Are North Facing Solar Panels Worth Installing?

Should I invest in north-facing solar panels on my home? That's the question I'm going to answer in this video using data collected from my existing south-facing solar panels and a simulated solar forecast for some 'fake' north-facing panels. Full article here: www.speaktothe...
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[@Plan3tBob]

As a slight spin on this for others who are considering north facing panels where it makes a LOT more sense: If you are considering North facing panels being fitted at the same time as south facing panels then the payback can be a lot less. I say this because a huge amount of the cost is 'everything else'. For example I'm getting 13 s facing panels with the inverter, battery, Eddi, Zappi and the added cost of putting another 13 panels on the north side only increases the project cost by about 20% (it adds around £4k on a £20k project) and in that case, adding another 56% of generation for an increase in cost of 20% can indeed make sense. FYI, my figures almost perfectly match yours at 56-57%

[@SpeakToTheGeekTech]

Yeah if I'd had the budget to do it with the initial installation then I would have, but I had to cap the cost somewhere

[@waqasahmed939]

This is a fair shout. I think for my parent's house, they've got an attic on their south facing side. Realistically, I'd want to get that planning permission, get that attic reinforced and then put solar panels on the entire roof

[@VillageVidiot100]

I applaud the lengths you've gone to to model this! Consider using a tool like open solar to do it - it will be much quicker. I have put North and South panels on my shed. 4 X 400w identical panels on both elevations at 22.5 degrees pitch. The Southerly elevation is at about 215 degrees the North at about 35 degrees. On a full sun day the North generates about 70% of what the South does which is exactly what the modelling from open solar said it would. The interesting thing though is that on a a flat light day i.e. the days you are struggling for power, they generate almost exactly the same amount. With my system I have lots of excess on a full sun day but I do struggle to keep the car charged if it's grey so the North panels are 100% worth it. North roof on the main house needs repair at some point in the next few years so they will be going on there too when it happens.

[@SpeakToTheGeekTech]

I've bookmarked Open Solar to have a play with, thanks.

[@bobgriffin316]

It is interesting that north and south are almost exactly the same on a cloudy day. That means that north facing panels will make a big difference during the winter and when the electricity produced is low.

[@sparks1372]

Another good video. It is worth noting that during the winter the best days for those panels will be the overcast days when there is more light bouncing off the clouds. These are usually the low yield days so the north facing panels outperform essentially when you need them more. Also the pitch of the roof is important; the lower the pitch the better and as they will catch more direct sunlight earlier/later in the year.

[@SpeakToTheGeekTech]

Good points, I did actually notice that the difference between forecast north and south generation was closest on overcast days so that might explain why.

[@TheRonskiman]

Exactly what I was thinking. Also you could use a tool like Easy PV to give a yearly estimate of production.

[@MrKlawUK]

I have my north panels installed now. Only had them for a week but on a couple of sunny days this week I’m getting 3kw (inverter limit) from my 4kwp panels. thats in early/mid may so bodes well for the rest of the sunnier months. Hoping indirect sun means they’ll be useful in later months too.

[@SpeakToTheGeekTech]

Fingers crossed :)

[@osholio]

I was told by my solar installer during the survey that north-facing panels are approx. 30% less efficient in the UK, so may be worthwhile if the panels are cheap or it's all part of the initial installation.

[@SpeakToTheGeekTech]

I think there are many factors affecting their efficiency by comparison, but my calculations seem to suggest they are 43% less efficient if installed on my home. I guess the only way to now for sure would be to install them and look at the real data, but that's a costly experiment :)

[@waqasahmed939]

@@SpeakToTheGeekTech See I've wanted to get north facing panels for my parent's house, but only because they may well be eligible for certain bits of funding. I'm not eligible for any eco4 funding

[@shaneturner4630]

@@SpeakToTheGeekTech if all the hard work is done with the installation of the original panels and hybrid inverter & wiring etc.,, shouldn't it not be that much to install more panels on the opposite roof as everything else is in place just the fitting kit labor and panels cost.

[@SpeakToTheGeekTech]

@@shaneturner4630 Unlikely - the majority of the cost would be in terms of scaffolding and labour, that's the most expensive part of the installation usually.

