EDP, our energy provider have been trying to persuade us to install a solar system in our home.
The system that they recommend consists of 8 solar panels amounting to 16 sq mts, on the roof , and with a total output of 3.24 Kw.
Also included is a 5Kwh Battery. Although they admit that the system is not capable to provide all the electricity we require, it is expected to reduce our Grid requirement substantially, with a saving of around 600€ pa. Our current annual bill is around 1200 total pa. The buying back by EDP, of any surplus energy generated by the system would be compensated for, with a 10% discount on any additional Grid energy that we require but for the first 2 yrs only.
Potencia charges and the other addons do not change.
The cost of the system is 10,000€ payable up front or in 60/96 month instalments costing a bit more.
The contract includes 12 yr warranty on the panels and 10 yrs on the battery. Annual cleaning of the panels is included.

Solar systems have reduced in price quite dramatically over the past few years and I noticed that Leroy Merlin have 2 sq mtr panels costing 109€ each so 8 x 109 = 872 plus a battery and installation say another 4k comes to 5k tops ?
So comparatively, the EDP deal looks very expensive.
I,m wondering if anyone has gone for a EDP system, and if so how is it working out ?

Any/ all observations gratefully received !

Absolute waste of money. Only interesting to tree hungers and zeros.
Based on rough cost you provided, it will take 16y before you see any return on investment. You would get better return by putting 10K in stock market for 16y, just saying.
Solar energy would only be viable if they could return on investment in 5y, none of it can do that today.

Double glazing used to be con of the day, things have now moved to solar hype.

Surely, if the system could provide all that you require then it might make some sense, otherwise why bother, especially at that cost level?

Well, my calculations are different; I don't have the numbers in front of me, but PV panels pay for themselves in about 8 years if they're sized for maximum benefit and oriented in an optimum manner (many are not).
That's assuming electric heating (heat pump) and a buffer so most heat can be made in daytime, calculated with Portuguese sunlight and Portuguese electricity prices.
Because I already have bi-horia rate, I can see how much I use in daylight hours. I can also see exactly how much heat I use now, and that is my basis for the numbers.

However, when a battery is added, the numbers don't come out very good. the battery costs more than the power it ever gives you, last time I checked.

So my conclusion was do not invest in the stock market until after you have PV panels on your roof; but there are a lot of variables.

It's very difficult to find someone to advise you, since they all want to sell you the material they like to sell. When I looked at the EDP offer, it was good; but it's even better for EDP. They get your excess power for free (or close to free) and sell it for 20 cents.

Battery prices are dropping like a stone and in addition new solutions are coming which do not require complex installation.

Take a look at HOMEWIZARD which offers a lot of energy monitoring options as well as a new plug-in battery system which can be expanded as required.

I have 16 solar panels on my rooftop terrace. In summer time, my electricity bill is practically zero. November and December and most likely January is a very different story. We've been around 300 per month.

Not sure where you live but it'll take a few years to recover your investment. I genuinely believe it's a waste of money and in 15-20 years you'll just be contributing to landfill when people finally abandon solar

Of course all depends on your local conditions and prices, (I am in NL) . Even so the monitoring App and other accessories are a big help in seeing your actual consumption.
Gas prices went through the roof here and they lowered the electricity tariffs for sending back to the network plus in addition adding extra costs for returning your excess to the grid.
Hence the interest in doing more with the generated power rather than sending it back. One battery is about €1500,- , ROI 3 - 5 years.

Solar panels pay for themselves pretty quickly if you can fully use all you they produce. It is very important to work out your yearly consumption during daylight hours before investing. I live in the North of Portugal and I have a 2.75kW installation that cost 3200 euros to install 3 years ago. I have a control system that charges solar storage heaters with solar production and have hot water and PHEV charging on summed excess power that pretty much minimises what I export to the grid for about 8 or 9 months of the year. I don't have a pool so I do export a fair but during the summer months with only PHEV using solar production up when I am at home. For 2024 my panels produced 3383kW of which I consumed 2682kW which @ 20 cents/kW plus IVA is about 600 euros. I exported 701kW to the grid which works out about 160 euros so having a battery would not be cost effective for me but I will keep an eye on prices. I got a 2000 euro grant from the environmental fund so my installation has already paid for itself. I don't know if grants are still available. I would say solar panels are here to stay and are a great investment.

I think if anybody hasn't looked at solar electric in the last two to three years they'll find as with most developing technology they're very out of touch. As with most improvements there's no golden bullet, its lots of small improvements in all the elements.

Solar panels are now capable of generating greater power and also they can generate it at more oblique angles. The panels I now have are physically the same size as the previous generation but instead of generating 460 watts they generate 595 watts. Each panel has it's own optimiser (which is an extra cost) therefore, if part of the array on a particular string is in the shade it doesn't affect the whole string. Equally, inverters are now much more programmable with the ability to run three and even four strings. The arrangement of the panels is also important, You don't want them all facing in the same direction. I have six facing southeast and 12 facing southwest coupled to a 10kw inverter providing both single and three phase and an expandable battery pack currently with 14kw of storage. The price of batteries have reduced substantially in the last six months and of course if you have a full install (with or without batteries) the IVA is only 6%

The southeast panels give power immediately in the morning (after the batteries have run the villa overnight) and run the villa and the pool pump and give a small initial boost to the batteries. The southwest ones come up to full power from about lunchtime onwards to power the household and the 3 phase pool pump and fully charge the battery pack. Its important to try where possible to equalise the output of the strings and the best way to do this is to make a string where the panels are roughly in the sunshine for the same amount of time.

