NZ reaches Household electrification tipping point

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#3210150 24-Mar-2024 14:36

Mehrts:

The thing that really irks me is the daily charge for natural gas mains. In the Manawatu, you're looking at ~$1.50 per day, however the cost per unit of gas is ~7c/kWh.

...

Since gas is relatively cheap per unit used, it makes sense for higher users of gas. However for smaller households such as mine, it doesn't. If I was starting from scratch with a property, I wouldn't install gas mains.

With regards to daily charges infrastructure isn't cheap especially for something that can blow up if not carefully maintained.

What irks me is the use of kWh for measuring gas by suppliers, when it's also presented along side electricity usage.

For the following reason:

If you get 1kWh of electricity and feed it into a resistance heater (say hot-water tank) you get ~= 1kWh of heat generated
If you get 1kWh of electricity and feed it into a Heat pump with a COP of 3 you get ~= 3kWh of heat
If you use 1kWh of gas in a hot-water tank you get 0.6-0.85kWh of heat

So if you are comparing gas vs electricity and your energy use is recorded in kWh for both this needs to be taken into account:

Gas stove tops are apparently 40% efficient
Gas hot water 60-85% efficient
Gas heater again 60-85% efficient
Heat pump 300-400% efficient
Induction stove 90% efficient

Say we wanted the following amounts of heat:

1kWh to cook a meal
3kWh to heat water for several showers
6kWh to heat the room

That needs ~4kWh of electricity with heat-pumps (~10kWh if resistive), or 13-17 kWh of gas. So unless people know this they make incorrect calculations of how much they will spend on electricity compared to gas.

Inphinity

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#3210419 24-Mar-2024 21:26

Where are they getting their 5.5% finance? Even most mortgage rates aren't that low atm, and the <=1% rates by some banks don't necessarily allow for things like converting gas hot water to electric etc.

eonsim

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#3210423 24-Mar-2024 21:34

Inphinity:

Where are they getting their 5.5% finance? Even most mortgage rates aren't that low atm, and the <=1% rates by some banks don't necessarily allow for things like converting gas hot water to electric etc.

According to the finance section that is the 10 year average mortgage rate reported by RBNZ, so they're using a longer term average rate rather than the current rate or trying to guess what it might be in a couple of years. The 1% rate varies with bank westpac allows heatpump hot water upgrades along with certain log burners, normal heatpumps, insulation, double glazing, solar, batteries and EVs.

cddt

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#3210451 25-Mar-2024 08:57

eonsim:

This report is arguing that the savings do stack up even with needing to put it on a mortgage...

I have trouble relating it to my individual situation because I'm not in the market for a new car. The report seems to compare buying a new ICE car with buying a new EV. It would be interesting to see used ICE vs used EV.

As for replacing domestic gas appliances with electrical, I am very keen to do this but the up front cost and practical aspects make it difficult. Right now the mortgage is uncomfortably large and I would rather bring it down faster than load up household improvements on it. At a rate of 6.85% (just re-fixed a couple of weeks ago), getting some breathing room on the mortgage is more important.

My referral links: BigPipe | Mercury

richms

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#3210453 25-Mar-2024 09:43

gzt:

During the selection process I learned a lot about induction hobs. They don't need to consume more power than a standard electric hob.

Yeah, they will cap the consumption across all the elements to what you limit them to so you can get a decent amount of power out of one of them which is all you generally need. Still way better than the junk glass with a glowing bit of wire under it that was all the rage for a while and completely useless for anything other than boiling cabbage slowly.

Richard rich.ms

johno1234

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#3210458 25-Mar-2024 09:58

Agreed. Our kitchen has a ceramic hob and I hate it. Will swap out for a same size induction one eventually.

boosacnoodle

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#3210470 25-Mar-2024 10:31

Bung:

Wait until the price of electricity starts climbing. There was a recent report about the Cook Strait cable being end of life and the options ranging between $400M to $3B.

User pays, I say. South Island energy prices looking mighty cheap right about now.

