Using solar power in regions (like Alaska) with little sunlight in winter?

[math55]

In my region (in Sweden) the winter months are quite dark, there is some sunlight, sun goes up at around 9am and goes down at around 3pm. I used a calculator which said I can produce 3600kWh a year in my region using solar panels. Just for my understanding, can I not "get" more solar power from the sun that is shining the more panels I install? There is a difference between having 2 panels or 20 when the sun is out, isnt it? So cant I not for example produce 7200kWh a year by just having more panels and of course the matching equipment like the MPPT and batteries?

I'm not sure if I'm going to invest in solar, or have power put in. Is it even possible to run soley on solar power in regions like mine? Would you recommend having a generator as backup?

Thanks

 

[Rednecktek]

Pinging @upnorthandpersonal ! This is all on you buddy.

 

[SamDeleted]

can I not "get" more solar power from the sun that is shining the more panels I install?

Yes correct, the more panels you have, the more power you will make



In the UK we suffer similar issues with lack of sunlight in winter, the rule of thumb for us is , 5x rated capacity in summer , 1x in winter


So a 1kw solar array will produce on average:

5kwh a day in summer
1kwh a day in winter

(And roughly 3kwh per day spring/autumn)

 

[SamDeleted]

I'm not sure if I'm going to invest in solar, or have power put in. Is it even possible to run soley on solar power in regions like mine? Would you recommend having a generator as backup?

Here take a look at this man in Finland....

My 44kW vertical and bifacial set in Finland.

New to the forum, new to the solar energy. Have 63 Bluesun bifacial 700W N-type shingled panels, 22 old electric poles, shit load of underground cable, 51 x 6m 40x40x3mm marine grade aluminium, 2 Bluesun 15kW on-grid inverters, 2 Deye 15/12kW hybrid inverters, 30kW lead acid battery and 4 x 5kW...

diysolarforum.com

It is totally possible to go off grid , even in the artic circle. Just takes more careful thought and financial investment. A back up generator is ALWAYS a good idea , consider desiel or more likely LPG(propane)

 

[math55]

Alright, so those 3600kWh depend on the amount of panels so to say ... got it, just the number without knowing the amount of panels is useless.

Thanks!

 

[upnorthandpersonal]

So, yeah, as others already mentioned: the more north you are, the harder it is to do winter with solar. I'm at 63 degrees north in Finland: no matter how many panels I would put, I wouldn't make enough during the winter months since we barely have any daylight (November, December and January).

In my opinion, you should leave these months out of you calculation of array size. Aim to make it from February through to the end of October. If you're off-grid, have alternatives (for example I cook on induction in summer, but propane in winter. Heating/hot water in winter with wood). I also use a generator in winter, which I power using bio-diesel I make myself. If you can lower the amount of power needed in winter, you don't even need to run it all that often to charge the batteries.

 

[DIYrich]

In the UK we suffer similar issues with lack of sunlight in winter, the rule of thumb for us is , 5x rated capacity in summer , 1x in winter

Enough excess power in summer to run AC to make it feel like winter!

 

[math55]

Thanks for all your ideas guys! Little example to see if I got the math correct:

Lets say I need 5kWh a day in winter. Would I need panels that sum up to ~25kW so I get enough in winter? If so, which equipment would I need? Is a battery with a capacity of 5kWh (like the Growatt APX 5.0P for example) enough or would I need more because there are 25kW coming from the panels (in summer)? Same question for the inverter, would a Growatt MOD 6000TL3-XH suffice or would I need more because of the many panels? Would it be too much energy in summer for the inverter and the battery?

Thanks again!

 

[SamDeleted]

Thanks for all your ideas guys! Little example to see if I got the math correct:

Lets say I need 5kWh a day in winter. Would I need panels that sum up to ~25kW so I get enough in winter? If so, which equipment would I need? Is a battery with a capacity of 5kWh (like the Growatt APX 5.0P for example) be enough or would I need more because there are 25kW coming from the panels? Same question for the inverter, would a Growatt MOD 6000TL3-XH suffice or would I need more because of the many panels? Would it be too much energy in summer for the inverter and the battery?

Thanks again!

Hi Matt

No that's not correct sorry , I'm not sure on the exact figures for your country

I would imagine 25kw of solar panels would make at least 15kwh a day average.

BUT BE AWARE , that is average , some days that will make 40kwh , some days it will make only 5kwh , that is why we have battery back ups and generators


Generally you should have 3 days worth of battery , if you need 5kwh a day, you want ideally 15kwh of batteries

 

[math55]

Thats what I meant, some days it will only make 5kWh, thats what I would need in winter. Of course, in summer it would be much more ... thats what I am trying to figure out, what happens in summer when it makes a lot more ... will the energy just be lost if I only had a 5kW battery or will something blow up :-D?

 

[upnorthandpersonal]

what happens in summer when it makes a lot more ... will the energy just be lost if I only had a 5kW battery or will something blow up

You'll just lose the energy. If you don't take it from the panels, it will just be turned into heat - just as if you would have a black painted piece of wood standing there. Note that this forms no issue with overheating.

 

[DIYrich]

Thanks for all your ideas guys! Little example to see if I got the math correct:

Lets say I need 5kWh a day in winter. Would I need panels that sum up to ~25kW so I get enough in winter? If so, which equipment would I need? Is a battery with a capacity of 5kWh (like the Growatt APX 5.0P for example) enough or would I need more because there are 25kW coming from the panels (in summer)? Same question for the inverter, would a Growatt MOD 6000TL3-XH suffice or would I need more because of the many panels? Would it be too much energy in summer for the inverter and the battery?

Thanks again!

You need an inverter that can handle the max pv being produced in the 1 hour of winter sunshine a day. You also need a battery that can absorbe that much power that quickly. It may cycle daily between 40-60%.

The 25kw of panels may only produce a fraction of the rated max in winter.

If you only need 5kWh per day, I'm guessing 10kW of panels would produce 5kWh in one or two hours on a good day in the winter.

5kWh of charge speed implies 25kWh of batteries to be at the .2c charge rate. 15kWh would probably be ok at .33c. But with 25kWh you have 5 days of power for gloomy days.

 

[RV10flyer]

To give you a comparison….in Ky with 32kWpv my max production is 185kWh/day, my lowest on a very dark cloudy winter day with no snow on panels is 8kWh. If I need to run my 10 kW LP generator, then I’m adding more PV. So winter minimum can be 4% of summer max. Have fun harvesting up there.

158kWh of diy LFP for my home system.

 

[kommando]

Go to this website and enter all the details of your location, direction and angle of the panels etc and set the panel array size to 1000W.

This allows you to then multiply any month by the actual planned array size eg by 5 if you decide on a 5Kw array

JRC Photovoltaic Geographical Information System (PVGIS) - European Commission

Photovoltaic Geographical Information System (PVGIS)

re.jrc.ec.europa.eu

Download the data including the monthly forecast to get an idea of how Dec compares to Jun, you will end up writing off Nov to Feb for providing any meaningful production.

I am on grid using oil for space heating and hot water, I have an automatic diverter that diverts any excess solar production into an immersion heater. From May to Sept the heating is never on and all the hot water we need comes from the diverter. Oct to April the oil heating does the space and hot water. So the solar being low in winter is not an issue, no excess is made but its not needed. I do not send any excess to the grid as its a DIY install and does not have the right certs for selling into the grid but I save a lot of oil in the summer which more than makes up for it.

I am at the same latitude as Southern Sweden eg Halmstad.

 

[MattiFin]

Go to this website and enter all the details of your location, direction and angle of the panels etc and set the panel array size to 1000W.

This allows you to then multiply any month by the actual planned array size eg by 5 if you decide on a 5Kw array

JRC Photovoltaic Geographical Information System (PVGIS) - European Commission

Photovoltaic Geographical Information System (PVGIS)

re.jrc.ec.europa.eu

Big recommendation on this tool. (altough I get really funny results at the moment if going above artic circle)

Alternatively give us better specs where you are located, what sort of consumption you are envisioning and so on.

5kWh per day might be feasible in most southern part of Sweden, ie good location in Skåne with 15kW of panels and 50kWh of battery capacity.
(This is easily 25000 EUR setup)