Going "off grid" in suburbia

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#2026982 1-Jun-2018 15:49

gchiu:

Electrician just emailed me that we could go to 2 phase, one for each house. But I would need another meter and also new cabling probably from the pole to the house.

From you have said previously, I would grab this with both hands, get a ball park quote and look at getting the ball rolling

- its likely to be well under the 45K you were quoted for solar and will give the second dwelling more than enough capacity ...

gchiu

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#2048459 3-Jul-2018 17:26

The quote is just under $6k for 3 phase power. One phase for each house, and an extra phase to be available when we need it in the future should we install an EV charging port.

Now, I'm told that we need to move from Flick to someone else since Flick doesn't have the agreements in place for us to do all of this changing of the power. And I'll need to find a company that can give me a cheap night rate in case I need to recharge the solar batteries. More research :(

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#2048523 3-Jul-2018 19:42

Surprised that you are not simply connecting 3 phase to both houses. Is that to avoid a switchboard upgrade in the main house?

Especially as quite a lot of EV models support 3 phase charging.

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#2048527 3-Jul-2018 19:51

What EVs support 3 phase? I recall a friend had a hell of a time driving around and charging at industrial places because the stupid clipsal 56 sockets everywhere seems to deploy often have no neutral in them so the adapter cables were worthless.

When I asked about getting 3 phase here, it was $$ heaps, and I was going to have to upgrade all my breakers and stuff because they dont have a large enough big number on them for an upgraded supply, and that meant RCD for them all and much more hassle, so if I do get more supply here I will just be getting a second one to the garage/shed and not touching the house.

Richard rich.ms

RunningMan

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#2048530 3-Jul-2018 19:53

Zoe is 3 phase, and fairly sure i3 is as well.

Aredwood

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#2048567 3-Jul-2018 21:14

RunningMan:
Zoe is 3 phase, and fairly sure i3 is as well.

Add Tesla to the list as well.

Also as batteries get bigger. Trying to charge with single phase will become impractical. Charging a 60KWHr battery from empty will take around 8 hours using 32A single phase. And a 100KW/Hr battery will take over 13 hours. And if you want to use a 15A caravan socket to charge. You will be waiting 16 hours or 26 hours respectively.

With 32A 3 phase. 60KW/Hr takes 2.7 hours. And 100KW/Hr takes 4.5 hours. Much more reasonable charge times.

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#2048670 4-Jul-2018 00:24

gchiu:

The quote is just under $6k for 3 phase power. One phase for each house, and an extra phase to be available when we need it in the future should we install an EV charging port.

Now, I'm told that we need to move from Flick to someone else since Flick doesn't have the agreements in place for us to do all of this changing of the power. And I'll need to find a company that can give me a cheap night rate in case I need to recharge the solar batteries. More research :(

I would go with this option if I was in your position.

While I love off grid setup's, they don't really work financially unless connection costs to the grid are $40k+.

First thing to note is that WEL (I assume you are in WEL's area) doesn't seem to charge extra daily fees for larger capacity or 3 phase connection's (untill you hit 110kVA, you would be 43kVA). This differed from lines companies in other regions that charge more daily fees for more capacity (sometimes heaps more).

This should give you plenty of capacity going forward, and as an added perk, you can run three phase stuff if you like. (big motors, big air-con, faster EV chargers).

Common NZ residential power connections:
Note kVA is a measure of capacity roughly equal to kW (depends on power factor)

Single phase 63A (Most common, I have this in my house): 14.5kVA
Single phase 100A (rare): 23kVA
Two phase 63A (more common in larger houses, my parents have this): 29kVA
Three phase 63A (less common, but desirable): 43.5kVa

Three phase power will involve 3x active wires coming in from the street (in addition to a natural wire, and the earth rod in the ground). Each active has power in a sinusoidal wave that is 120 degrees out of phase with the others.

Your sparkie will sort this out for you, but best practice is to spread your loads over the phases. As others have said, running three phase power to both houses is ideal.

Regarding EV charging, for ultimate future proofing, you would want to make a 32A three phase connection available. If you going to have more than one EV, the choice would be between 2 three phase 16A connection points, or 2/3 single phase 32A connections, or smart EVSE's that will allocate power between themselves. No need to make this decision now, but running 3 phase 32A cable to each carpaking spot near construction would make things easier for the future.

gchiu:

Now, I'm told that we need to move from Flick to someone else since Flick doesn't have the agreements in place for us to do all of this changing of the power. And I'll need to find a company that can give me a cheap night rate in case I need to recharge the solar batteries. More research :(

I assume this is if you go for an off grid setup, rather than increasing the capacity of your connection.

