Attn home builders /renovators. Climate change commission to ban natural gas

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#2715958 31-May-2021 09:28

The house I am thinking of was built last year. I would have preferred the house have a heat pump underfloor heating system - They had a massive 20kw (72x280w panels) solar array and underfloor heating in a large concrete pad can stay warm for days.
Problem with the particular system was no dump load for excess solar once the batteries were full.

Hydro is still a problem as lake levels do indeed get low - until Tiwai point closes and there is grid capacity to redirect that power. Building new hydro is a problem with cultural and political barriers - In Hawkes bay the ruataniwha scheme was cancelled recently for those reasons.

Pumped hydro can also supply a dump load for oversupply and frequency correction without encouraging people to buy batteries / power walls for their houses which have the recycling issues. In Australia they have issues with over supply on the grid due to all the solar - a pumped hydro system could suck up a big amount of that excess.

Yes in the area to the south/west of lake taupo, because many of the consumers are seasonal, the lines company charges based on peak demand as they cant recover enough through a per-unit tariff to keep the network viable and fair for the all-year-round consumers. Its quite interesting when you look at the varied ways lines companies charge across NZ.

Ray Taylor

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raytaylor

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#2715961 31-May-2021 09:33

Scott3:

Should note that while Onslow could do daily peaking it's main purpose would be to provide dry year reserves without needing fossel fuels.

Daily peaking would mean less evening draw on the lakes, so the lake levels stay higher, further into the dry season. So same result I guess.

Scott3:

They just bid in at zero in the stack, so almost all way's get dispatched (market works so that everybody gets paid the clearing price, not their bid price

That makes sense :-)

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Fred99

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#2715979 31-May-2021 09:48

Based on 3 months use per 9kg bottle, our gas hobs release about 150 grams of CO2 a day.

That's about the amount of CO2 a car releases travelling the first 1/2 km, or about the amount released producing the steel that a can of baked beans came in.

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#2715980 31-May-2021 09:50

raytaylor:

Building new hydro is a problem with cultural and political barriers - In Hawkes bay the ruataniwha scheme was cancelled recently for those reasons.

The scheme was cancelled because a small group of farmers and politicians representing vested interests used underhanded tactics to try to sneak it around a proper democratic decision-making process. Although there were real problems with the scheme as proposed (such as a so-called 'land swap' to enable flooding of protected land and other devious sleight-of-hand procedures), the main objection to the project was not the dam as such, but the back room way the process was being conducted.

Plesse igmore amd axxept applogies in adbance fir anu typos

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#2716041 31-May-2021 11:05

ah farmers. how many gas appliances and cars we have to remove so farmers can grow one cow ... anyone knows

Scott3

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#2716043 31-May-2021 11:13

Batman:

ah farmers. how many gas appliances and cars we have to remove so farmers can grow one cow ... anyone knows

Tricky bit for NZ is that getting rid of animal agriculture (especially dairy), basically means we would end up very poor as a country. That industry contributes a fairly massive amount to out exports, and has really high GDP contribution per worker (opposite of tourism).

As such, chasing the lower hanging fruit like Emissions from burning coal, gas, petrol etc. is relatively more attractive.

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#2716099 31-May-2021 11:30

so instead of removing the elephant in the room we sweep all the dust mites from the floor

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#2716100 31-May-2021 11:31

raytaylor:

The house I am thinking of was built last year. I would have preferred the house have a heat pump underfloor heating system - They had a massive 20kw (72x280w panels) solar array and underfloor heating in a large concrete pad can stay warm for days.
Problem with the particular system was no dump load for excess solar once the batteries were full.

Hydro is still a problem as lake levels do indeed get low - until Tiwai point closes and there is grid capacity to redirect that power. Building new hydro is a problem with cultural and political barriers - In Hawkes bay the ruataniwha scheme was cancelled recently for those reasons.

Pumped hydro can also supply a dump load for oversupply and frequency correction without encouraging people to buy batteries / power walls for their houses which have the recycling issues. In Australia they have issues with over supply on the grid due to all the solar - a pumped hydro system could suck up a big amount of that excess.

Yes in the area to the south/west of lake taupo, because many of the consumers are seasonal, the lines company charges based on peak demand as they cant recover enough through a per-unit tariff to keep the network viable and fair for the all-year-round consumers. Its quite interesting when you look at the varied ways lines companies charge across NZ.

do the batteries degrade over time like li ion?

Scott3

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#2716101 31-May-2021 11:32

raytaylor:

The house I am thinking of was built last year. I would have preferred the house have a heat pump underfloor heating system - They had a massive 20kw (72x280w panels) solar array and underfloor heating in a large concrete pad can stay warm for days.
Problem with the particular system was no dump load for excess solar once the batteries were full.

Hydro is still a problem as lake levels do indeed get low - until Tiwai point closes and there is grid capacity to redirect that power. Building new hydro is a problem with cultural and political barriers - In Hawkes bay the ruataniwha scheme was cancelled recently for those reasons.

Pumped hydro can also supply a dump load for oversupply and frequency correction without encouraging people to buy batteries / power walls for their houses which have the recycling issues. In Australia they have issues with over supply on the grid due to all the solar - a pumped hydro system could suck up a big amount of that excess.

Yes in the area to the south/west of lake taupo, because many of the consumers are seasonal, the lines company charges based on peak demand as they cant recover enough through a per-unit tariff to keep the network viable and fair for the all-year-round consumers. Its quite interesting when you look at the varied ways lines companies charge across NZ.

That's already a fairly massive & expensive solar system, and getting rid of the diesel boiler would require it be bigger still - Peak demand for heating is in the middle of winter, when sunshine hours are lowest, so solar system would end up massively overbuilt for summer (or see quite a bit of generator run time in winter).

