 PM

A couple of things that came to could likely install one of these without needing building consent, probably not on roof and little affect to neighbours.

I recall reading that you can't(legally) just connect to an old meter and run it backwards in NZ like the UK guy in the video did. Can't recall reasons but likely invalidates accuracy of meter etc so a new meter would be required.

As Solar Beginner alluded to, it's a great way for people to get started in solar at a low capital outlay. If these systems are approved overseas we are bound to see them here.

Re: Small Grid Tie Inverters in NZ?

Posted 20 Feb '12 06:27 AM


Re: Small Grid Tie Inverters in NZ?

Posted 20 Feb '12 07:56 AM

Very interesting. Suggest you approach your lines company and see what they say.

I've gone from a sceptic to a believer!

Re: Small Grid Tie Inverters in NZ?

Posted 20 Feb '12 08:26 AM

I live in an apartment block in the CDB of WGTN and although my apartment has it's own fuse box and wiring, I'm not sure how the building wiring as a whole would/could react... I guess it shouldn't make a difference as it is independent.

I also have a prepay digital power meter, a Landis + Gyr Cashpower, no idea how that would cope with a small GTI.

Also, how do you find out who your lines company is, I've never heard of the term before?

Re: Small Grid Tie Inverters in NZ?

Posted 20 Feb '12 09:04 AM

Each area is covered by a lines company, looks like you are Wellington Electricity.

Either that or the power company that bills you might help.

Re: Small Grid Tie Inverters in NZ?

Posted 20 Feb '12 09:00 PM

Transpires that digital meters can and often are fitted with 'Significant Reverse Energy (SRE) detection'.

This trips a 'tamper' switch if the meter finds itself feeding back into the grid. This tamper trip can only be reset by the meter company.

Good to know that one's intentions toward green power generation are praised with such flexibility from electrical companies.

Still, if you're fortunate enough to own your own home or rent somewhere with a classic electric meter system, these mini inverters could be a great idea.

Yet again, come on NZ, catch up!

Re: Small Grid Tie Inverters in NZ?

Posted 20 Feb '12 09:58 PM

Solar Beginner. you might want to have a read of PDF link this from the Ecobob home page. Has the info on procedure and rules and regs etc.

As I mentioned you shouldn't contemplate hooking one of these units up without going through the power/lines companies. They would not be happy and with some justification

Re: Small Grid Tie Inverters in NZ?

Posted 21 Feb '12 02:14 AM

A bit off topic but did not know grid tied micro generation is subject to income tax. Anyone had any experience with that particular issue.

Re: Small Grid Tie Inverters in NZ?

Posted 19 Mar '12 05:07 AM

I have been intrested in these units also, there were a couple of units on Trade Me but not any more (just looked) Bring it on I say

Re: Small Grid Tie Inverters in NZ?

Posted 19 Mar '12 06:31 AM

Grid tie,the only way is to do it right with your lines co in full knowledge. As for trade me ,there have been prosecutions recently for trademe suppliers selling sub standard gear. Maybe they have got the message and have withdrawn the suspect gear.

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