Firstly heaps of companies offer night rates, so you don't have to be with flick. (google ev charging discount. Generally this applies to all overnight power, or Day/night rate)

Secondly, as long as the other house is electrically off grid, no need to even tell your power provide about it.

The last off grid house I stayed at (on great barrier island) had "outback" branded inverter charger. This had a "generator input", which allowed the batteries to be charged by 230V. You could simply use an extension cord to the main house with a timer for this application. (or the hardwired equivalent). Note that this house had lead acid deep cycle batteries (most cost effective options). Note lead acid batteries can waste 1/3 of their power to the Peuket Law. I.e. put in 1kWh of electricity, get out 0.7kWh of electricity, so charging off peak is going to cost more than just using power in real time.

richms:

What EVs support 3 phase? I recall a friend had a hell of a time driving around and charging at industrial places because the stupid clipsal 56 sockets everywhere seems to deploy often have no neutral in them so the adapter cables were worthless.

When I asked about getting 3 phase here, it was $$ heaps, and I was going to have to upgrade all my breakers and stuff because they dont have a large enough big number on them for an upgraded supply, and that meant RCD for them all and much more hassle, so if I do get more supply here I will just be getting a second one to the garage/shed and not touching the house.

3 phase EV's:

Renault Zoe (32A / 63A depending on vairant)
Tesla Model S/X (16A /24A /32A depending on vairant. (16A is "single charger", 32A is "dual charger", currently those option have been dropped, and all cars support 24A)
BMW i3 (94Ah, 2017+, excl japan import) (16A 3 phase, or 32A single phase by internal bridging)
Merc B class electric (16A)
Smart ED 2017+ (32A 3 phase optional)

As others have noted, this list will likely get longer as batteries get bigger. That said, used import EV's from japan will remain single phase. (3 phase power is rare in japan, and they have adopted the J-1772 (type-1) plug standard that only supports single phase charging.

Regarding 3 phase impact on OP, depending on the specs and spare space of their current main board, it could be more cost effective to just make a new Main board out by the meter, and have a sub-main to each house. Hopefully their sparky will advise options.

gchiu:

Is this doable at all? Or should we just bite the bullet and get a separate pole connection?

Advantage of a separate pole connection is billing. If you go to both houses, or you kid moves out, and you want to subdivide and sell that house (I don't know if subdivision is feasible), the it would be more attractive to buyers if each house had it's own power connection.

If you wanted to let the smaller house, you be best to include power with rent. (otherwise you need to put in really good metering etc).

Big advantage of a single connection is you save on line fee's, $1.20 a day at the moment on standard user plans. Also being on standard user rate means you get a lower per kWh fee than the low user rate.

I don't think it is worth going for a battery setup to save cira $6k capital cost to upgrade capacity to the main house. That stuff isn't cheap. Plus capacity is low. definitely couldn't have tumble dryer unless you shelled out big time for battery capacity. Also off grid stuff is bulky. In a 50m^2 footprint, space would be at a premium.

gchiu:

The plan was to use batteries to keep the load from her house low so that it doesn't impact on mine.... Water is going to be instant gas by LPG.

...

The current house is all electric except the stove which is on LPG. We decided a couple of years ago to rip out all the gas heaters as they were all unflued, and move to far infrared.

Is the plan to stick with gas cooking / hot water in the new house if their was reasonable electrical capacity?

How is gas supplied to the house currently? I ask for two reasons. The first, is that if it is BBQ bottles, that is an expensive, inconvenient way to buy energy (somewhat mitigated by that cooking alone doesn't use much). If it is a 2x45kg bottle set, then you should note that you aren't permitted to have more than 100kg of LPG on one site without a location cert. (you really don't want to go their), so will need to pipe LPG between the houses.

While you are checking out utilities, might be a prudent to review the gas situation. If you have natural gas in the street, getting connected could be cost effective. Daily charges are higher than LPG bottle rental, and kWh cost is generally much lower. If you are splitting costs across two houses, the daily fee becomes less important.

https://www.vector.co.nz/personal/get-connected/gas-estimator

How do you find the "far infrared" heating in your house? - Is the long term plan to stick with this, or move to flued gas / heatpumps / central heating?

What is the plan for space heating in the new house?

Why I ask is that flued natural gas heating can have lower capital cost, and similar (real world) operational costs to heat-pumps while running quieter, and creating less drafts. Of course most people go for heat pumps that can also cool in summer these days).

gchiu:

.... And hopefully the architects will have done the job correctly so that she won't any or much space heating.

