Looking for Recommendation for PV Advice

I have in mind quite a large installation of Photo Voltaique solar panels on our larger barn. I would like to both store and to feed back to the grid.
We are embarking on a project that will have very high electricity demands. I am hoping that I can reduce the energy costs with a PV installation but have no idea where to turn. I can find many companies that want to call me for a hard sales call. I really want to sit down in front of someone to discuss this. It may even be a non-starter in terms of costs or viability.
Does anyone have any recommendations for companies in the Aveyron/Tarn region that can supply a consultation?
Whilst my French is getting better, someone with a level of English communication would very useful; I suspect some technical terms may be beyond my ken.

Hi Martin…

Why not look at the EDF/Enedis sites and see what they talk about…with regard to photovoltaique …

there is usually lots of information if you dig a bit…

(you will need permission from the Mairie…

and it might be worth letting them check any paperwork “before” you sign anything that is written in French. Our commune has been badly hit by “naughty-folk” who have taken advantage of our non-french speakers.)

It is those pesky sales people I wish to avoid …

I am thinking that thsi oud be classified as a small commercial energy project. I want to generate and store enough to be able to supply ~36kVA on a 3 phase circuit, and to do so for a 3-4 hour burst, once a week. This is likely to cost quite a bit and will be a considerable investment. I don’t mind paying for someones time to provide expert advice and consult on this. Even if it proves that this is not a viable project.

The majority of online sellers want clients to sign up to long-term tax-credit contracts. You can have a small PV installation for just one euro, after 10 years your tax wil have been reduced by the amount that you have to pay out. If I read their small print cynically enough :slight_smile:

Our beermaking has just started to get serious!

We had some terrible situations and some folk will be paying-off the “loan” for the rest of their lives…:zipper_mouth_face:

Indeed, what we have in mind would take a lot longer than that, certainly far more than I have left.

Yes, but you will, presumably, be enjoying some benefit from it all… during your lifetime :thinking:

That is the plan, Stella :wink: Especially beer made with the power of the sun…

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Have you got this 36kva available to you now?

We currently have a 20kVA 3 phase supply. I know that needs upgrading, we have until December 2019 at the earliest to get the electricity sorted. Does what we have today restrict what we can do in the future?

Very much so if you are thinking of generating a higher voltage than the amount coming in you will have all sorts of problems only an expert can really give you the reasons but we have been there with equipment that required a large 42KVA 3 phase supply, we used to trip all the boxes when we started up our Electric irrigation pump to pump water out of the river to irrigate our fields of maize till we had all the necessary safety equipment installed.
Also, bear in mind the standing charge for a business tariff requiring 36KVA which will be around €120 per month plus taxes before you even use any electricity.

Sounds like there are two basic options

  • Install enough panels/large enough inverter to supply 36kVA (I assume you mean 36kVA total, not per phase) in which case the 3-4 hour burst will be supplied from the system and the rest of the time you should have plenty to sell back to the grid.
  • or, look at an off-grid system allowing you to charge batteries from a smaller panel, then supply the 36kVA burst from the batteries. 36kVA for 4 hours is (depending on power factor) 144kWH; as a 100AH 12V battery is 1.2kWH you are going to need quite a few batteries.

There might be hybrid systems wich allow an off grid system to actually be on-grid for feed in but my (completely theoretical) knowledge of PV systems does not stretch that far.

As Mick says you need to talk it through with an expert.

Michael, that sounds as if your situation was different unless I misunderstood. You were drawing a large amount from the grid? Whereas this is generating from solar.

Sounds like a job for a Tesla powerwall installation or super capacitor.

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Yes, you are correct John with my situation, great that SF as the experts freely available with their sound advice.

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Thanks guys.
I am thinking along the lines of a Tesla powerwall, they are not the only suppliers the market is catching them up I believe.

We will have 3 12KW 3-phase heating elements, one to heat 1,000 litres to 84degC, the other 2 to heat a similar quantity to boiling and hold it there for an hour. As such I do not anticipate any large surges on start up.

I do realise that I need to speak to an expert, I am trying to ask if anyone can recommend such an expert?

The data I’m looking at for the Powerwall 2 says 13.5kWH and max 5kW output which sounds undersized for your needs by a factor of around 6!

When I get home I’ll work out how much energy you will need, that might shed some light on the project.

Can’t help point you in the direction of an expert I’m afraid :frowning:

Indeed, but Tesla do say that up to 10 units can be stacked together. At a max continuous drain of 3.68kWh/unit that should give me 36.8 :slight_smile:

Have you experience of heating 1000l (one metric ton) of water with your heaters.

A bit of back of the envelope calculation suggests that you are out a little in your energy calculations.

it takes 4.2kJ to raise the temperature of 1l of water by 1°C.

Assuming the water starts at 12° you need a 72 degree rise for the 1000l that you want to get to 84°

72 x 1000 x 4200 is 302.4MJ

1kWH is 1000 x 60 x 60 = 3.6MJ

So to heat 1000l of water to 84 degrees would need 84kWH

With a 12kW heater it will take 7 hours.

All of this assumes no losses.

To get to 100° - I assume that you don’t actually want to boil the water if possible as this takes way more energy than just heating it needs 102.7kWH and will take 8½ hours - again, no losses included.

So for your total of 3000l of water you need 289.3kWH or 22 Powerwall 2’s

And that’s before we consider holding it at temperature for an hour or so

That’s a lot of 'leccy :slight_smile:

Whwn heating to 100degC, the starting temperature will be around 74degC. After that we cool the liquid by passing it through a heat exchanger, the water that is heated in the heat exchnager is stored as the next batch to be heated to 84. So, the next 1,000l start at about 50, not 20degC. Once the system is initialised, we try to recature as much energy as possible. Initialisation, and heating for the subsquent cycles, shall be done during Heures Creuses.

OK, that makes it sound rather more plausible :slight_smile:

50->100° will still be 58kWH, around 5 hours with a 12kW heater.

I started out with the gut feeling that meeting your requirements would be best met just with raw panel area (assuming you have enough space). I’m feeling that even more strongly even with the aboev info given that you are looking at north of £40k for the Powerwalls that you would need.

That bit has the 2x12kW heating elements :slight_smile: