Building a new house, being prepared

[Vostok]

I have three batteries. I didn't buy any of them to save money but because it is the right thing to do for the environment. Same reason I bought my Model 3, not to save money but it is the right thing for the environment.

Well, I admire the motivation, as it was similar to mine, but a battery merely timeshifts solar. If you don’t have a battery, your excess solar is exported to the grid, which has the effect of making the grid cleaner since it displaces fossil generation.

So all the battery is doing is changing who gets to use your excess solar. Is it primarily you (battery), or is it your neighbours (no battery)? In environmental terms, who uses the excess solar is irrelevant. It is therefore your solar panels that are creating the environmental benefit, not the battery.

The only exception to this is if people are off-grid and a battery eliminates the need to use a diesel generator when solar production is zero.

So that reduces the role of the battery to an economic one - does it save money, either directly though reduced power bills due to timeshifting, or indirectly through providing you uninterrupted power hence ability to earn income or not have your business disrupted if there’s a grid outage.

There might also be intangible emotional or philosophical reasons for wanting a battery.

 

[paulp]

So had the meeting with the electrician yesterday, but ended up getting more confused than before.
I guess he didnt get when I asked him for 32A 3-phase circuit terminated in either a socket or just a junction box at the garage as suggested by Cafz.
He kept on saying he can do it but how will you charge when you go out or charge at other places.

He also quoted an excess of around a $1000 for the wiring and fixing this 32A circuit switch.Is this justifiable?

And yes I confirmed we do have a 3 Phase connection to our home.

I was thinking to keep things simplified , should I just ask for a 15A socket to be installed at the Garage and charge using the 15A adaptor that would be provided with the car?

Or if I call the Tesla approved electricians and ask them how much they would quote?

I am totally confused at this time, as this is French to me
Thanks

Start with how much you drive each day. If the 15a plug or even 10a plug will cover your driving, then just start with that.

 

[cafz]

I guess he didnt get when I asked him for 32A 3-phase circuit terminated in either a socket or just a junction box at the garage as suggested by Cafz.
He kept on saying he can do it but how will you charge when you go out or charge at other places.

He also quoted an excess of around a $1000 for the wiring and fixing this 32A circuit switch.Is this justifiable?

It sounds like he doesn't realise that there's a charging connector between the car and the wall socket that can have different kinds of connections?

$1000 for an additional 32A 3 phase circuit in a new build seems a little on the high side to me, but maybe it's a decent distance from the switchboard?

If you were getting it terminated at a socket it would be one like this: CLIPSAL EY56C532 EASY56 | 32Amp Switched Outlet 3PH 5 Pin Round IP66

 

[Rolond]

This is the same thing from the same place but a whole lot cheaper:- NLS 66CV532 | 5 Pin 32Amp Combination Switched Socket IP66 Rated CO3PH532

 

[cafz]

Aye it was just an example.

 

[Zoltrix77]

Even is SA which is the 2nd highest renewable state we cannot make enough power at night to avoid using our gas generators. So whatever happens my bbq is going to be cooking with gas. Converting it to electricity first is not as efficient.
As for house heating and cooling, optimum solution is hydronic floor heating/cooling with very good insulation and shaded windows. Most of Australia gets very hot or cold so some good aircon is essential for days when the hydronics cannot cope. Most people undersize their aircon so it runs flat out all the time. An oversized aircon can be more efficient if optimised correctly, but costs more. VRV is incredibly good but its more commercial sized so costs a bit but extremely efficient

Hydronic is great, I just don't think its reactive enough for a lot of Australia, eg, in Melbourne, one day is 20 and the next day is 12. Hydronic seemingly works best is very cold areas where you need consistant heat.

As for requiring gas at night in SA, isn't that the point? Its there any ready when required but not being burnt unless its nescessary and therefore using minimal fossil fuels? As renewable continue to increase, less and less gas is required.

 

[paulp]

Hydronic is great, I just don't think its reactive enough for a lot of Australia, eg, in Melbourne, one day is 20 and the next day is 12. Hydronic seemingly works best is very cold areas where you need consistant heat.

As for requiring gas at night in SA, isn't that the point? Its there any ready when required but not being burnt unless its nescessary and therefore using minimal fossil fuels? As renewable continue to increase, less and less gas is required.

Agree re gas, thats why I think gas hot water in SA is quite efficient if being produced at night compared to using gas fired electricity to produce hot water at night (Or when rooftop solar isn’t 100%). The way to use hydronics is set them up for the average day, and then use your supplementary heating or cooling for the times you need a faster reaction.

 

[paulp]

Well, I admire the motivation, as it was similar to mine, but a battery merely timeshifts solar. If you don’t have a battery, your excess solar is exported to the grid, which has the effect of making the grid cleaner since it displaces fossil generation.

So all the battery is doing is changing who gets to use your excess solar. Is it primarily you (battery), or is it your neighbours (no battery)? In environmental terms, who uses the excess solar is irrelevant. It is therefore your solar panels that are creating the environmental benefit, not the battery.

The only exception to this is if people are off-grid and a battery eliminates the need to use a diesel generator when solar production is zero.

So that reduces the role of the battery to an economic one - does it save money, either directly though reduced power bills due to timeshifting, or indirectly through providing you uninterrupted power hence ability to earn income or not have your business disrupted if there’s a grid outage.

There might also be intangible emotional or philosophical reasons for wanting a battery.

The scenarios you havn’t covered is the benefit of batteries when:
- the power company prohibit export due to too much renewables in part of the system. This means you can store the renewable for later. SA now require this shutdown ability in all new installations.
- there is no benefit to the ‘neighbour’ from My excess solar if the grid is producing 100% renewables for any period of time, which will start happening more often based on your excellent monthly data. In that scenario, there is significant environmental benefit in storage.

Most new solar farms in SA now include storage. I’m sure they are doing it for the environmental gain. The reality is they are also doing it for the financial gain.

 

[Vostok]

The scenarios you havn’t covered is the benefit of batteries when:
- the power company prohibit export due to too much renewables in part of the system. This means you can store the renewable for later. SA now require this shutdown ability in all new installations.

Well we certainly don’t have that problem in NSW Yet? However in that case, if the grid is 100% renewable at that time and can’t take any more, there is no longer an environmental benefit to export (at that time) but an economic benefit in having the battery.

- there is no benefit to the ‘neighbour’ from My excess solar if the grid is producing 100% renewables for any period of time, which will start happening more often based on your excellent monthly data. In that scenario, there is significant environmental benefit in storage.

Again that is an unusual scenario in most of the country at present. Ultimately, when the grid is 100% renewable all the time, it will make no environmental difference whether you keep excess solar in a battery, export it, or open-circuit your panels to do nothing. The battery then will be a purely economic tool, all the time.

 

[paulp]

Well we certainly don’t have that problem in NSW Yet? However in that case, if the grid is 100% renewable at that time and can’t take any more, there is no longer an environmental benefit to export (at that time) but an economic benefit in having the battery.



Again that is an unusual scenario in most of the country at present. Ultimately, when the grid is 100% renewable all the time, it will make no environmental difference whether you keep excess solar in a battery, export it, or open-circuit your panels to do nothing. The battery then will be a purely economic tool, all the time.

But to get to that point isnt a sudden moment where everyone gets solar and storage. Its a gradual buildup which has to be started by early adopters and at some point a crossover occurs and its mainstream. SA probably isn’t many years from the storage crossover, although the interconnector potentially complicates it as our excess renewables can go to you in nsw.
We cannot all wait for the grid to be 100% renewable before acting, and that action may not always be the best thing financially In the short term. But any house selling agent in SA will tell you a house with solar sells for more and a house with solar and storage sells for more again. So when the house is sold, maybe the capital comes back and the battery was indeed incredibly viable. I’m certainly seeing this with energy efficient commercial buildings where environmental credentials pay back and with interest!