Perhaps with such a big array, a backup generator was omitted.

Potentially a clever outcome from an energy perspective would be heat pump setup, with heat recovery off the generator. In fringe seasons the heat pump would take care of most of the work, and in the middle of winter the system would function as co-gen, with the generator producing both heat and power. - still using fossil fuels though.

[edit] In term's of dump loads, we don't really have need for this on the NZ grid. Much of our power generation is hydro, and if there is insufficient load, the wicket gates can be closed, and the schemes can stop contributing power, same for wind, where the blades can be feathered.

In markets with a lot of combined cycle thermal plants (fossil fuel / geothermal / nucular), they take many hours or day's to ramp back up if shut down or doped bellow a certain output level. In these markets wholesale power prices can go negitive, as such power plants literally pay people to take power away so they can stay online for the next peak time.

raytaylor:

Daily peaking would mean less evening draw on the lakes, so the lake levels stay higher, further into the dry season. So same result I guess.

Better to use hydro resources directly in the first instance. They get topped up for free by the rain. Making power to pump water to onslow is always going to be less efficient than just holding back the water in say lake taupo, and running the scheme at peak times only...

Either way, with or without Onslow, we are going to need a lot more renewable generation. Large hydro seems fairly unlikely at this stage (although if we got desperate we could bring a couple of proposals back from the dead). I think the heavy lifting will come from New Geothermal, and wind schemes, with a bit of smaller "run of the river" (no big dam) hydro, and a bit of solar on rooftops.

We are going to need a lot of the above. Getting rid of the smalter frees up about 5000GWh/year, which is roughly capacity of the Huntley power station. In addition I guess we will need the addition or roughly two plus Manapouri power stations worth of capacity to be newly built (10,000GWh/year+) to get rid of the other fossil fuel power plants, and to start making inroads into moving stuff like transport, and industrial process heat off fossil fuels to electricity.

Fred99

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#2716103 31-May-2021 11:34

Batman:

ah farmers. how many gas appliances and cars we have to remove so farmers can grow one cow ... anyone knows

Back of envelope:

A cow emits about 100kg methane per annum ~= 2,800kg CO2 E

~ 1900kg LPG or ~ 1200 litres of petrol

So about 4 9kg gas bottles a week, or about 6 months average motoring in a petrol car.

Poisoning of groundwater and destruction of waterways are other issues that need to be sorted with diary farming in NZ.

However it's pointless if NZ did it alone - when if we reduced dairy cow numbers for example, another country would simply increase production - and there would be zero global benefit (and possibly worse, as overseas dairy production uses less efficient feed production.

1101

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#2716105 31-May-2021 11:38

Scott3:

Batman:

ah farmers. how many gas appliances and cars we have to remove so farmers can grow one cow ... anyone knows

Tricky bit for NZ is that getting rid of animal agriculture (especially dairy), basically means we would end up very poor as a country. That industry contributes a fairly massive amount to out exports, and has really high GDP contribution per worker (opposite of tourism).

and poor/bankrupt counties can only afford the cheapest energy options : coal , gas, petrol etc.
So getting rid of all the cows and sheep will make things worse in the long term

Tourism also relies only greenhouse producing planes & ships . So a double whammy

Scott3

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#2716107 31-May-2021 11:43

Batman:

do the batteries degrade over time like li ion?

Basically all on grid home storage batteries are Li Ion, so yes they degrade exactly like a Li ion battery...

Still the batteries are designed for this application so do OK. I think a tesla powerwall is warranted for 10 year's / 3200 cycles, with a End of Warranty capacity of 70%.

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#2716111 31-May-2021 11:44

Scott3:

Either way, with or without Onslow, we are going to need a lot more renewable generation. Large hydro seems fairly unlikely at this stage (although if we got desperate we could bring a couple of proposals back from the dead). I think the heavy lifting will come from New Geothermal, and wind schemes, with a bit of smaller "run of the river" (no big dam) hydro, and a bit of solar on rooftops.

Geothermal is not even remotely as clean as people think

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#2716113 31-May-2021 11:47

Fred99:

H2 can be used to produce methane or "synthetic natural gas" from CO2. So long as the H2 is produced using zero carbon emission electricity generation, and you're not burning fossil fuel to generate the CO2, the system is carbon neutral.

Why? You have to input energy into the system somewhere, presumably electricity for electrolysis. Every time you change energy from one form to another (e.g. from electricity to H2, or from H2 to CH4, CH4 to CO2) you lose some... that is the 2nd law of thermodynamics. Unless you have some horrendous supply issue, it's more efficient (and vastly cheaper) to just use electricity.

Fred99

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#2716120 31-May-2021 11:59

frankv:

Fred99:

H2 can be used to produce methane or "synthetic natural gas" from CO2. So long as the H2 is produced using zero carbon emission electricity generation, and you're not burning fossil fuel to generate the CO2, the system is carbon neutral.

Why? You have to input energy into the system somewhere, presumably electricity for electrolysis. Every time you change energy from one form to another (e.g. from electricity to H2, or from H2 to CH4, CH4 to CO2) you lose some... that is the 2nd law of thermodynamics. Unless you have some horrendous supply issue, it's more efficient (and vastly cheaper) to just use electricity.

Because generation capacity to meet peak energy demand is potentially wasted (ie from wind, solar, hydro) when off-peak unless you find some means for storage, be that pumped hydro, batteries, or conversion to other useable fuels. All storage methods have losses. Liquid fuels are very useful because of very high energy density, if you can make them in a carbon-neutral way then it's a way to solve a problem.

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