As per title, does anyone on here get involved with PV installations, after some advice re G98/99

Not an installer, but I just recently fitted my own 6kw system and had to apply for the G98/G99.

Great! 2 things, I thought anything over4kW required additional paperwork or a different application - is that no longer the case?

What exactly is involved, what's the procedure with the G98/99?

I believe you apply for the G98 from your DNO? What exactly happens then? What gets inspected & by whom? Or is it simply a case of making the installation as per instructions & then just getting a sparky to sign off prior to actually commissioning? Is that when the G99 gets sent in?

Any advice/info much appreciated

You go on your DNO's website and apply there.
The company I purchased my kit from gave me the relevant information to put on the application.
It can take upto 45 working days to complete.
They still charge for anything over 4kw as they look at weather your local layout can cope with the extra ampage.
It costs anywhere from £350 to £850 before VAT.
It cost me the lowest amount as there was no extra strengthening needed as I live in a bit of a rabbit warren and plenty of households to use up my surplus energy
Hope this helps
If you need anything else just ask.

Brad

So if we're just looking at the basic 3.6kW Inverter & not exporting more than that, it's just a G98 application & a sparky sign off, is that it? & no charges?

Sounds far too easy, I'm obviously missing something!

Is MCS not a concern for you guys? Everywhere I've seen that pays for exported energy has required MCS certification, which can't be retroactively applied, they tell me.

quote:

---

Originally posted by coyoteboy
Is MCS not a concern for you guys? Everywhere I've seen that pays for exported energy has required MCS certification, which can't be retroactively applied, they tell me.

---

quote:

---

Originally posted by coyoteboy
Is MCS not a concern for you guys? Everywhere I've seen that pays for exported energy has required MCS certification, which can't be retroactively applied, they tell me.

---

quote:

---

Originally posted by russbost
So if we're just looking at the basic 3.6kW Inverter & not exporting more than that, it's just a G98 application & a sparky sign off, is that it? & no charges?

Sounds far too easy, I'm obviously missing something!

---

quote:

---

Originally posted by roadrunner

quote:

---

Originally posted by russbost
So if we're just looking at the basic 3.6kW Inverter & not exporting more than that, it's just a G98 application & a sparky sign off, is that it? & no charges?

Sounds far too easy, I'm obviously missing something!

---

If it's just a basic 3.6kw, then yes, they don't charge. But you still have to let them know.

---

quote:

---

Originally posted by russbost

quote:

---

Originally posted by roadrunner

quote:

---

Originally posted by russbost
So if we're just looking at the basic 3.6kW Inverter & not exporting more than that, it's just a G98 application & a sparky sign off, is that it? & no charges?

Sounds far too easy, I'm obviously missing something!

---

If it's just a basic 3.6kw, then yes, they don't charge. But you still have to let them know.

---

& you install the system first & actually have it working & then notify with the G98, is that correct?

Is there also something about the inverter being G98 certified or something, I seem to remember reading that that was the case?

---

quote:

---

Originally posted by russbost

quote:

---

Originally posted by coyoteboy
Is MCS not a concern for you guys? Everywhere I've seen that pays for exported energy has required MCS certification, which can't be retroactively applied, they tell me.

---

Doing my utmost to avoid MCS, I already have an old MCS installation from back in 2011, don't ask me how much they pay me per unit it's embarrassingly high!

This is a cheapy install for/with a friend who, along with myself has bought a load of Second Hand panels (should anyone want some I have access to more, tho' shipping is expensive unless ordering in quantity)

He has no intention of getting paid for sending power back to the grid as he will use nearly all himself except in the height of summer & if you want to go the battery route (which I've done myself in addition to the original 4kW array) then do it off grid, sending them power back simply doesn't pay sufficiently to make it worthwhile unless you can get on a V2G pilot scheme or similar. My last 2 months energy bills (gas & leccy - total) come to about £60 & a sizeable chunk of that is standing charge, I've used no gas as get all hot water heated for free & about the only electric we're using is oven/hob/microwave/kettle, & the EV charge which is 4 hours overnight at 5p/kW everything else is off grid

If you go the MCS route everything has to be new installed to the exact demands & by a MCS installer - in other words, jobs for the boys! You get charged best part of double for the same job.

A friend recently installed an 8kW grid tie, all brand new gear for around £5500 (he did installation himself), I'd guess around £10k thro' an MCS installer - even with prices going thro' the roof, the MCS install is gonna take a VERY long time to pay for itself, if ever

---

"FWIW I think outgoing octopus pay upward of 30p/kwh in peak times, if you can generate it. I'd be tempted to install a battery setup and watch the outgoing prices and only export during those times, if I had the time to faff."