That may be ambitious. Are you going full passive house with this? (that would mean you can get away with only 500W heating capacity). A typical 50m^2 house would need 6kW odd of heating.

I would advise provisioning for either a heat pump, or flued natural gas heater (only if you can get natural gas) before construction. (no need to buy yet, just have the wires etc run).

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#2048672 4-Jul-2018 00:40

Good explanation above. I am in favor of separate connection.

Plans change all the time. It is much better to have separate just in case for moving/renting/selling in the future etc.

Please don't go for solar system. It is still pricey at this stage.

Linuxluver

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#2048679 4-Jul-2018 03:44

gchiu:

The distance from my switch board to her house would be about 30m.

Good idea on using gas for the kettle.

What about the other appliances? She's thinking of getting a combination washer/condensor dryer.

She can use a Dyson stick vacuum cleaner.

How does 3 phase power help? ( I'm not that conversant with this stuff ).

No plans on renting out. When we get older, and she starts a family I suspect we'll just swap houses.

Gas connections are expensive. You're probably better to just get a separate power connection from the pole. I did it at a house in Auckland and I think it was about $700. I can't see anyone trench gas for 30m+ for less than three times that. I wouldn't use a gas bottle......as unflued gas burning produces CO and water.......headaches and mold from condensation.

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gchiu

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#2048694 4-Jul-2018 07:27

Aredwood: Surprised that you are not simply connecting 3 phase to both houses. Is that to avoid a switchboard upgrade in the main house?

I wasn't offered that option. And I do have a new switchboard put in only 3 years ago.

I can ask them but I suspect they're going to say it's going to cost a lot more.

gchiu

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#2048704 4-Jul-2018 08:05

Scott3:

While I love off grid setup's, they don't really work financially unless connection costs to the grid are $40k+.

I wasn't able to get the new pole connection cost but I'm assuming it is also well below $6k.

Scott3:

First thing to note is that WEL (I assume you are in WEL's area) doesn't seem to charge extra daily fees for larger capacity or 3 phase connection's (untill you hit 110kVA, you would be 43kVA). This differed from lines companies in other regions that charge more daily fees for more capacity (sometimes heaps more).

Useful to know.

Scott3:

Three phase power will involve 3x active wires coming in from the street (in addition to a natural wire, and the earth rod in the ground). Each active has power in a sinusoidal wave that is 120 degrees out of phase with the others.

Your sparkie will sort this out for you, but best practice is to spread your loads over the phases. As others have said, running three phase power to both houses is ideal.

Not suggested by them to me. I will ask but I am planning on still have solar panels on the roof so not sure how that would affect things. Someone is often home during the day so we can use the power.

Scott3:

Regarding EV charging, for ultimate future proofing, you would want to make a 32A three phase connection available. If you going to have more than one EV, the choice would be between 2 three phase 16A connection points, or 2/3 single phase 32A connections, or smart EVSE's that will allocate power between themselves. No need to make this decision now, but running 3 phase 32A cable to each carpaking spot near construction would make things easier for the future.

They said they can run the 3 phase connection to the garage in the future when I actually get the EV. Perhaps I should ask for it now.

Scott3:

gchiu:

Now, I'm told that we need to move from Flick to someone else since Flick doesn't have the agreements in place for us to do all of this changing of the power. And I'll need to find a company that can give me a cheap night rate in case I need to recharge the solar batteries. More research :(

I assume this is if you go for an off grid setup, rather than increasing the capacity of your connection.

Flick apparently said that they can't get the wires from the pole changed. I have to change providers to another company that can arrange it. PV company says to try Ecotricity but they might be another virtual power company. I'll ring them.

Scott3:

Advantage of a separate pole connection is billing. If you go to both houses, or you kid moves out, and you want to subdivide and sell that house (I don't know if subdivision is feasible), the it would be more attractive to buyers if each house had it's own power connection.

If you wanted to let the smaller house, you be best to include power with rent. (otherwise you need to put in really good metering etc).

Big advantage of a single connection is you save on line fee's, $1.20 a day at the moment on standard user plans. Also being on standard user rate means you get a lower per kWh fee than the low user rate.

The metering should work.

Scott3:

I don't think it is worth going for a battery setup to save cira $6k capital cost to upgrade capacity to the main house. That stuff isn't cheap. Plus capacity is low. definitely couldn't have tumble dryer unless you shelled out big time for battery capacity. Also off grid stuff is bulky. In a 50m^2 footprint, space would be at a premium.

The batteries were going to be in the basement of the main house.

