Solar & Powerwall 2

[old.Osy]

We're putting in a 10Kw system soonish, 8kw Fronius Gen24 to power it. No battery.

Total cost, 8600 GBP, government covers 3500, so pocket cost of approx 5100.

Net metering is a thing, as are credits - we'll see what that does to the bill in time. We'll be selling energy back to the grid, but it's not as straightforward as it may seem, as we run 3-phase, and the inverter can only do 3KW instant per phase, so if I have a bunch of appliances on a single phase drawing more than 3KW instantly, I will be pulling the difference from the grid, even if overall the system produces more than we actually spend.

What that means is I will have to careful balance out the AC units and the other major consumers (dish, wash, dryer, kettle, etc), in order to mitigate the above as much as possible. So that's some re-wiring in the future, potentially.

I specifically wanted Fronius because of the local API and no cloud nonsense (you can go via cloud if you want, but it's opt-in) - I'll plug this into HA (Home Assistant) locally.

Huawei, Growatt, Deye are a few brands which installers push out here, but they're all cloud locked. I hate that.

 

[Scouse]

How come no battery m8? Doesn't that make most sense for overnight power etc?

 

[old.Osy]

How come no battery m8? Doesn't that make most sense for overnight power etc?

With the current battery tech and costs, it really doesn't make sense financially. Besides, our consumption stalls once it's dark out, with some exceptions.

I hope with the energy credits racked during day time to cover the extra pull from the grid, so that it's net.

 

[Embattle]

Indeed as originally stated I didn't expect the battery to make a return on investment due to the cost of the Tesla Powerwall 2 and its installation being nearly £8000, after 4 years and 6 months the battery has done the following:



So if I use the figure of 4.4 MWh and convert that to 4400 kWh then use an average of 20p per kWh to buy that electricity then the total saved is £880.

There are other ways to improve the return, so also as mentioned in one of my previous posts you could fill up the battery with cheaper night rates but a couple of issues arise because I can't use both an export tariff and take advantage of lower night rate tariff to fill the battery. The second issue is you just wouldn't use the cheaper night rates during the summer periods when the battery easily fills. Naturally, the other advantage is it does act as a backup device as well.

The solar survey is on Wednesday for the 2KW extension.

 

[Scouse]

Oof. A 36 year payback on the tesla :/

What's yer current profit against cost for your solar @Embattle ?

 

[Embattle]

Oof. A 36 year payback on the tesla :/

What's yer current profit against cost for your solar @Embattle ?

Well using last year:



Now let's pretend the battery doesn't exist and split its power 50/50 because without the battery we would probably use the solar more wisely in the home.

So the average price per kWh in 2023 was 27p, the average export was 15p.

Home - 0.27x2875 = £776.25
Export - 1260x0.15 = £189

So the total savings last year would probably of been in the region of £965.25 if we never had a battery. The high price of electricity of the last couple of years really boosts savings, but you'll easily cover the cost of solar over the lifetime of panels even with the cost of a replacement inverter.

 

[Deebs]

I am going to have solar installed and more than likely a battery as I have a datacenter's worth of electronics/computers on 24hrs a day. My electric bill is huge so I don't think it would take long to recover the cost but one question, in the event of a power cut/surge (at night) the battery acts quick enough to keep everything running (ala poor mans UPS)??

 

[Embattle]

I am going to have solar installed and more than likely a battery as I have a datacenter's worth of electronics/computers on 24hrs a day. My electric bill is huge so I don't think it would take long to recover the cost but one question, in the event of a power cut/surge (at night) the battery acts quick enough to keep everything running (ala poor mans UPS)??

Most the time yes, but not every time. In essence mine detects wobbles in the grid and switches to the powerwall, although this did cause an issue for me and some other users in North Devon when a company was outputting more than they agreed to the grid which caused excessive noise and 100s of false readings each week.

 

[Embattle]

I think solar panels are a no brainer in my opinion, if you can you should get them installed.

 

[Embattle]

It seems May this year was indeed more cloudy than May last year, even including some good sun over the next two days it'll be over 100kWh down which follows lower amounts in previous months compared to last year.

 

[Embattle]

New recycling method makes solar cells even more environmentally friendly

All the major elements in a solar panel can be reclaimed using less energy.

arstechnica.com

 

[Overdriven]

New recycling method makes solar cells even more environmentally friendly

All the major elements in a solar panel can be reclaimed using less energy.

arstechnica.com

This is the thing I'm interested in as in X years I imagine there'll be a fair bit of electrical waste which'll invalidate a lot of the environmental benefits of solar.

Same with electric batteries.

(Also I'm too poor atm to get solar panels..)

 

[Embattle]

This is the thing I'm interested in as in X years I imagine there'll be a fair bit of electrical waste which'll invalidate a lot of the environmental benefits of solar.

Same with electric batteries.

(Also I'm too poor atm to get solar panels..)

I don't think it will, there are valuable materials in solar panels and they last up to 25 years because all that happens is over time they produce less power.

 

[Embattle]

Interesting video:


View: https://youtu.be/sLyawfMcki4?si=TfUd_f3Eheku5xmF

 

[Embattle]

So the install of the additional solar has started today, hopefully if it all goes to plan it should be finished today.