During the summer in Lagos with five air conditioning units running as well as the pool pump, the fridge freezer and general household electric for cooking etc the electric bill could go as high as 390 euros a month. With this set up its zero. In the winter the air conditioning units heat the villa.

The PV array is fixed to the roof, if it was free standing you can use a double sided PV panel and take advantage of reflected light from below, This would be great in Northern Portugal when you get a covering of frost or snow on the upper surface but the snow/frost on the ground reflects up to the lower surface and the power generated could be directed to either heat the panel to melt the upper surface, or provide power, or both.
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The biggest problem with it all was as in all things Portuguese was the volumes of paperwork, it feels like it's the equivalent of war and peace three times over!

Its not for everyone but it works for us.

That's interesting; I'd like to hear how it's working out economically, especially if you're able to work out if the battery is paying for itself.

Also, who did your installation, if you can recommend them to others in the area.

Is the battery paying for itself is a difficult question to answer.

You have to look at when you would use the battery, the obvious answer is at night when the sun has gone down but if most of your use is during the day then is the investment worth it for a small reduction in mains cost for night consumption. On the other hand, if you use a lot of consumption on a night, air conditioning for instance then yes, a battery may be worth it.

You’re then faced with the question as to how much capacity you need. Typically, with expandable modules the first battery is the most expensive because it includes the base for the first battery unit and the top which houses the controller. Each subsequent battery costs far less because you’re only buying the basic battery pack and just sitting it in the tower. You then have to decide what size modules you want to build it from, for example 3kw or 5kw or as in my case 7kw. You can’t mix and match. Until you work out your anticipated and projected consumption you can’t work out how much capacity you need.

Equally, if you buy a pack with more than one battery (from a reputable manufacturer) the packs should be matched perfectly and will give a better output than buying one battery now and additional one/s at a later date.

You then have to look at how you’re going to measure the return, what happens during the day if you’re using the maximum from the PV panels, say several appliances and a three-phase welder and a cloud crosses the sun, if it seamlessly draws from battery pack rather than from the mains to make up the shortfall how do you measure this against the outlay.

If it’s a cloudy day and you still have spare capacity in the batteries and this makes up the shortfall from reduced output of the panels you need to consider this as well.

Another point to consider is, do you change your lifestyle to suit the power you have available, i.e you’ve had the benefit of charging the batteries all day so, do you start to consume power on a night (i.e. air conditioning) because there’s no add on cost but you wouldn’t if it wasn’t available from the batteries?

On top of all this you also have to factor in how many panels you need coupled with their output and orientation. If you can fit them all in given elevations with no possibility of shadow coverage you shouldn’t need individual optimisers and if you can do this for say two elevations, you’ll need an inverter with only two stings.

As you can see not an easy question to answer.

I ask because I hear that batteries are cheaper, but I need a lot of convincing.
Especially after a "reputable" firm in my area told me a pack of lies about the economics of them (immediately going back on those claims after I asked for hard numbers).

So, 14kwh battery; if I buy a kwh from EDP, it costs 20 cents. So the entire capacity of your battery is worth 2.80. Lets say you manage to charge in daytime and then use at night 80% of that, 200 times per year, we get value of 560 euros per year; which is really pretty good.
If the battery lasts 20 years, which would be 2,000 80% cycles, that would amount to 11,200 euros. That does not include interest on the initial outlay, but actually we're leaving out all sorts of things. The charge controller and associated parts, the capital gains or losses on the equipment, future prices of electricity.

I don't know if those batteries do 2,000 cycles either; but you get where I'm going. This is the calculation that needs doing.
So, how many cycles does the battery maker claim, and what did the battery cost?

Another way would be to check your nighttime power use, assume a percentage that the battery would supply, and figure out if it costs less than the power bill.

Of course these numbers can also change in future; the price of electricity might go up, or could even go down (I doubt it though). The price of batteries could go either way.
There is also risk and reward in owning your own equipment, longevity of the panels, inverter, controler, and batteries is not sure, past the short warranty period.

I feel as though I’m having to defend my decision to use batteries. As I said in my very first post it’s not for everyone. I have no vested interest in convincing people to use solar with or without batteries.

If you want me to comment, the warranty typically is 15 to 20 years on a battery pack. Your assumption is based purely on night-time usage. As I tried to explain, if its controlled correctly there can be an advantage to daytime usage when the PV panels are not producing at maximum, Also as I tried to allude to its not just using the batteries, its also making use of strategically positioning the PV panels to make use of the sunshine from sunrise to sunset not just at the peak times hence more strings and use of optimisers. This enables the panels to take every opportunity to charge the batteries even without full sun as well as providing power to the household. It needs to be a complete solution planned very carefully. By doing this I know you can achieve more than the 200 days you assume.

Just searching the internet there is currently a 15kw Huawei full battery pack (3 x 5KW batteries) available in Germany for 5,484 Euro’s.

I’ve no idea what your “reputable” firm told you about them, I was referring to using a reputable component manufacturer to provide a matched battery set, that’s nothing to do with the economics of usage.

I feel I’ve said all I want to say on this matter.

I'm building a new villa in central portugal... There's an unobstructed flat roof 6 x 8.5 m - solar is the obvious solution, but also does anyone know if there are grants from https://www.fundoambiental.pt/ or others to assist with installing a reversible heating\cooling heat pump?
Given I'm not resident (yet) and its a new build it could be a stretch.
Haven't decided on batteries yet. Heart says go large on the new stuff, head says may not get my money back.

Grants ended last November unfortunately - discontinued for 2025

Thanks everyone for the input , I think I will pass in the meantime. Perhaps the available deals may improve in future.