Scott3:

How is gas supplied to the house currently? I ask for two reasons. The first, is that if it is BBQ bottles, that is an expensive, inconvenient way to buy energy (somewhat mitigated by that cooking alone doesn't use much). If it is a 2x45kg bottle set, then you should note that you aren't permitted to have more than 100kg of LPG on one site without a location cert. (you really don't want to go their), so will need to pipe LPG between the houses.

It will be 2 x 45 Kg bottles. We might tap the cooking gas off those bottles and dispense with the existing 2 x 9 Kg bottles we use at the main house.

Scott3:

While you are checking out utilities, might be a prudent to review the gas situation. If you have natural gas in the street, getting connected could be cost effective. Daily charges are higher than LPG bottle rental, and kWh cost is generally much lower. If you are splitting costs across two houses, the daily fee becomes less important.

https://www.vector.co.nz/personal/get-connected/gas-estimator

I was thinking of buying my own gas bottles. I already own 18 and 27 kg bottles. Are the 45 kg bottles rented?

The plan was originally to connect to the gas meter on the property .. but when the time came, we found they had removed it! Using googlemaps allowed us to find where it had been, and what was left.

We can look at that option again, but my stove has already been converted to LPG.

Scott3:

How do you find the "far infrared" heating in your house? - Is the long term plan to stick with this, or move to flued gas / heatpumps / central heating?

Why I ask is that flued natural gas heating can have lower capital cost, and similar (real world) operational costs to heat-pumps while running quieter, and creating less drafts. Of course most people go for heat pumps that can also cool in summer these days).

I think even though it was professionally installed, it was undersized so we still need supplemental convection heaters in winter. It's nice having the heat from above, and I don't like heat pumps which move hot air onto your body. So, for the moment we'll stick with the far infrared ( which is why the house power sums up to over 100 amps ! ).

I had gas central heating at my old house with Nova. It was too expensive to run. And we don't need cooling in Summer in Wellington quite yet!

Scott3:

That may be ambitious. Are you going full passive house with this? (that would mean you can get away with only 500W heating capacity). A typical 50m^2 house would need 6kW odd of heating.

No, not full passivhaus. But the architect reckons that she won't need space heating. Or, maybe just a couple of far infrared heaters. I haven't seen the heat modelling done but the walls are going to be insulated cassettes etc. And we're going to prewire for a couple of heaters.

Scott3

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#2048915 4-Jul-2018 12:42

Ultimately the way the phases are configured arn't that important in a residential setting. More of a technical interest. (most houses just have 1 or 2 phases, so power companies are balance phase by spreading houses around each phase).

If you go for grid tie solar, it can be a little more challenging to optimize your setup. My understanding is that the issue is that if you have your grid tie setup on the red phase, but draw all your power from the white phase, the power company will pay you cira 7c/kWh for the power sold on red, and charge you 15c/kWh for power purchased on blue. If your solar setup was meeting your load, you would simply be avoiding purchasing power at 15c/kWh. (unless you go for microinverters, spreading your solar generation around phases means you need an inverter for each phase)

gchiu:

They said they can run the 3 phase connection to the garage in the future when I actually get the EV. Perhaps I should ask for it now.

I would only bother if there is any cost saving to doing it now (i.e. walls / trenches are open). Otherwise, you can just ask that space be provisioned on a circuit board for it.

gchiu:

It will be 2 x 45 Kg bottles. We might tap the cooking gas off those bottles and dispense with the existing 2 x 9 Kg bottles we use at the main house.

....

I was thinking of buying my own gas bottles. I already own 18 and 27 kg bottles. Are the 45 kg bottles rented?

The plan was originally to connect to the gas meter on the property .. but when the time came, we found they had removed it! Using googlemaps allowed us to find where it had been, and what was left.

We can look at that option again, but my stove has already been converted to LPG.

You would need to hold a location test certificate to legally have more than 100kg of LPG on your property.

LPG in 9kg bottles is very expensive, LPG in 45kg bottles is similar to low user power, Natural gas is about 1/2 to 1/3 the cost of power per kW.

Normally converting stoves etc is fairly easy, simply a matter of the gasfitter screwing in a different size injector

45kg bottles are typically rented, but the rental fee is quite reasonable. (much cheaper than natural gas daily fee).

I would do a cost evaluation on this. If cheap natural gas is available in the street, why pay for more expensive LPG (of course this needs to be weighed up against connection fees, and daily fees). Natural gas is also more convenient. - no need to take 9kg LPG bottles to the gas station, or to arrange for 45kg bottle's to be filled or swapped. Also no having your hot water cut out if you have a manual changeover...

gchiu:

I think even though it was professionally installed, it was undersized so we still need supplemental convection heaters in winter. It's nice having the heat from above, and I don't like heat pumps which move hot air onto your body. So, for the moment we'll stick with the far infrared ( which is why the house power sums up to over 100 amps ! ).