 

[Embattle]

So all done and working although I did have to pop up a ladder to the loft to seat the data logger properly so I can access it directly. Going to check if the Tesla Powerwall does achieve it's peak input of 5kw tomorrow, see if the output to the grid is still exceeding the 3.7kw limit and hope the smart meter starts to work again.

 

[Embattle]

So another update, now this is just an example of the generation:



A couple of points on the above graph:

1. We've not had a day with full sunshine yet, the above graph shows sun with occasional clouds.
2. That 42.5kWh is still 10kWh better than my previous best pre upgrade.
3. The grid output is still exceeding the 3.7kw allowed thus the inverters are not reducing there generation.

We've been told that at the moment the Tesla PW2 is limited to 3.7kw due to agreement with the DNO, I'm pushing to allow it to go to its peak of 5kw as it is for self use thus can't output to the grid anyway.

On the heating front we are replacing our basic Honeywell heating controls with the Drayton Wiser system including Smart TRVs.

 

[Scouse]

This is the sort of shizzle that I like. But at 42kwh you're producing about 5 times my daily electricity usage at the moment. And when winter comes around - and I'll want it - I'll produce dick.

 

[Embattle]

This is the sort of shizzle that I like. But at 42kwh you're producing about 5 times my daily electricity usage at the moment. And when winter comes around - and I'll want it - I'll produce dick.

Well that isn't shocking in any solar system but even more so in the northern hemisphere, last year the month with the most generation was May at 720.7 kWh (58% Solar, 36% PW2, 6% Grid, 241.2 kWh Export), and the worst was the following December at 56.9 kWh (10% Solar, 2% PW2, 88% Grid, 0 kWh Export). Last year saw the following split for our energy sources 40% Solar, 18% PW2 , 42% Grid and total exports of 647.5 kWh or put another way enough exported energy to power a kettle continuously for nearly 9 days.

 

[Scouse]

Export of 647kwh, about 30 quid?

 

[Embattle]

Current rates £97, but even with the additional panels probably increasing that it is just a nice bonus and not why we have them.

 

[Embattle]

So we've had a Drayton Wiser smart heating kit installed, we might add some Wiser Smart TRVs at some point to give us more control over our heating.

We've also ordered a Myenergi Eddi as well, this product is a solar diverter that reads from a wired CT clamp on your main power supply coming in when you are exporting and then gets the Eddi to divert power to a heating element in the hot water tank, however due to the distance between the two we are going to use a Myenergi Harvi wireless CT clamp.

 

[Embattle]

Installed Eddi & Harvi yesterday and once the battery was full and it started to export the Eddi swung into action, thus it works.

The Wiser Trio IHD arrived today, this is much like a smart meter display but doesn't send the figures to our energy provider which the old one will still do, instead this data feeds into the Wiser app and provides more data. The Wiser smart TRVs are on offer in the Amazon Prime sale so those have now been ordered as well.

 

[Deebs]

Fucking hell, please DM me your address. When the zombies arrive I shall be at yours in a few hours. Not taking any chances. When I get there can we put a sign up with a map on how to get to @Scouse 's house as if they bite him they will die and we all get to be free.

 

[Embattle]

So the guys from Sungift arrived on Friday to install the limiter, thus the export to the grid won't exceed 3.6-3.7kW whereas it had been reaching 5.2kW at times. This is done by using a CT clamp around the main cable inside the Tesla gateway and this is attached to the recently installed string inverter in the loft, reducing its output. Two weeks ago Sungift also sent another form to the local DNO (National Power) with an updated diagram including a request to allow the Tesla PW2 to increase input/output to 5kw from the 3.68kW it is currently set at as it is only for self use.

 

[Embattle]

Can the solar industry keep the lights on?

Global supply glut of panels is hurting producers but also helping installations.

arstechnica.com

 

[Embattle]

View: https://www.youtube.com/watch?v=gkUdfU41iUg

 

[Embattle]

So a few updates:

1. We are changing the tariff to the one mentioned earlier in this post, we get slightly less for our export (8p vs 15p) but get 5 hours of cheaper electricity (8.5p) from 00:30-5:30. This change will enable the EV to charge during this time and I can setup time-based controls on the Tesla Powerwall 2 which means it'll pull energy and fill up for the darker months and we will line up dishwashers, washing machine, etc for this time window as well. On those rare occasions during certain months when our battery might remain full the feed from solar goes House->Battery->Hot Water Diverter->Grid.
2. Our installer has said that our local DNO (National Grid) has confirmed we will be able to increase our Powerwall 2 Input/Output to 5kW rather than the 3.7kW it is currently set at, although they are waiting for the paperwork and then need to send an electrician as well.

 

[old.Osy]

Sun's out now, so that'll be the production for the day (inverter was restarting itself in a loop until 2 pm when i fixed it)

Tomorrow's data should be more "normal"

I know I said we're not going for the battery. But we had a 27 hour blackout a month back, and the wife said she doesn't care how much it costs or about ROI. So now we have a BYD HVM 3 module battery.

 

[old.Osy]

View: https://streamable.com/f2krxf