Solar installation question

@frazer2022

There's loads of info online, especially YouTube for solar panels installation.

Last time I was there, Praktiker has a bunch of solar stuff, with inexpensive panels plus inverters and storage.

I reckon the default option is an off-grid installation, but you'll need a proper switching box to isolate the mains and switch you to solar only. In order to do this, I'm pretty sure you'll need an inverter and a large battery pack (or combined unit).

If your consumption is much more than your solar installation, then I'd imagine it's a lot easier if you spend a bit more for a grid-connected smart/hybrid inverter so that it feeds in solar and/or mains to your house as needed. I'd guess such a device could also feed it back into the grid if you have excess generation but I don't know how to do this (or if Bulgaria allows/encourages it). With a hybrid system you don't need batteries, but it's a bit more flexible if you install some storage, so you can function even if there's a power cut.

The extra cost of a hybrid inverter with a bit of extra capacity (e.g. 6kW or 8kW) seems a sensible investment as you can simply add more panels (and battery storage) in the future.  A Huawei 6kW grid inverter is about a grand, for example, and a 10kW battery pack might be a couple of grand. 600W panels around 100 euros each.

Requirements have been eased quite a bit in the past few years but you'll still have to jump through a bunch of hoops unless your property is completely off-grid. The municipality (ie adminstrative centre, not the village mayor) will need to be involved,  as will the utility company. An engineer's report on the prospective system is needed, especially covering "anti-islanding" and accidental discharge. I seem to recall a rather bizarre requirement that your system has to turn itself off if the grid goes down, to ensure you don't fry a linesman somewhere - but a pain to have to do just when you need it most (I may be misremembering that bit).

There's also a list of approved inverters, IIRC.

There's basically two types of solar system: grid tied, and off grid.

If you are tied, your system needs the mains voltage to synchronise the frequency of the solar supply, and as Jim says this also needs to isolate from the mains system in an outage. You will have to comply with regulations as there will be a number of interested parties involved in the system. Your surplus would go to the grid, conversely the grid will supply the shortfall in poor weather.

If you don't want to get involved with other agencies then off-grid is probably better, but you need to think more about  the spec. of your system as you don't want an excessive load when you have a weak supply, this is where batteries and load controllers are useful.

I have a grid tied system in the UK that was professionally installed without batteries, but have an immersion heater controller which diverts my surplus generation to hot water.

I don't know where Bulgaria is with plug-in solar. Knowing their love of bureaucracy - not available yet, but this would probably suit your needs. You can buy these kits in Germany that plug into your mains system and ' back-feed' a small supply (about 1.5kw) into your system to reduce bills. These are very popular in flats and rented properties.

They are not designed to meet all your power requirements, just to meet the basic base load of a small property. I.e. running the fridge, freezer, and a TV.

Unless you are an electrician, I would get help from an expert installer. It was in the news in Austria that there has been an increase in house fires due to panels being fitted wrongly by home users, making the insurance void.

I don't know where Bulgaria is with plug-in solar. Knowing their love of bureaucracy - not available yet, but this would probably suit your needs. You can buy these kits in Germany that plug into your mains system and ' back-feed' a small supply (about 1.5kw) into your system to reduce bills. These are very popular in flats and rented properties.
They are not designed to meet all your power requirements, just to meet the basic base load of a small property. I.e. running the fridge, freezer, and a TV. - @porridgeandprunes

Here you are > https://sunriseproject.hfh.bg/en/2023/0 … et-part-1/