[@BoyvanHeugten]

I would buy used panels that are like 5-8yrs old to get a hefty discount on the purchase price. Depends on if you can get your hands on such panels however. Their production will be lower but the point is that you have space on the roof you can put to work generating electricity, no matter how much that would be

[@SpeakToTheGeekTech]

That might save you a few hundred pounds, but the issue really is that the majority of the cost incurred is from labour and scaffolding for the installation. Certainly that's the case in the UK. If you are able to self-install then the maths suddenly changes considerably for the better!

[@NacNacMOTT]

Thanks for this video. I am glad I only found it after I made my decision as this may have it. I was also doubtful at first with NW panels but while I used the same approach of simulation mine took min. I went on the UE website for radiation statistic. Put my Existing SE ARRAY 4kWp from 2016 (efficiency 15%) and got a kWh/year about 13% than my yearly average over 7 years. Then I changed the orientation of the roof to get the kWh for the NW and got about 25% less (you find 50% less, interesting this makes the calculation more conservative). Then taking into account that the new panels are now 21 to 22% efficient, better with the 200W/m² (low light) curve, and that I can get an array about 50% more powerful. I concluded that they will generate at least if not more than my SE panels. I also know from my auntie who get her panels last year with an array split between W and E facing that with her 3.6kWp she produces more than mine. I am therefore confident that my NW panels will double my overall (SE + NW) generation. It took less than 6 year to get my return on my SE panels (cost 6k) Consequently, I convinced myself that having NW panels was a no brainer and it took me about 5 minutes. Time will tell if I was wrong or not....

[@SpeakToTheGeekTech]

I do hope that works out for you. The worst case is that it just takes longer to pay you back than you planned I guess

[@MrKlawUK]

going north because (1) I want a battery so the 0% along with solar is some saving; (2) I only have a 2.6kw south array as they’re old low power panels from 2012 but they’re FIT so don’t want to disturb yet. Eventually when FIT runs out I’ll swap the south with 4kw hopefully

[@SpeakToTheGeekTech]

That’s a very good scenario for them being worthwhile then!

[@waqasahmed939]

I did consider it still being useful with Octopus Flux. This is especial true if you can get some free funding out there. Right now, my bank balance feels very... light lol

[@hicksonb]

So I got a quote to do this and it was €4,000 for 10 panels, roughly £3,500. And I know this was a ‘don’t want to do its price’ from my installers. Having watched 2 recent videos 1 by the EV Man on Bifacial panels and another by upsidedown fork on North facing I’m now even more set on doing this. And I know I will get a roofer myself to install the rails and panels and the cable up myself with a spark to do the last mile. Not for everyone I know but if you can you should!

[@SpeakToTheGeekTech]

Yup, the more you do yourself the more worthwhile it is! Those bifacial panels would make a huge difference too.

[@mondy-chan]

nice idea, will integrate this into my HA! also, 6k for 4kWp is extortion pricing

[@SpeakToTheGeekTech]

Seemed quite reasonable to me compared to the other quotes I had and from what other people have said they'd paid. That included an Eddi and optimisers. That was a couple of years ago, not sure what the going rate would be now.

[@derekgoffin5807]

I would assume a smaller extra inverter. Surely 1 the North Wcfacing have less output per panel and 2nd your 2 arrays will have very different peak outputs?

[@SpeakToTheGeekTech]

Tricky... likely less peak per panel, but potentially more panels meaning the peak could be about the same. Probably a 3.68kW inverter is still sensible as there are plenty of those around to choose from so very cost effective. It's all just a thought experiment really anyway as I won't be doing it! :)

[@christophmartin5381]

We have a south and north face P system. The south system was build 16years ago and cost nearly 80.000€ at that time. It has roughly 15.000KWp. The north facing system is 2 years old has 18.000KWp, well this system produces indeed less energy , roughly a ratio 3-2 but here comes the Kicker, the new system just costs 25.000€ inclusive a 10Kw/h battery.

[@SpeakToTheGeekTech]

Very nice, I guess you've found the optimum cost model for it!