I may be wrong, but have a feeling that that is only available on certain pilot schemes, I think normally Ocyopus nest rate of payback is 8p/kW. As regards faff, I think you'll find that you can control things automatically, but need some hardware installed to do so. Our Ohme EV charger will ONLY charge the car if leccy is below 6p/kW, in other words at my 5p for 4 hours night rate

quote:

---

Originally posted by russbost
"FWIW I think outgoing octopus pay upward of 30p/kwh in peak times, if you can generate it. I'd be tempted to install a battery setup and watch the outgoing prices and only export during those times, if I had the time to faff."

I may be wrong, but have a feeling that that is only available on certain pilot schemes, I think normally Ocyopus nest rate of payback is 8p/kW. As regards faff, I think you'll find that you can control things automatically, but need some hardware installed to do so. Our Ohme EV charger will ONLY charge the car if leccy is below 6p/kW, in other words at my 5p for 4 hours night rate

---

quote:

---

Originally posted by coyoteboy


Their tariff is called outgoing Agile - it seems to be available across the UK, and pays a pretty huge amount during peak hours (like pounds per unit). They do say they require MCS though.

---

I think not being able to have Go and agile outgoing at the same time is entirely intentional. There is (or at least was) an explanation for this on their website. Else you'd just buy using their off-peak and sell at peak using battery storage. I've. They won't let you have it both ways. You have to have agile incoming to have outgoing iirc, or at least you can't have Go.

That's actually the business model of commercial energy storage facilities, and it's the route the companies are likely go in future when people get EVs hooked up more commonly. They probably just want to get a handle on the numbers and practicalities. If that wasn't the route they were going to take, there would be no benefit for customers hooking EVs up to two way ports and EV manufacturers would have no incentive to include duplex chargers, which they're looking into.

[Edited on 3/8/22 by coyoteboy]

I'm not saying it isn't a valid methodology it's just they don't want to give you a subsidised off peak rate then let you sell it back to them at a multiple.

quote:

---

Originally posted by hobbsy
I'm not saying it isn't a valid methodology it's just they don't want to give you a subsidised off peak rate then let you sell it back to them at a multiple.

---

Hi everyone - a bit late to the party but I have some questions

I'm in the final stages of refurbishing a large (10m x 10m) outbuilding next to my house, and plan to fit PV panels to the south face of the roof. I've got about 50 square meters to play with, perhaps a bit less, but plenty for a decent sized (5-6kw) array. The roof is about a 14 degree slope and faces almost exactly due south with no shading whatsoever. Location is west central Scotland.

The roof is a Kingspan 80mm insulated metal roof with timber purlins and a steel portal frame underneath so should be easy enough to attach the panels to. However, I'm keen to do the install myself because I don't want anyone else drilling holes or walking around and dropping tools on my new roof! Those Kingspan panels cost about £50/sqm and I'm hoping they will outlast me!

We live in a modernised cottage with oil fired heating, log burner and 100A of electricity. We use about 9600 kWh a year since we also have an electric vehicle (BMW i3) which my wife uses for commuting. I work from home full time as an IT consultant so we have a fairly large base load. We are currently with Octopus and were on Octopus Go until April when we were switched to the variable tariff which is about 29p (08:30-01:30) and 21p (01:30-08:30).

Our aim is to become as self sufficient as possible by virtue of PV panels and battery storage, ideally batteries which can run off grid in the event of a power outage which does happen here as we are out in the sticks with an 11kv transformer on a pole outside the house. I don't really care much about export to the grid since we can easily consume everything we generate if we have sufficient battery storage. My thoughts are to store as much as we can by day, use whatever we need in the evening and dump the rest into the EV, topping up from the grid as needed.

So @roadrunner, I'd be very interested to hear which company you bought your kit from and any lessons you learned during that process. I'm pretty competent with electrics so I plan to do as much of the work myself as possible but will of course get sparky sign off if necessary and register with the DNO.

I'd like a fairly "smart" inverter which can provide detailed info on generation and which can accommodate battery storage and EV charging etc. ie. I want to be able to control the energy generation and consumption to optimise it. Recommendations welcome on which inverter to go for.

In general, any words of advice would be very welcome.

Thanks.