 

[cafz]

Agree re gas, thats why I think gas hot water in SA is quite efficient if being produced at night compared to using gas fired electricity to produce hot water at night (Or when rooftop solar isn’t 100%).

It's very rare for gas to be a majority of the electricity mix in SA, even at night. There's always some gas running for system strength reasons, but in the usual case wind covers most of the night demand.

Timed off-peak HWS in SA should be moved to the day solar peak. Currently it's now adding demand at almost exactly the wrong time.

 

[atj777]

Well, I admire the motivation, as it was similar to mine, but a battery merely timeshifts solar. If you don’t have a battery, your excess solar is exported to the grid, which has the effect of making the grid cleaner since it displaces fossil generation.

So all the battery is doing is changing who gets to use your excess solar. Is it primarily you (battery), or is it your neighbours (no battery)? In environmental terms, who uses the excess solar is irrelevant. It is therefore your solar panels that are creating the environmental benefit, not the battery.

Yes and no.

So, I export power to the grid which makes it available to my neighbour. The thing is they get zero benefit from that because they will still be paying the exact same rate their power company will charge them at that time of day. I'm benefiting no-one by exporting at that time of day.

Exporting excess solar to the grid is not necessarily a good thing and it isn't going to displace fossil fuel based generation in any real way.

Basically, if I didn't have a battery, I'd be exporting any solar I'm generating but not consuming. This will be replicated across every house with solar (and no battery). This means that in the middle of the day where domestic solar generation is high but domestic consumption is low, there is an excess of power on the grid. We have already seen the effects of this with lower and lower FITs. In some jurisdictions the FIT drops to zero at peak production times and some even get charged for exporting to the grid. This is becoming quite the problem.

Now, later in the day domestic solar production will drop but household consumption will increase (people coming home from work, cooking dinner, etc.) and there will be a great need for power. It is these peak period where fossil fuel based generation gets used the most. If they are gas powered stations there is some flexibility to increase production to meet demand but with coal based production there is little scope so those plants run 24x7.

You nailed it when you said that a battery time shifts solar. This is exactly the point, except you make it sound like a bad thing when in fact it is a good thing.

If I store the solar I'm not using, I'm providing two main benefits:
1) I'm not putting power into the grid at a time it is not needed
2) I can use that stored power from my battery instead of the grid, lowering the demand on the grid when the demand is at its highest (at least from a domestic perspective).

At some times of the year, I'm not using any power* from the grid from a net perspective. That's less power that needs to be generated. At other times of the year I may need to pull some power from the grid but I am able to do this when the demand is low and it is power that would go to waste anyway. So, overall, I'm using less power from the grid at any particular time, and what power I do take from the grid, I'm taking when there is low demand.

What I'm doing in my house alone is not going to make much difference, but could you imagine if every house had solar and batteries? That's where we should be heading. It is not the only solution, but it would make a huge difference and would reduce the reliance on fossil fuel based generation for domestic use.

Perhaps a better solution would be community based storage but I can't see that happening with the current infrastructure.

* I still have a HWS on controlled load grid power but that is pulling power from the grid when demand is low and when it dies I'll replace it with a heat pump and power it from the powerwall.

 

[Vostok]

It's very rare for gas to be a majority of the electricity mix in SA, even at night. There's always some gas running for system strength reasons, but in the usual case wind covers most of the night demand.

Last I looked (more than a year ago now) SA was still 56% renewable on average at times when solar production was zero. Pretty impressive, I thought.

SA looks to have the mix about right - double the amount of wind power compared to solar. VIC is next best with a growing wind component matching or exceeding solar, with WA not far behind. QLD has the worst mix - its renewables are dominated way too much by solar, leading to a highly variable renewable contribution that swings from 0% to 50%. It’s not like it never gets windy in QLD! What are they doing up there?

 

[Vostok]

Exporting excess solar to the grid is not necessarily a good thing and it isn't going to displace fossil fuel based generation in any real way.

Millions of rooftop solar arrays each exporting some power to the grid adds up. Last month 11% of all of Australia’s electricity was generated by rooftop solar. A significant fraction of that would have been exported to the grid.