[@christophmartin5381]

@@SpeakToTheGeekTech Yes, the time difference / cost difference makes it interesting. If we had no PV system at all and we had to make a decision now, I would not use the north side. Additionally there is one mechanism that makes it interesting. Subsidies, the financial benefit combined with a battery is highly intersting and the system amortizes after 7-10years , depends on the KW price from your energy supplier.

[@drbyte2009]

Interesting video, i'am also going to install the forecast integration, and see what the difference is between forecast and reality. Thnx !!

[@SpeakToTheGeekTech]

The forecast integration is great for this particular scenario, however if you'd like slightly more accurate and longer range forecasting then have a look at the Solcast integration. You need to install it via HACS though (check out my other video on installing HACS if you're not sure about how to do that: kzbin.info/www/bejne/oKvTnmtvbppphtk)

[@drbyte2009]

​@@SpeakToTheGeekTech Thanks a lot, I'll look into it and try it out on my test environment🙂

[@drbyte2009]

@@SpeakToTheGeekTech What is the easiest way to determine the position of your solar panels?

[@SpeakToTheGeekTech]

Position as in latitude and longitude? Google Maps is the best, just stick a pin in the location and it displays the co-ordinates. For the direction it's facing, a compass is best (even one on your phone).

[@drbyte2009]

@@SpeakToTheGeekTech I ment the facing direction of the solar panels. I wil check with my phone !

[@PetrusB83]

I think it makes more sense to consume more of your existing power. Batteries are an option, but a cheaper option would by something like and Eddi from myenergi. The payback would be much faster. I am also considering North facing panels (that's how I got to this video), but I first want to ensure I capture all the power generated by my South facing panels. Getting closer and I think once I have an EV I should be able to consume most of it as I work from home so the car is charging during the day.

[@SpeakToTheGeekTech]

Export tariffs (in the UK) are generally so good now that it’s rarely making sense to use your generation over exporting. If you had Intelligent Octopus Go for example you could export at 15p whereas import off peak is 8p. Charge batteries and heat water off peak, export as much as you can at peak.

[@PetrusB83]

⁠damn, that’s good. We don’t have time of use easily accessible in Germany yet. So I pay 24€cents per kWh for import and only get 8€cents per kWh for export. Will probably have to start looking at getting time of use as well.

[@MrKlawUK]

is there a reason to use solar forecast rather than solcast? I’m using solcast for my south array which gives a nice prediction curve look ahead which is useful. I don’t know if you can add a second one though..

[@SpeakToTheGeekTech]

You can add two sites in Solcast under their free account. Solcast seem to be dissuading free users from their service now and the current trajectory suggests that they may kick us off altogether in the future. As it stands I find it the most accurate and useful forecast, but forecast.solar is a close second. I used forecast.Solar for these fake array tests because I only need day-ahead data and didn’t want to use up my Solcast sites for it

[@RichardABW]

Might not apply to you but would be interesting to compare a system with a north/south split on a single inverter and battery. You don’t need another inverter for the north array, just a bigger one, and they don’t cost much more.

[@SpeakToTheGeekTech]

Yeah I’d love to try that out but I have to live with my investment for as long as possible now

[@RichardABW]

@@SpeakToTheGeekTech I think you have a SolarEdge inverter. If you ever wanted to swap to the new Home Hub inverter (SolarEdge are doing an offer where you get a free backup interface if you're upgrading from their HD Wave inverter) then there's your opportunity to switch to an SE5000H, SE6000H or whatever.

[@thomasjacques5286]

Highly informative and presented video. In a way I guess I'm lucky that my home faces due EAST/WEST here in southern Illinois (20 miles from St Louis) and with that orientation 31 405-watt Q Cell panels along with Enphase IQ8A Inverters are predicted to generate almost 13 kWh or about 14K kWh a year when my annual average consumption is 11,600 kWh. I oversized my system to support future batteries and any system degradation as may occur. I do have room to add about 10 more panels should the need arise in the out years. By then I hope panels are processing far more power than the 405 I'm getting today.

