Growatt inverter, and other solar related queries.

VoucherMan

I'll try my luck here before looking for a more specialised forum.

Brief background: a (non-profit, volunteer run) community organisation where I help, has acquired a building with some solar panels, and a Growatt inverter. I've been tasked with finding out how to make best use of them, and I'm completely clueless. (except for odd bits picked up via Google)

I think the panels could be up to 10 years old. Today was fairly cloudy, and they generated about 10kWh. (I've started monitoring to get a better idea of their usual output)

Electricity usage for the business is quite low. It's generally used only 2 days a week. Main usage is a fridge, heating water, and the odd power tool. During winter there'll also be electric heating. Annual usage is typically under 1000 kWh.

Based on that (I can add more if it helps) can anyone more knowledgable suggest what would likely be the most cost effective way to use them? (battery, SEG tariff, none of the above)

My other query, for now, is about the inverter (Growatt 3600MTL-S -online pdf manual found here) 

 As a (potential) solar user, do I even need to know anything about the inverter? It has a green light to say it's working okay, and there's a meter next to it that shows the power generated.

I've found I can view a variety of information by knocking the casing of the inverter, though if it's possible to change anything, I've not worked out how. I had hoped to correct the date & time reading, but don't know if it's possible.

QrizB

VoucherMan said:

Brief background: a (non-profit, volunteer run) community organisation where I help, has acquired a building with some solar panels, and a Growatt inverter.

Acquired - is that bought, leased, been given, something else?

The conditions around your use of the building are likely to affect what you can do with the PV system.

VoucherMan said:

I think the panels could be up to 10 years old.

If they were installed before 2019, they might be receiving a Feed In Tariff (FIT). this could be worth a four figure sum annually to the beneficial owner, but that owner might not be you.

Doing anything to the PV system that compromises the FIT payments could leave you liable to compensate the beneficial owner.

VoucherMan said:

Based on that (I can add more if it helps) can anyone more knowledgable suggest what would likely be the most cost effective way to use them? (battery, SEG tariff, none of the above)

If they have an associated FIT, the FIT is made up of a generation payment plus an export payment. FIT export payments are relatively low and can be bettered by several suppliers metered export tariffs. If you own the FIT and are entitled to change to metered export, this could be worth doing.

If there's no FIT, being paid for export is the obvious choice.

Additing a battery is a big investment with mulit-year payback. There are also wrinkles when adding a battery to a FIT system. Whether your non-profit wants to invest money in something that won't turn a profit for 5-10 years (if ever) is a decision for the members.

VoucherMan said:

My other query, for now, is about the inverter (Growatt 3600MTL-S -online pdf manual found here) 

 As a (potential) solar user, do I even need to know anything about the inverter? It has a green light to say it's working okay, and there's a meter next to it that shows the power generated.

Leave it alone to do its thing. You might want to check that the green light stays on and that the generation meter keeps increasing (maybe even take periodic readings and chart them on a spreadsheet for your own interest).

Edit: autocorrect inserted a grocer's apostrophe!

debitcardmayhem

You will need to check the supply meter to see if it is measuring export too

VoucherMan

QrizB said:

Acquired - is that bought, leased, been given, something else?

The conditions around your use of the building are likely to affect what you can do with the PV system.

Thanks for replying. Sorry, I don't visit that often these days, hence the delay.

Inherited is probably a better word. The site in question is a community run allotment/garden. After the previous team gave up a few years ago, the current owners took over.

I think much of the design, including buildings, with attached solar panels, date from around 2012, courtesy of a National Lottery grant. (whoops, that'll make them 13 years old!)
To my knowledge the inverter was replaced a couple of years ago, after a solar engineer was called in to look at the system, and he said the old inverter wasn't working. The replacement was an old one had had laying around, and he swapped them FOC. We'd tried to contact the original installers, but I think they were taken over at some point, and the new company wasn't interested.

After discussing the panels, and having a read of https://www.businessenergydeals.co.uk/blog/smart-export-guarantee/ , it was decided that it's probably not worth the hassle anyway. Personally, I don't think the current owners will still be running it in 10 years, so probably not worth considering 'long term' investments.

At least I got the right idea printing off a log sheet, so I can keep checking the inverter readings for my entertainment. I'm still waiting for a day of strong sunshine so I can see how much more power is generated.

paul991

who owns the building ,council?

VoucherMan

paul991 said:

who owns the building ,council?

It's 'owned' by the current tenants. That said, the buildings with the solar panels are just converted shipping containers.

QrizB

VoucherMan said:

I think much of the design, including buildings, with attached solar panels, date from around 2012, courtesy of a National Lottery grant. (whoops, that'll make them 13 years old!)

In which case, it's more likely than not that they're covered by a FIT, with payments possibly overdue.

It might be worth submitting an ownership query to Ofgem:

https://www.ofgem.gov.uk/scheme-contacts-fit

VoucherMan

QrizB said:

In which case, it's more likely than not that they're covered by a FIT, with payments possibly overdue.

It might be worth submitting an ownership query to Ofgem:

Much as I'm tempted to email them myself, I suspect the ID issue could be problematic, so probably best if I talk to the bill payer first. (sod it, I've emailed them anyway)

This could become interesting entertaining if the previous owner is still the beneficiary. The current & previous owners do not get on. If current owner were to realise that they'd repaired a broken system, thereby generating income for the previous owner, I can see the system becoming 'broken' again quite quickly.