The largest system I've seen!

Heedtheadvice

Not pedantic at all Martyn. I am all for clarity and posting things not to confused.

Referred to for example "I don't believe the system has hit 22kWh peak generation yet (which is what DNO's approve)" That statement can confuse readers as it should be kWp power for solar generation (kilowatts peak), leading to power that is the maximum that will be exported ( kW ) as limited by an inverter .....or for a Storage System ( e.g. a battery ) the amount  of energy stored and this is often in kilowatt hours.

Let's not confuse by either being incorrect or mixing fact and opinion.

Correct me by all means or get more clarification on posts as this helps all who read the threads!

Martyn1981

Good points. Not 100% certain, but I don't think the DNO's have ever limited a system by PV size (kWp rating). Instead by inverter/export limit of kW rating.

But ...... something is nagging away at me, from reading my DNO's rules back in 2012, when researching my WNW system. Got a feeling I recall the website saying a system of 3.68kWp or less was permitted for notification after install, regardless of inverter size. Also I think they may have had a seperate rating for systems using micro-inverters, which may have been sum of inverters or sum of panels, I can't remember.  Chatting to the guys in the DNO, they explained that they were learning as they went, just like me, fun times. Then the system changed and was clarfied.

Talk about blast from the past.


PS - Couple of years ago, my sister got a 10.3kWp system installed, but after 3phase had been approved and installed. I was impressed that the DNO, aware of her plans to get PV, advised in the confirmation of 3phase upgrade, that she could have up to 11.04kW of export without prior notification - she actually has an 8kW inverter.

Screwdriva

Martyn1981 said:

Not 100% certain, but I don't think the DNO's have ever limited a system by PV size (kWp rating). Instead by inverter/export limit of kW rating.

This is correct. 

Back to the installation, the homeowner just confirmed his March bill is down to £500 (from >£3000 in Feb '25) 

MeteredOut

Screwdriva said:

Martyn1981 said:

Not 100% certain, but I don't think the DNO's have ever limited a system by PV size (kWp rating). Instead by inverter/export limit of kW rating.

This is correct. 

Back to the installation, the homeowner just confirmed his March bill is down to £500 (from >£3000 in Feb '25) 

You said up-thread £28K for install. If that kind of monthly saving hold, even for 6 months of the year, that's a pretty impressive ROI!

Out of interest, what was the estimated ROI timeframe prior to installation.

Screwdriva

MeteredOut said:

You said up-thread £28K for install. If that kind of monthly saving hold, even for 6 months of the year, that's a pretty impressive ROI!

Out of interest, what was the estimated ROI timeframe prior to installation.

Agreed. 

This system cost £28K installed. In this case, given the size of the installation, I had shared between 4-5 years (20-25% ROI). I always try to be conservative & had no idea his first month's generation would be so strong. The owner has since shared he expects a 3 year timeframe for payback based on what he has seen. 

Heedtheadvice

Yes @Screwdriva that is an impressive first month, and a big money saving! 

I think many of us have been really pleased with this March. Just checked my own figures. From a 4KWp panel system, predicted 3600kWh annually has been up to about 3800kWh. March has been approx 358kWh and that would give ( if the same for all months ) circa 4300kWh.....I guess that would be very optimistic unfortunately.

Screwdriva

Now expanded to 55 panels + a 3rd PW3. Peak generation was 21kWh pre- expansion so we will see what the DNO approves via a revised G99 application. 

The homeowner will be one of the first (if not the first) to receive Tesla’s “Gateway 3” when it releases later this year. 

NedS

Do you have any news on the Gateway 3, and what benefits it may bring over version 2?

Screwdriva

NedS said:

Do you have any news on the Gateway 3, and what benefits it may bring over version 2?

Other than "coming in a few months", not much to share outside of what is known in the public domain. They are trying to increase software/ reduce hardware to allow for seamless 3 phase compatibility. Knowing Tesla Solar, they won't rush it to market till it is ready. 

NedS

If you like large systems, take a look at this video (19 PWs/expansion packs):

https://www.youtube.com/watch?v=Tk8th6LphJU