[@SpeakToTheGeekTech]

Thank you. I wish I had that much space for panels but that’s quite unusual in the UK

[@waqasahmed939]

Another thing to consider with that price is Insulation, windows, doors, MVHR etc... Those will give a better return than north facing panels in the northern hemisphere.

[@SpeakToTheGeekTech]

Not sure there is much in the way of grants for solar at the moment :(

[@jmpcrx]

Gotta go diy for all this stuff to make it worth it. I did 😁 and its awsome. 2.5 years pay back.

[@SpeakToTheGeekTech]

I wish I could. I know my DIY limits though!

[@piotrr597]

Idk how You calc this cost, only panel, or panel + inventer, but ... If We have a instalation from S and add N, all to one inverter 2/4 MPPT. Or microinverter then this excel should by looks different.

[@dedskin1]

it should not be hard to calculate this but can you use small panels , like real small say 10x10 inches , and place them , and do calculation for them , im wondering is it worth it .

[@SpeakToTheGeekTech]

I don't think the physical size of the panels makes much of a difference - maybe a bit more installation effort and cost. In terms of my calculation, you put whatever your installation costs are into the spreadsheet. Doesn't really matter to the spreadsheet whether you have 300x10w panels or 10x300w panels.

[@dedskin1]

@@SpeakToTheGeekTech These are spread sheets computer simulations , its not what happens in real world . That is why i asked for a practical experiment , as you say doesn't matter how big the panel is its scalable , but the output of it over say 1 year , real data , real time tracking . Now that would be a guide . I cant of course ask of you to do something for me , im just saying its a good test . I will probably do it on a small scale then see how it performs .

[@Bushtuckerman71]

At the end of the day when everyone is making dinner the kwh market price is higher than the average day price and the electric self consuming high.

[@SpeakToTheGeekTech]

Yup, and that's what my batteries are for

[@charliebadcock9142]

Great video, in a few years time get new panels onto the south facing and move the old to the North facing. Now how to model that in a spreadsheet?

[@SpeakToTheGeekTech]

That would be tricky! I like the idea of re-using what I have, but given the cost of putting scaffolding up and paying someone to move them over, the actual cost of newer more efficient higher wattage panels in a few years would add only a few hundred pounds to the bill of a few thousand. Not sure how to model the benefits of doing that though, there are so many variables and unknowns!

[@Est-lj4tq]

Best to get a used set and install em yourself. Otherwise Roi will be long

[@SpeakToTheGeekTech]

If you have the skills and ability then go for it. It's beyond me personally though, working on the roof, I wouldn't survive to see them powered on!

[@drbyte2009]

Do you know a way to calculate the power consumption between sunset and sunrise?

[@SpeakToTheGeekTech]

Yes, check out my offpeak tariff automation in this video (Off-Peak Tariffs In Home Assistant's Energy Dashboard kzbin.info/www/bejne/mJOYkneqo5eqi6M). Instead of the trigger being a time helper it can be set to sunset and sunrise, and the tariffs can be named day and night. You’d end up with two entities from the utility meter, one tracking day energy, the other night energy

[@drbyte2009]

@@SpeakToTheGeekTech Thnx a lot, I will take a look👍

[@drbyte2009]

​@@SpeakToTheGeekTechSo if I understand you correctly I don't need the two timer helpers, instead I can set the triggers to sunset and sunrise in the automation.

[@SpeakToTheGeekTech]

Correct

[@drbyte2009]

@@SpeakToTheGeekTech Thnx 👍

[@ManChickin]

to be honest... the only real way to get a good return on North face panels is to fit them yourself

[@SpeakToTheGeekTech]

Yup I think I probably agree with you on that!

[@adblocker276]

Why not just use data from PVGIS your simulations could’ve been done in a few minutes at most instead of wasting numerous months.

[@SpeakToTheGeekTech]

Well that would have made a boring video though wouldn’t it? And PVGIS doesn’t know everything…

[@adblocker276]

@@SpeakToTheGeekTech fair enough but I hadn’t watched the video - it may be helpful for others if the alternative (easier may be less accurate version) was also mentioned. I did the maths for my own north facing installation.