Starting from scratch, new design for grid-tied PV system, 8.5kW panels, 14.5kWh storage, 8kW inverter. G99 Form

[Smallholder]

12 minutes ago, TonyT said:

Get over to the Camelot forum, Nowty and Joeboy have the systems you are looking at and Nowty is very clued up on all the G99,G100 etc 

 

Absolutely brilliant, many thanks!

[SteamyTea]

26 minutes ago, Smallholder said:

Though our daily lifestyle is so unpredictable that I'm not sure I would get a lot from the data?

It probably isn't.  We are all individuals, just like everyone else.

26 minutes ago, Smallholder said:

I'm just wondering what changes I might make to the suggested system

Not really about designing what is in effect and off grid system, what I think you are trying to do is mimic the reliability and availability of the National Grid.

That is probably not the best way to look at the problem.

Demand management is the cheapest and most effective option.

[joth]

7 minutes ago, Smallholder said:

So in summer I'd not be able to export anywhere near as much as I'd need to.

Can you clarify what you mean by "needing" to be able to export so much - where does the requirement come from? (it's not technical or financial, so... ecological? which is fine. just confirming  ) 

 

[Smallholder]

5 minutes ago, SteamyTea said:

It probably isn't.  We are all individuals, just like everyone else.

Not really about designing what is in effect and off grid system, what I think you are trying to do is mimic the reliability and availability of the National Grid.

That is probably not the best way to look at the problem.

Demand management is the cheapest and most effective option.

 

I agree we are all kind of similar, as humans. But both my wife and I are self-employed, and we do not have any regular routine. Some days I am at home 23 hours out of 24, other times I'm not at home at all for a few days straight.
There's also the point that our current consumption patterns are likely quite different to what the will be when we are generating our own power. Having been off grid at the farm for years, we have learned how to shift demand, but there is not such a great need for this at home beyond charging the EV's at night.

It seems mad to design a system around a pattern that will change drastically.

[Smallholder]

10 minutes ago, joth said:

Can you clarify what you mean by "needing" to be able to export so much - where does the requirement come from? (it's not technical or financial, so... ecological? which is fine. just confirming  ) 

 

 

I was coming from the angle of trying to get paid to export, but if that's a no go (if we can't get MCS), then it would still be good from an environmental perspective.

 

Even without getting any payment for feeding in, I'd be prepared to foot some additional expense in order to maximise what I feed in to the grid. Within reason.

[Smallholder]

 

VAT etc

Am I missing a trick here, in terms of VAT?

I understand that all kit involved in the new installation of a PV system is VAT zero rated, including batteries? So if I buy all the stuff myself, at a cost of say (very rough ballpark!) £15k inc vat, then I'm paying £2,500 in vat, that could potentially be saved and put towards an MCS registered installer doing the job.

 

Not sure it makes any difference, but I am fortunate to have accounts with a couple of good suppliers that do panels, batteries, inverters etc.

 

I guess there's no harm in getting a quote from an installer, and seeing how it compares to my equipment costs.

There's also the point that I LOVE doing these jobs myself, and knowing how the kit works, how it went together etc.

 

I wonder, roughly, what the export payments would be each year.

[Marvin]

43 minutes ago, Smallholder said:

 

I wonder, roughly, what the export payments would be each year.

As I understood it if you sell to the grid (So to speak) you have to buy at a higher price? Or is this old hat now?

[Smallholder]

2 minutes ago, Marvin said:

As I understood it if you sell to the grid (So to speak) you have to buy at a higher price? Or is this old hat now?

 

[Marvin]

2 minutes ago, Smallholder said:

 

Thanks for this. Who is this with?

 

I must admit I hate making long term decisions based on short term rates, and we do not have a smart meter and I do not want one.

[Smallholder]

3 minutes ago, Marvin said:

Thanks for this. Who is this with?

 

I must admit I hate making long term decisions based on short term rates, and we do not have a smart meter and I do not want one.

This is the Octopus Flux tariff. As far as I know, there are not many alternatives for export. Though I may be wrong.
You'd definitely need a smart meter.

[joth]

22 hours ago, Smallholder said:

Am I missing a trick here, in terms of VAT?

I understand that all kit involved in the new installation of a PV system is VAT zero rated, including batteries? So if I buy all the stuff myself, at a cost of say (very rough ballpark!) £15k inc vat, then I'm paying £2,500 in vat, that could potentially be saved and put towards an MCS registered installer doing the job.

 

Zero VAT is only on supply+install. If you purchase and diy install then you'll pay full VAT. (Same with ASHP.)

Only trick is to get a friendly installer that lets you do a lot of the grunt work yourself and will give a discount for that.