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Number crunching

Discussion in 'Fred's House of Pancakes' started by Leadfoot J. McCoalroller, Apr 22, 2022.

  1. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Heey, congrats! welcome to the club.

    Ours is finally done, they debugged the last inverter string, finished a few minor details, cleaned up the yard and all.

    And just in the nick of time; I'm on my summer work tour and won't have a chance to really do anything at home until approximately Labor Day.

    So it's nice to look on the phone app and see the numbers counting up. I can already see that we are going to slightly miss the original production estimate, and I can also see why: one particular limb of a tree is throwing a little more shade than we anticipated. A fall project.
     
  2. Salamander_King

    Salamander_King Senior Member

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    Yeah, I had a few arborists give me a price on cutting down mature red maple tree on the SouthWest side of the roof. It is large enough such that during the growing season with foliage, it casts a shade on the corner of the roof. The garden is in full bloom right now, I am going to wait for the off-season to cut this tree down. Too large and too close to the house to DIY the felling. Hate to cut down healthy productive trees, especially paying a large sum of money.
     
    #402 Salamander_King, Jun 23, 2024
    Last edited: Jun 23, 2024
  3. Louis19

    Louis19 Active Member

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    I sincerely wish you the best of luck in your project
    I will follow your aventure in this thread
    Cheers
     
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  4. Salamander_King

    Salamander_King Senior Member

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    The thing is, I have already established that solar panel is not the best investment in terms of ROI. And since it is a grid-tied system, even if I achieve the net zero generation, I am not energy independent. If our electricity rate is not double the US national average, or our monthly consumption is lower, then the solar panels would make very little sense economically. But, with my current projection, I should be able to break even within a reasonable time frame, or sooner if the electricity rate keeps going up as it has been in the last few years.

    At least, I am not paying any interest on solar financing. Or pay a monthly fee (equivalent to or slightly less than what I pay now to the utility) for the next 25 years on a solar power purchase agreement. I will own the system once installed. I just hope the system will perform as promised, and I will to able to save money in the long run. I will never get the satisfaction of being self-sufficient, but at least I can say I am contributing my share of green energy from our roof. The only thing is that I am likely causing an increase in the electricity rate which ratepayers are going to have to pay for. The current system is only helpful for those with resources. Those without resources are the ones who pay the most.

    I still want to build a tiny house for my retirement and live off-grid, but that requires much more commitment and determination to change my current lifestyle. Not sure if that works with my other half.
     
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  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    It wasn't so great for my parents.

    They inherited a little place on the beach that was never on the grid. I helped my dad install an offgrid solar power system, which has been expanded and tweaked several times over the past 37 years.

    The place always had some nice charm and some wonderful perks, but the severe limits of electrical availability was definitely a burden. I know my mother did not enjoy being there in her final years. Dad liked it more, and he wants me to take him back there sometime this summer, but even he is coming around to realize that it isn't very easy to deal with.

    I'd love to be able to say "oh, this stuff is cheaper/better now in modern times, I'll have a much better go at it than the previous generation," but enough other things have also changed that I'm not so certain it would hold true.


    EDIT adding:

    Keep in mind you've added a lot to the value of the current house, and younger buyers are going to value this upgrade more than others. Between that and the (currently very reasonable) expectation that retail electric prices are going to keep going up, you're likely to see some greater upside further along.
     
    #405 Leadfoot J. McCoalroller, Jun 23, 2024
    Last edited: Jun 23, 2024
  6. Salamander_King

    Salamander_King Senior Member

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    No doubt. We all lived our lives with constant lifestyle creep. Not many of us are willing to give up the convenience of always-on electricity. But if I am 20 years younger, and if my significant other is willing to endure the lifestyle of homesteaders, then I am certainly willing to give up the convenience of modern-day technologies. But it becomes only difficult or impossible as we age.
     
  7. Salamander_King

    Salamander_King Senior Member

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    Yeah, I've heard this line of thought, mostly as a "win-win" marketing catchphrase from solar companies. But, I largely dismiss it. It is very similar to any realtor saying certain remodeling adds "value" to the home. If the house is unaffordable for most young people now, how does adding more value to the home by installing solar panels thus increasing the sales price of the home make it more attractive to them? At best, if I try to sell my house at the same price as the other similar houses without solar in our area, then yes, our house is more marketable. But planning to recoup the installation cost of the solar 10-20 years later when we try to sell the house is wishful thinking, IMHO.
     
  8. Salamander_King

    Salamander_King Senior Member

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    Well. My application for the Level 1 PV Interconnection- Screening Results just came back. It was determined that I will need a transformer and cable upgrade in order to proceed with the project much like what @Leadfoot J. McCoalroller had experienced with his system. At least, it was not out right turn down of the application. But the cost of the upgrade to be determined and a big caveat is that there is a long lead time equipment notice for this upgrade to take place. Even if they quickly determine the cost and I pay for it to order the equipment needed, the ETA is anywhere from 6-12 months.

