DNO applications

[Alan Ambrose]

I’m tempted to use Spirit Energy’s £150 DNO application. We are going ‘max-PV’ to try and get self-sufficient power into the shoulder seasons. Is there a sense that you need to tread lightly with the DNO and finesse your application to get closest to what you want - or just go for it and see what they say? Our DNO is UKPN, we have single phase supply, and we want oodles of panels to support shoulder seasons use. House is PH-like but not particularly low energy because of the geometry.

[torre]

We're only just into G99 but my impression from our installer was that the DNO set an export limit rather than just saying no.

[Alan Ambrose]

I’ve heard that some DNOs also want to restrict the size of your array / inverter output etc.

[JohnMo]

Are you having a battery also, if so you need a strategy of what you are doing, as big is better to a point. You maybe better over clocking the inverter with loads of panels, so you have max output for longer periods during a day, and get battery charging as well as max exports.  Lots of ways to do this even with a G98 limitation.

[Dillsue]

6 hours ago, Alan Ambrose said:

I’ve heard that some DNOs also want to restrict the size of your array / inverter output etc.

The inverter is what connects to the grid so DNOs would want to and do regulate inverters and any generator connected to their system.

 

Where have you heard DNOs are interested in panel capacity??

[RobLe]

Our dno is ukpn.  We were relatively early in our area to add solar, 4kWp fit ages ago, + 4kWp V2g in 2020.  They haggled the V2G from 6kWp down to 4, giving a total of 8kWp.  Since then others around were granted 5kWp total.  We swapped out our V2G for more solar a couple of years ago - they were happy to allow us 4kWp (+4kWp fit), matching the removed v2g.  I was impressed by them, they didn’t just say ‘no’, but tried to accommodate.  And the process is free, unusual this day and age.

Nb:  our ‘extra solar’ is a 3.6kWp sunsynk hybrid inverter+16kWh battery+10kWp of panels just for it - it charges the batts while exporting as well.  Ukpn didn’t care about the battery nor how many panels, just the inverter.

[Dillsue]

56 minutes ago, RobLe said:

 Ukpn didn’t care about the battery nor how many panels, just the inverter.

That's my understanding of how the DNOs operate. Our second system, sat in parallel to an older FIT system, had 8.5kw of panels but SPEN were only interested in the additional inverters rating that was much lower than the panels rating.

[Alan Ambrose]

I find this guy a bit dull, but e.g. (below) - he talks a bit about the export & inverter limits and how this varies with DNO and system etc.

 

https://www.youtube.com/watch?v=Bvpl9pvg8zk

 

>>> Where have you heard DNOs are interested in panel capacity??

 

Good point - I was extrapolating this from typical mppt clipping limits and no of mppts per inverter. e.g. Sig single phase hybrid has 2 mppts and max voltage & current limits giving roughly 46% PV panel over-capacity / clipping limit (depending on size of inverter). So, a limit on inverter size seems to result in an effective limit on the number of panels.

 

 

A subsidiary question - what significance does the installer nomination have on the DMO application? i.e. can you use one installer to do the DNO application and another later to do the later installation. i.e. is the Spirit Energy offer a way of blocking in installs?

 

 

 

[Dillsue]

5 hours ago, Alan Ambrose said:

A subsidiary question - what significance does the installer nomination have on the DMO application? i.e. can you use one installer to do the DNO application and another later to do the later installation. i.e. is the Spirit Energy offer a way of blocking in installs?

Anyone can put a G99 application in...you, designer, installer.

[Dillsue]

5 hours ago, Alan Ambrose said:

Good point - I was extrapolating this from typical mppt clipping limits and no of mppts per inverter. e.g. Sig single phase hybrid has 2 mppts and max voltage & current limits giving roughly 46% PV panel over-capacity / clipping limit (depending on size of inverter). So, a limit on inverter size seems to result in an effective limit on the number of panels.

I think there's lots of inverters that allow 100% over sizing of the DC input compared to the inverter rating....our Solaredge certainly does. If you're looking to max out year round generation then maybe look for inverters that will allow more than 46% oversizing??

Edited 3 hours ago by Dillsue

[MikeSharp01]

6 hours ago, Alan Ambrose said:

A subsidiary question - what significance does the installer nomination have on the DMO application? i.e. can you use one installer to do the DNO application and another later to do the later installation. i.e. is the Spirit Energy offer a way of blocking in installs?

For UKPN you can do it all yourself - we are on single phase, applied for an account, used the web form and off it went we got 7kW peak output set at the inverter with no haggling or anything from UKPN.