Restive electric heaters cost 3 times what a heat pump or flued natural gas heater does. The question is that with the infrared heater, how much less heat can you get a away with.

Flued gas heater's heat a much lesser volume of air much hotter than heat pumps, so you get less of the "draft" issues.

Also I have found flour mounted heatpumps generally nicer than high wall ones for blowing air around. (that said, I have a high wall unit in my house to save

gchiu:

No, not full passivhaus. But the architect reckons that she won't need space heating. Or, maybe just a couple of far infrared heaters. I haven't seen the heat modelling done but the walls are going to be insulated cassettes etc. And we're going to prewire for a couple of heaters.

It would be unusual to see a house with zero space heating requirements, especially in wellington, a city known for adverse weather... I would consider more efficient heating methods than far infrared for a new house.

Linuxluver:

Gas connections are expensive. You're probably better to just get a separate power connection from the pole. I did it at a house in Auckland and I think it was about $700. I can't see anyone trench gas for 30m+ for less than three times that. I wouldn't use a gas bottle......as unflued gas burning produces CO and water.......headaches and mold from condensation.

Historically utility companies would cover the cost of gas connections, I don't know if this is the case. Anyway vector's estimator tool recons that it would cost $1800 to get gas to my house, or $500 if I provide the trench.

Sounds like OP may be trenching gas between the houses anyway, so may have the gear on site to do trenching.

https://www.vector.co.nz/personal/get-connected/gas-estimator

Regarding the gas bottle, the combustion gases are the same for LPG bottles and natural gas. Also, OP is only proposing to use gas for hot water (exhaust's gasses outside) and the cooktop (Typically under a rangehood to collect cooking smells and water vaper also). Unfunded gas space heating has gone out of fashion now for the reason's you mention.

My house in auckland is electric only. This is not a bad option these days. Electric hot water cylinder last a long time (can be solar thermal with electric backup if you want), and mean we get a lesser power rate as power companies can shed that load if required. I have induction cooking, and a heat pump + portable heaters for space heating.

In the last house where we had natural gas, the savings from it being cheaper than power typically matched the connection fee's... Of course OP is already somewhat committed to go with gas of some sort.

gchiu

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#2048952 4-Jul-2018 13:38

http://silenth.net/hpsw/wp-content/uploads/2017/10/verco-1.pdf

The study shows that Infranomic infrared heating panels offer a valid alternative to other heating solutions as
IR panels can produce human comfort conditions in a heated space at lower air temperatures and with less
thermal gradient within the space and less infiltration heat loss. These factors combine to allow IR panels to
offer lower energy consumption, lower carbon emissions and lower running costs than either storage heaters
or air-source heat pumps.

I'm not sure I believe this now but that was one of the deciding factors when we chose to go far infrared to heat the existing 1940s house.

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#2049179 4-Jul-2018 18:47

gchiu:

http://silenth.net/hpsw/wp-content/uploads/2017/10/verco-1.pdf

The study shows that Infranomic infrared heating panels offer a valid alternative to other heating solutions as
IR panels can produce human comfort conditions in a heated space at lower air temperatures and with less
thermal gradient within the space and less infiltration heat loss. These factors combine to allow IR panels to
offer lower energy consumption, lower carbon emissions and lower running costs than either storage heaters
or air-source heat pumps.

I'm not sure I believe this now but that was one of the deciding factors when we chose to go far infrared to heat the existing 1940s house.

A couple of notes:

The comparison to storage heaters is done on a per-kWh basis. The whole point of a storage heater is that each kWh is significantly cheaper (either day/night rates, or even cheaper ripple-control). They appear to have totally ignored this.
A SEER/COP of 2.0 for an air-sourced heat pump is pathetic. Modern ones are about 3.5-5, depending on capacity and price point.

40A three phase supplies (~22kVA) are also not uncommon, but you have to be careful with balancing. A large single-phase load like an electric car or outbuilding could scupper this.

I'm surprised that breaker rupturing capacity is an issue. Are they only 3kA? 4500A should be enough for any domestic supply.

gchiu

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#2061812 24-Jul-2018 17:03

A hiccup in the install. I changed from Flick to energyclubnz as Flick told my electrician they don't have the contracts in place with Wellington Electricity to allow them to ask for the change to 3 phase power, and to organize the new meter.

Now it seems that energyclubnz are new to the process as well, and can't give pricing as they're also waiting to hear back.

Perhaps I should switch to another company right now to expedite things. My solar installer suggested Ecotricity.

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