Going Solar

Our latest home improvement project has finally come to life and our new solar panels are online. This has mostly been Mr’s project. Not because I’m opposed to solar energy, but because I have zero time for researching, calculating and shopping for it. It took about a year from start to finish, and I won’t bore you with all the small and big  problems with banmks what waht have you not and present you our own small energy centre.

©Giliell, all rights reserved

Here you have a screenshot of that shows the energy use and production of our “power plant”. The image has 4 circles representing the different components, the middle circle represents the ac/dc converter. The top left corner shows you the current energy production. We have a maximum of 7.1 kwh, what you see here is 717 W, light clouds. The top right corner is the current energy use in the house. The bottom right corner is our battery. It has a maximum of 7 kwh, but it always tries to stay at 25% full in case of emergencies. Bottom left ist the interaction with the power grid. The dots going to the middle show you how much energy is going which way. All in all we’re currently very fascinated by the app. I guess this will wear off in a few weeks, but currently I keep checking it constantly.

One of the niftier components of the whole thing is a little (expensive) gadget that allows us to keep producing energy when the grid is down. With a normal solar plant, when the grid is down, your solar gets shut off. That’s sensible because you cannot safely repair a power line while thousands of roofs keep sending voltage. In our case, should the energy company send the signal tu turn off, our unit becomes its own closed circuit. Since experts have already predicted power outages to become more common, that seems like a sensible investment.

As you can see, our goal is to produce as much of our own energy as possible and I must say, for February it’s been good so far. One thing is that we do need to change our habits and try to use the electricity when it’s being produced, because I basically lose 8ct on every kwh I have to sell to the energy company. Years ago, before batteries were affordable, solar mostly went into the power grid and people got guaranteed high prices, making it a good investment. Friends of ours needed a new roof and didn’t know how to pay for it when the roofer told them that putting up solar would pay for itself and the roof. Those subsidies had their own problems, as they mostly benefited home owners and were paid by renters, but they led to a thriving solar industry. then those subsidies were cut, 100k jobs in solar were lost, and people stopped putting up new solar panels. Because if I calculate the cost of the whole thing and divide it through the expected kwh that it will produce, a kwh costs me 15ct while I get 7. But if I have to buy a kwh, I pay around 30ct, so I save 15 by using one that I produce myself.

Paradoxically, this has led to me occasionally using more energy on purpose, like today. It was a fairly sunny day and we produced 11 kwh, not bad for a day in February, which is about our daily use as well, but of course we don’t produce it evenly spread, so when I came home this afternoon, I put on the dishwasher on the high energy short cycle that only takes an hour. Because then the sun was shining, the battery was full, and I was selling my energy cheap. But if I  put it on the low energy long cycle, that would take 4 hours, meaning that I would have to rely on the battery for the later half of the cycle, draining it faster and making me buy energy tonight/tomorrow morning, which is a perfect example of something that is the perfectly logical and sensible decision for one person being a negative for society as a whole, but I’m not going to feel bad about it.


  1. says

    Fingers crossed, I do hope it will work as expected. I would love to go solar, but I am afraid that my old roof would not be able to bear the panels and I cannot afford the investment right now anyway.
    I think you do not need to feel bad for using energy when it is produced, even from a purely environmental point of view. You are still using it for things that would be done anyway so there is no point in fretting over it.

  2. Jazzlet says

    I am jealous, I would love to go solar. Unfortuately we have a chimney shaded east facing simple slope, a north facing simple slope and a complicated and chimney shaded west facing slope (there’s a bay window). So far everyone we have had come and look at it have said “not now, ot unless it gets a lot cheaper” It’s awhie since we’ve had a survey though so I shoud probably try again.

  3. Ice Swimmer says

    Congrats on going solar!

    I’d like to also hear more about the tech stuff. I’ve already guessed what system you’re using (it took one web search to find a supplier’s pages, which present systems which have logos a bit like in the picture and familiar-sounding specs). I’m guessing you have something like 70 m2 solar panels on the roof?

  4. lumipuna says

    Whoa! When the summer comes, you’re gonna need a crypto mining rig to burn all the surplus electricity /s

  5. Ice Swimmer says

    Jazzlet @ 3

    The partial shading (apart from the suboptimal orientation of the slopes) is going to be a problem (as you probably know). It severely degrades the power output of the solar panels. The effects could be mitigated by implementing a system in which each module/panel has their own (micro)inverter (solar inverter is the thing that converts the DC from solar panels to AC while simultaneously taking the maximum power from them). That would prevent the partial shading from sapping the power from the unshaded panels, but it may not be cheap to set up such a system and the efficiency of the system and feasibility of battery storage are a bit iffy. I don’t know what’s available commercially.

  6. Ice Swimmer says

    BTW, the suspected supplier has a job ad in their pages for a testing engineer in Austria and this is what they state:

    “For this position we offer a salary of at least EUR 37.100,00,-- gross per month. Depending on schooling, training and experience, a willingness to overpayment exists.”

    Should I apply for this? 8-)

  7. says

    Hey, when I told you it was mostly Mr’s project, I meant it!
    Now, let me see what I recall about the setup from the one appointment we did together. Ice Swimmer, you’re correct in guessing the Austrian company that made the central components. The solar panels themselves are from LG and one of their advantages is that the whole system is very good at regulating partial shading, for example each panel has two subdivisions that can be regulated independently.
    The central component for “home use” is the DC converter. The solar panels produce DC, but we use AC, and whenever you convert it, you lose energy, just like changing money back and forth between currencies. The battery operates on dc and only converts it to AC when it’s needed. This will be important at a later point in time, when my car needs replacement, because electric cars are fuelled with DC and I would be able to charge it without losing much in the transfer.
    Our home doesn’t have the ideal alignment with one side facing south, but it’s facing southwest with quite a lot of evening sun. Right now I get at least some power until about 5pm and it’s rapidly expanding. Even a rather cloudy day like today will cover the base consumption for fridge, freezer and lights already for most of the day.

    Nah, i won’t beat myself over the head for using the energy in a way that I see fit. I’m also not going to make my life harder, for example by taking over the laundry from Mr just because the sun is shining during the week.

  8. kestrel says

    Congratulations, that’s terrific! I wish we could go solar and i keep looking into it. So far, we just can’t afford it. This is a good place for it though as we get so much sunshine throughout the year. And actually the local co-op has at least some solar panels on the grid. We do have neighbors that have gone solar but all of them have more money than we do… most of these people are retired from the oil industry which is kind of ironic.

  9. says

    Ice Swimmer
    More like 20m2. How big do you think our house is?
    Well, for finance there’s a mix of low interest and high inflation, so we’re basically making money on borrowing it. But yeah, we were lucky in having no financial loss due to the pandemic but actually a lot of “saving” since we’ve been to restaurants for the huge amount of one time and not on a holiday at all.

  10. Ice Swimmer says

    Giliell @ 10

    I was interpreting your statement so that you have a 7.1 kW peak power solar array, which would need 70 m2 (at standard peak solar irradiance of 1 kW/m2) if the efficiency is 10 % (it’s often better nowadays, I’ve never followed solar panels that closely*, I’ve been much more interested in the inverter technology). Some LG panels have a stated efficiency of over 20 %, it seems.

    As for the size of your house, I wasn’t sure, but thought that a big family (for modern times) needs a big house (over 100 m2). On the other hand you have multiple floors, IIRC, so the roof area isn’t relatively speaking that big.

    * = Maybe I should. There’s interesting research that’s happening in my alma mater on this subject. (the video has subtitles)

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