Power grids are zero-sum games. The total amount of energy generated has to be matched at all times to energy demand. So any clean energy injected into the grid is going to displace some fossil generation. Until of course the grid is 100% renewable.

 

[paulp]

Millions of rooftop solar arrays each exporting some power to the grid adds up. Last month 11% of all of Australia’s electricity was generated by rooftop solar. A significant fraction of that would have been exported to the grid.

Power grids are zero-sum games. The total amount of energy generated has to be matched at all times to energy demand. So any clean energy injected into the grid is going to displace some fossil generation. Until of course the grid is 100% renewable.

Equally any new electrical equipment is going to cause more fossil fuel generation unless more renewable is added with it

 

[cafz]

Power grids are zero-sum games. The total amount of energy generated has to be matched at all times to energy demand. So any clean energy injected into the grid is going to displace some fossil generation.

It depends a bit on where you are, though. Frequently in SA with the interconnector constrained and renewable generation high, you'd just be displacing large-scale renewables. Tassie you'd be displacing some hydro which is fine, it just saves the energy for later. NSW and VIC you'd be displacing fossil generation. QLD is more complicated due to transmission constraints.

 

[atj777]

Power grids are zero-sum games. The total amount of energy generated has to be matched at all times to energy demand. So any clean energy injected into the grid is going to displace some fossil generation. Until of course the grid is 100% renewable.

Not at that level. Coal-fired power stations can't be turned on and off. Gas powered stations can be more demand driven. NSW is around 80% coal (at least was in 2018/19) and coal-fired power stations run 24x7 with little scope for changing their output as demand changes. They certainly can't lower production when a few roof-top solar system export to the grid.

WA is now joining SA in switching off solar when supply is higher than demand:

As household solar stresses the grid, WA and South Australia will have the power to turn it off

Authorities are moving to gain more control over rooftop solar panels amid a ballooning number of installations that are threatening to overload the grid at certain times.

www.abc.net.au

 

[paulp]

Not at that level. Coal-fired power stations can't be turned on and off. Gas powered stations can be more demand driven. NSW is around 80% coal (at least was in 2018/19) and coal-fired power stations run 24x7 with little scope for changing their output as demand changes. They certainly can't lower production when a few roof-top solar system export to the grid.

WA is now joining SA in switching off solar when supply is higher than demand:

As household solar stresses the grid, WA and South Australia will have the power to turn it off

Authorities are moving to gain more control over rooftop solar panels amid a ballooning number of installations that are threatening to overload the grid at certain times.

www.abc.net.au

The SA switchoff only applies to new systems installed after (for memory) 1 july last year. It does not apply to systems installed before that. Applies to upgrades and size increases too, so a lot of people installing batteries will get caught with it as well.

 

[atj777]

The SA switchoff only applies to new systems installed after (for memory) 1 july last year. It does not apply to systems installed before that. Applies to upgrades and size increases too, so a lot of people installing batteries will get caught with it as well.

Yep. But my point still stands that while solar rooftop will help with the shift away from fossil fuel based generation, it also introduces problems because the generation typically occurs when demand is low resulting in more power on the grid than is being used.

That's where batteries come in. They allow the solar which is being generated while demand is low to be used later when demand is high. This evens out the demand on the grid and is much better for shifting away from fossil fuel based generation.

 

[paulp]

Yep. But my point still stands that while solar rooftop will help with the shift away from fossil fuel based generation, it also introduces problems because the generation typically occurs when demand is low resulting in more power on the grid than is being used.

That's where batteries come in. They allow the solar which is being generated while demand is low to be used later when demand is high. This evens out the demand on the grid and is much better for shifting away from fossil fuel based generation.

Completely agree. I dont really export much anymore with the batteries, so that means someone else can leave their solar on as I no longer add to the FIT grid load in SA. With the thousands of house batteries added together that is a significant environmental benefit In markets where FIT shedding occurs as it permits more solar generation