Solar panel output high latitudes?

[sailingrock]

Above 50 degrees latitude, what kind of output will solar panels produce in the real world. "Real world" as in typical weather conditions?

Say for rigid or flexible.
As compared to nominal wattage.

Say 10 watts/ft^2???
Say 5 watts/ft^2???
Say idk cuz sci ain't my thing.




Do zombies need solar, really?

[El Pinguino]

Solar panels prefer cold weather to hot weather, they are more efficient in the cold.
You want panels that can be 'trimmed to the sun' rather than just laid flat on some metalwork monstrosity down the back of your boat... ideally this means mounting on either your cabin top or on the lifelines port and starboard with an adjustable mounting system.

[StuM]

Horizontal or tilted panels?



Watt/m² varies throughout the day so you are better off talking about Watt hours /m² per day or month.


(To answer you question directly, it varies constantly between about 0 and 200 W/m²)



The further from the equator you go, the larger the monthly difference in total insolation. Even with clear skies, above 50°, there's a huge difference in the amount of sunlight falling on a panel over a day between December and June.


Then there's climatology to consider. How often is it overcast/raining v clear sky in the location.
There are websites out there which will give estimates for various locations.


As an example https://www.researchgate.net/figure/...fig2_274947386


Norway in Summer gets 10 times as many Wh/m² in July as it does in January.

[john61ct]

In sunny weather when days are long - typical is a fantasy - rough ballpark use 1/3rd ballpark guesstimate.

300W averages 100AH per day into a 12V bank.

But so many variables. . .

And you need to size for worst case, so with high variability maybe triple what's needed on average. Ability to conserve usage is key when mounting space is limited.

Best as a supplement, not the only source.

[yachtgemini]

a data point for you..

we live and keep our boat at N50 in the UK and have 400 watts of Kyocera hard panels flat on an arch at the back. For most of the summer, we easily exceed 100ah per day and peak about 130ah. But grey winter days (like today) will get as low as 25ah. We have always augmented our system with a wind turbine and find that usually, you have either wind or sun but rarely both.

Ross

[Paul Howard]

We had 360watts of solar panels mounted flat on the arch of our catamaran when going into high latitudes. At the Arctic Circle (66degrees30'North), while at the north of Iceland, it never got really dark, though we did get a sort of short twilight as it got towards the end of July. I did not measure the amount of power from them, though the increased hours of daylight seemed to make up for the higher declination of the sun but shorter hours of sunlight and long nights of dark of the tropics. We did not seem to run the engines more to charge batteries, and solar panels were still very much valued for their output.
Of course, during the winter there is no sunlight at the Arctic or Antarctic Circles, but even at 50degrees latitude north or south (We also spent a southern hemisphere winter on board on the Beagle Channel alternating between Puerto Williams, Chile, and Ushuaia, Argentina, about 55degrees latitude South, on the same catamaran with same solar panels) and only got about three to four hours of sunlight low in the sky at the height of winter, though long twilight and still got some output from the solar panels. So if the question is: Are solar panels worth having in high latitudes, the answer is yes.

[Jammer]

Originally Posted by sailingrock

Above 50 degrees latitude, what kind of output will solar panels produce in the real world. "Real world" as in typical weather conditions?

My house is at 44 degrees north.


Solar output in higher latitudes varies widely depending on time of year, and to a lesser extent the weather at the location in question. In general terms, if you tilt the panels, summer output will somewhat exceed the summer output near the equator, because the effects of the longer day exceed the losses due to the somewhat lower insolation angle.


If the panels are horizontal, then the summer output will be somewhat lower than what you would get near the equator.



Solar output in midwinter can be near zero, because of the short day (7 hours) and very low insolation angle. Many northern regions are prone to winter weather systems that produce continuous cloudy conditions for days at a time, further reducing winter output.


As noted upthread, cold weather improves panel performance, but these changes are slight.

[carlheintz]

We have solar powered floodlights throughout our commercial property in Holland, Michigan. The ones with near horizontal solar panels are often useless. Mount the panels at a 45 to 60 degree angle for much better performance most of the year. Hint: the snow will also fall off them at that mounting angle.

[bobgarrett]

As others have said, the angle of the panel is important. Horizontal panels will not be efficient.
Also remember that in higher latitudes in the summer the sun is up for long, and winter for shorter periods.
So in summer you get longer sun especially if the panel angle can be changed.

[desodave]

To add a question to the OP's, do the northern latitudes increase or decrease the advantages of a MPPT controller versus a PWM? Prime concern is about output during the longer daylight times between April and October.

[wrwakefield]

Originally Posted by sailingrock

Above 50 degrees latitude, what kind of output will solar panels produce in the real world. "Real world" as in typical weather conditions?

...

Following are two real world examples with data gathered a bit further N of 50°. [Data provided in watts so you can crunch the numbers to make your own conclusions and decisions based upon your own electrical system and needs...]

First example:

We are onboard our boat fulltime and traveled between 55° and 59° N in 2018.

The boat has 3 solar panels. [All rigid monocrystalline; each with their own Victron MPPT 75/15 controller. The 3 controllers share one battery voltage/temp sensor. These Victron controllers are the sources of the data below...]

For reference, our house bank is 900AH [nominal] @ 12V DC. Annual average daily energy consumption is ~2.2 kWh running 2 refrigerators and 1 freezer full time. Charging is also performed with a 10 kW generator driving 185A in battery chargers, and a 120A alternator on the engine.

The 3 solar panels on Denali Rose include:

1) One 130W [10 years old; slightly pivotable] on top of bimini. [More frequent shadowing in this location]

It produced 49 kWh in 2018


In the above photo, you can just see the corner of the solar panel on top of the bimini [and the horizontal tubing it pivots on...]— and one of our boat cats.

2) Two 165W [330W combined; 2 years old] mounted side-by-side as one assembly on top of davits. [Pivoting to optimize sun angle; Typically fewer shadows than bimini top location.]

These 2- 165W panels produced a combined 193 kWh in 2018.





Second example:

Family in interior Alaska [65°N] have 2 large grid-tie auto-tilt/tracking [max possible-output] solar arrays on a mountaintop [no shadows...] The 2 arrays have a combined capacity of 5.5 Kw.



Their data [kWh] follows: [Note the 2nd array went online in 2010...]



External factors influencing solar harvest: Aside from boat infrastructure shadows on the panels and weather, we are also subject to geographical factors that affect solar output on the boat; We often anchor in locations surrounded by tall mountains [e.g., 3-7k ft] and that frequently diminishes/eliminates direct solar exposure.

RE: Climate and Wx related factors: To get a feel for what to expect climate wise, I like to use Weatherspark.com and Climate.gov.

There are also many sites that focus more on solar aspect, but I prefer the big picture for climate data.

I hope this will help you determine whether solar power is worthwhile for you in the areas you are considering cruising.

Cheers! Bill

PS: We have a camper and 2 enclosed trailers stored at 56°N— each with their own 100W solar panel; rooftop mount; tilted 70°. These keep the respective battery banks topped up year around...

[thinwater]

Search a UK forum. London is at 51.5 and the rest of the UK is north. between latitude and clouds, they don't talk about solar as much up there.


I know that even in Maryland (39) it's a challenge in the winter.


Which leads to the question, summer vs. winter makes a big difference as you move north, because it is also about the length of the day; in the tropics there is little difference, but the actual useable part of the day may decrease from 14 hours in summer to 5 hours in winter.

[El Pinguino]

Near the winter solstice hours of daylight will be a major issue however I think another thing to consider is where you are.... f'rinstance you may be more likely to get clear days in Patagonia than on the west coast of the UK......

1/ Sun on the meridian ...ten days before the (austral) winter solstice in 55*S

2/ Late winter in Patagonia ... a not uncommon sort of a day.....

3 & 4/ the fancy mounts on the cabin top are - I think - of german manufacture...

[wrwakefield]

Originally Posted by sailingrock

Above 50 degrees latitude, what kind of output will solar panels produce in the real world. "Real world" as in typical weather conditions?
...

[Sorry for this repost, but the images disappeared from my first reply. Hopefully they will stick this time...]

_____

Following are two real world examples with data gathered a bit further N of 50°. [Data provided in watts so you can crunch the numbers to make your own conclusions and decisions based upon your own electrical system and needs...]

First example:

We are onboard our boat fulltime and traveled between 55° and 59° N in 2018.

The boat has 3 solar panels. [All rigid monocrystalline; each with their own Victron MPPT 75/15 controller. The 3 controllers share one battery voltage/temp sensor. These Victron controllers are the sources of the data below...]

For reference, our house bank is 900AH [nominal] @ 12V DC. Annual average daily energy consumption is ~2.2 kWh running 2 refrigerators and 1 freezer full time. Charging is also performed with a 10 kW generator driving 185A in battery chargers, and a 120A alternator on the engine.

The 3 solar panels on Denali Rose include:

1) One 130W [10 years old; slightly pivotable] on top of bimini. [More frequent shadowing in this location.]

It produced 49 kWh in 2018



In the above photo, you can just see the corner of the solar panel on top of the bimini [and the horizontal tubing it pivots on...]— and one of our boat cats.

2) Two 165W [330W combined; 2 years old] mounted side-by-side as one assembly on top of davits. [Pivoting to optimize sun angle; Typically fewer shadows than bimini top location.]

These 2- 165W panels produced a combined 193 kWh in 2018.





Second example:

Family in interior Alaska [65°N] have 2 large grid-tie auto-tilt/tracking [max possible-output] solar arrays on a mountaintop [no shadows...] The 2 arrays have a combined capacity of 5.5 Kw.



Their data [kWh] follows: [Note the 2nd array went online in 2010...]



External factors influencing solar harvest: Aside from boat infrastructure shadows on the panels and weather, we are also subject to geographical factors that affect solar output on the boat; We often anchor in locations surrounded by tall mountains [e.g., 3-7k ft] and that frequently diminishes/eliminates direct solar exposure.

RE: Climate and Wx related factors: To get a feel for what to expect climate wise, I like to use Weatherspark.com and Climate.gov.

There are also many sites that focus more on solar aspect, but I prefer the big picture for climate data.

I hope this will help you determine whether solar power is worthwhile for you in the areas you are considering cruising.

Cheers! Bill

PS: We also have a camper and 2 enclosed trailers stored at 56°N— each with their own 100W solar panel; rooftop mount; tilted 70°. These keep the respective battery banks topped up year around...