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Bung

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#3210499 25-Mar-2024 11:51

There have been other parts of distribution network that have had the overdue for upgrade mention. When the price goes up they'll say you've been warned. South islanders might get cheaper power but users pays also works getting goods from the North.

boosacnoodle

963 posts

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#3210505 25-Mar-2024 12:01

Mehrts:

The thing that really irks me is the daily charge for natural gas mains. In the Manawatu, you're looking at ~$1.50 per day, however the cost per unit of gas is ~7c/kWh.

During the summer months, I'm paying $45 connection charge for the month, just to use $10 of gas. Winter is a different story though. My usage is right on the threshold of the low & standard gas user rates, so there's no benefit to changing plans.

Since gas is relatively cheap per unit used, it makes sense for higher users of gas. However for smaller households such as mine, it doesn't. If I was starting from scratch with a property, I wouldn't install gas mains.

The pipes are still there and need to be paid for (maintained) whether you use them or not.

gzt

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#3210510 25-Mar-2024 12:06

cddt: As for replacing domestic gas appliances with electrical, I am very keen to do this but the up front cost and practical aspects make it difficult.

A family friend electrician recommended we go surface mount for the cable with square conduit and sort that out later if we want to. That made things quick for our scenario. It's one of those things you don't notice unless you're looking directly at it.

MikeAqua

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#3210524 25-Mar-2024 12:45

In the new build we will have an LPG wok burner and miniature hot plate plus an induction hob in the indoor kitchen. Central heating/cooling connected to a ground to water heatpump. Another sizeable ground to water heatpump for the pool. Big solar array and a battery bank to match. It's possible the ground loops for the heat pumps will actually go into ponds that are on the site. I'm gathering water temperature data this winter.

In the outdoor kitchen we will have an LPG hotplate (probably a Blackstone), DIY woodfired offset grill and a charcoal Kamado kettle BBQ/tandoor. Plus, a firepit for sitting around and making stews (Feijoada, Poki etc).

Cars are wait and see. The oldest everyday type car is only nine years old. We also have an older sportscar, but I'm not selling that while I'm young enough to safely drive it 👿

Mike

MikeAqua

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#3210538 25-Mar-2024 13:02

gzt:
A family friend electrician recommended we go surface mount for the cable with square conduit and sort that out later if we want to. That made things quick for our scenario. It's one of those things you don't notice unless you're looking directly at it.

An electrician suggested that to us for our current place, when we were looking at replacing our gas hob with induction (currently cable to hob is 10A).

I bought some surface conduit and affixed it to a corner one end of the splashback with double sided tape. The splashback has a printed image, so painting the conduit to match wasn't an option. We left it there for a month and decided we hated it. We still have a gas hob.

Mike

Mehrts

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#3211384 26-Mar-2024 19:53

boosacnoodle:

The pipes are still there and need to be paid for (maintained) whether you use them or not.

Yes, I know...

It's more the cost of the service vs the amount used for my particular application vs the electrical equivalent. Hence my comment regarding not going with gas for future builds.

dustysmurf

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#3211461 26-Mar-2024 21:14

gzt: Recently replaced gas hob with induction hob.
During the selection process I learned a lot about induction hobs. They don't need to consume more power than a standard electric hob.

Can you provide details of what induction hob you went for, as i'm looking to disconnect the gas, so what to replace the gas hob with induction, and gas hotwater with heat pump.

But I want to do the entire switch with solar panels install, batteries, and 8-10K hybrid inverter at the same time.

Also, thank you to everybody that shares their quotes in the solar thread, And what inverters they end up going with (or upgrading from/to)

sir1963

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#3211575 27-Mar-2024 13:24

Just wait until people realise that Electricity is a finite resource too.

The neat thing about heat pumps is that they can cool a house down, so that means they get used during summer as well as winter, ie usage goes UP and our hydro lake levels fall.

Electric cars will also add to the consumption. Add in a few data centres , climate change , and we are looking at a power shortfall.

About 80% of our NZ energy consumption is via fossil fuels, and as much as applaud getting rid of them, the reality is we are not replacing the fossil fuel energy source with an equivalent volume/availability.

Think about it, we need to triple /quadruple our electricity production just to maintain current energy usage if we go all electric, and the time that this will take we will need to have doubled it again by then just to keep up with growth/demand.

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