Hi Craig

Curious why you didn't choose to continue on whatever Go tariff was offered the time? Unless you're unable to shift usage. Around that time I think they were offering 30p/7.5p?

quote:

---

Originally posted by hobbsy
Hi Craig

Curious why you didn't choose to continue on whatever Go tariff was offered the time? Unless you're unable to shift usage. Around that time I think they were offering 30p/7.5p?

---

Your Go would have been fixed for a year at the rate at the time though right?

Also Go Faster gives you a choice of start times. I have 5hrs from 2030hrs so use that to put on appliances. if you're looking at battery storage then surely a cheaper off peak rate at the expense of a marginally higher peak rate is the way to go?

Still think octopus are awesome, if you can afford a battery system then the off-peak rates with Go I think are market leading unless anyone else knows of better? If thinking of changing then if you use my referral we both get £50

https://share.octopus.energy/sage-queen-253



[Edited on 24/8/22 by hobbsy]

Hi,

I wasn't aware that start times could be chosen - I was only given the 4 hour 00:30 to 04:30 Go window, which to be honest works well for us because we don't have to worry about overloading the main 100A fuse with any combinations of 32A EV, 40A electric shower or 64A range cooker. I think the tariffs available vary by region so perhaps in my KA24 postcode there is only one low cost window, I don't know. I'll certainly ask next time I talk to Octopus.

I was very interested in Intelligent Octopus as it allows a 6 hour window, and I do have a Wallbox Pulsar Plus charger which they say is "coming soon" as a supported device for Octopus, but it's been coming soon for ages now.

If I did go ahead and buy a battery system then for sure I would look at smart tariffs again because that would allow me to charge up the battery during whatever low cost window I was given (or chose) at the same time as charging the EV, and then use the battery to cover the base load of the house even in the absence of solar panels. I'm currently looking at Pylon Tech battery systems which are modular and would allow a lower cost entry point to allow me to shift my base load to the 7.5p window and then scale up the batteries once I have a solar array installed to maximise the solar power and minimise or eliminate exporting to the grid.

Anyway, we should find out in a couple of days what the next "price cap" will be and I expect that will trigger notifications from energy companies as to what the variable tariffs will increase to. We also have a new PM coming in to office soon as well and I fully expect (surely to god!) that they will announce a package of measures to address the cost of energy/living which might also be a factor in deciding which way to go. There is also this national grid initiative to reward people who can shift their grid loads at certain times of day so that might also suggest a battery solution is the way to go in the short term at least. I actually participated in a scheme with Octopus earlier this year where they would announce 48 hours in advance a 2 hour window where they wanted you to increase your consumption, and would pay you if you met certain goals. I made about £30 out of 5 or 6 such events just by rescheduling EV charging to those period so if that is how the national grid system is expected to work then great!

Let's see what the next week or two brings but I'm definitely leaning towards buying a battery system if that will allow me to make the smart tariffs work decisively in my favour.

@hobbsy,

Thanks for the heads-up on Go Faster, I have now switched on to that using the 5H from 21:30hrs option. The 20:30hrs option is no longer available as far as I can tell. I'm already a customer so couldn't use your referral link.

So yeah, with retrospect it would have been better to sign up back in April for Go (Faster) but I wasn't seriously considering battery storage at that point. Given that it looks as if electricity prices are going to be high for a while and might never return to "normal" (whatever that was!) I think I'll go ahead and invest in battery storage. I got 40.13p peak and 8.25p off-peak compared to 30.83 and 8.25 which I could have had back in April. On the plus side the tariff is fixed for 12 months from now.

Here is my plan:

Buy a DIY installation kit including the following:
Victron Multiplus-II 5000va inverter/charger
Pylontech US5000 batteries X2 (9.6kWh total of which 95% usable) - will add a third battery later along with solar
Various other mandatory and optional bits in the kit.

Total cost is just over £6k including VAT with an break even point of under 6 years with batteries alone at current energy prices but prices are expected to rise so payback period should compress a bit more. Also, with this system I can add as many DC coupled solar panels as I want without requiring any further DNO approval and without any further inverters. All I need is a DC-DC solar charge controller plus the solar panels and bracketry/wiring. The charge controller is about £350.

Since it's a 5kva system it will need G99 DNO approval but since I don't plan to export any energy back to the grid, even if they impose an export limit, the inverter can enforce that no problem as it has a main incomer power meter or CT clamp. Once I have solar panels then any excess energy can be dumped into the EV.

Not pulled the trigger yet but very likely to go ahead. Will let you know what happens.