    All likelihood, the project will not be completed this year as I wished. It is more like sometime next year at the earliest. This really changes the planning for the project. I am hoping the installer will honer the quote they gave me and install the system at the agreed upon price next year... But that all depends on the added cost of the transformer by the utility.
     
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  9. Salamander_King

    Salamander_King Senior Member

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    Well, as soon as our utility gave a conditional OK, that is transformer needs to be upgraded before energizing the system but otherwise the project is approved, my solar company sent be a bill for the project to order the equipment. I paid cash promptly. And 2 weeks later the 35x 420w panels, micro inverter, rack system, and other materials are delivered. They will be installing on the main house roof tomorrow. As soon as roofer finish the roofing the garage, it's roof top installation will follow. Then the electrician will come to upgrade the main service panel and connect the system.

    Even though the system will not be operational for months, it probably is a good thing since the solar panels price went up at the beginning of this month due to the new tariff taking an effect on Chinese solar cells. The 50% increase in Made in China solar cells. Mine is made in USA panel by Korean based Qcell, but China having the world 80%+ market share on solar panel, I know even the US made solar panel must have gone up on the price after the tariff went into an effect. My panel was quoted in May this year price.
     
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  10. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Last day of summer #1 harvesting sunlight, so it seemed like time for an update.

    We hit Kilobuck Day in late August- that is to say, the day that our system crossed the threshold of producing $1,000.00 worth of electricity.

    With the recent weather we are banking up quite a lot of sunlight with nearly zero power used on heat or air conditioning. We'll need it all for heat when winter rolls around.

    One quarter of the array dropped offline around the 1st of September. I've been traveling so much that I didn't even notice it until my installer called me and asked if he could come over to fix it. That's right, he was reviewing it remotely and noticed the failure before I did. I love that service!

    The lawn eventually grew back around the construction site, and now we are picking out some trees and bushes to plant around the North side of the array to make it look prettier.
     
  11. vvillovv

    vvillovv Senior Member

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    how is your local utility pricing a kW of electric and what's the size of the array? I'm looking at roughly 9 kW of space on our roof, but the best year round sun exposure is right in front of our detached garage around 50' from the house. The more data I can collect especially in our area (NorthEast) the closer I can get to making an informed decision regarding size and location of panels, inverter(s), etc. :cautious: Been tacking summer gas and electric usage along with weather, hoping to see some patterns develop.
     
  12. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    15kW nameplate rating.

    Power is $0.1735 per kWh whether I'm buying or selling 24x7. This detail of your local net metering law is probably the biggest/firstest thing to determine, it will guide many other decisions along the way.

    Go play with NREL's PVWatts website. Heck of an education, it was very useful when we planned ours.
     
  13. TMR-JWAP

    TMR-JWAP Senior Member

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    Very grateful I'm still being hit for only 11ish cents per kwh. 5-6 years from now when I'm looking at roof replacement, it will be interesting to see what's available for solar. How big of a system would be needed if my average monthly use is ~3000kwh?
     
  14. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Lots of variables. Just a few:
    • Needed for what exactly? I gather you want to do a net-zero; a total offset of all electric usage. But be aware that there are other useful design strategies. My system is built the way it is largely because of the way the Commonwealth of Pennsylvania wrote its net metering law. If the law had been written a different way, a different design goal might've made more sense. Find out what the law is where you are because that is going to steer everything else. Can't stress that enough.
    • Weather at your location- how much sunlight do you really get where you are?
    • Pitch and azimuth of your roof- solar panels need to face the sun to work best. With ground mounted panels, you control both angles so it is easy to optimize. When you mount on the roof of an existing structure, you're more limited in terms of optimizing angles and thus more panels are needed to hit the same annual gross output.
    • Shadows from buildings and trees through all seasons

    So to properly calculate what you want to figure out, start with 3,000 x 12 months = 36,000 kWh annual demand. Then you can start modeling different system configurations until you have something that can deliver that much.

    That PVWatts website I mentioned above can help you significantly with modeling various systems once you get some idea of what makes sense for your local laws.

    I was looking at electric prices as "something likely to go up" even before everyone went wild on A.I. I'm now anticipating substantial power price increases within the service lifetime of my system. Have your own think on that topic and see where it leads you.
     
  15. fuzzy1

    fuzzy1 Senior Member

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    Yikes, that is huge.

    My all-electric home started at about 10,600 kWh/year, later exceeding 11,000 a few times. But through a variety of conservation means and energy upgrades, I slashed that to 5,000 per year. Then built the solar system over two years to produce about 6,000 per year, to allow some margin for system aging, growth of neighboring shade trees, and weather variations. Though it didn't take long for conservation laziness and some new devices to push consumption up close to that 6,000 figure.

    Without most of those conservation and energy upgrades, a net-zero solar system would have exceeded the size of our prime south-facing roof area, with additional panels needing to be placed in non-prime lower-production east and west exposures. With that past conservation, there is enough prime south area remaining to take an expansion to cover our new plug-in hybrid.

    My system is somewhat impaired by partial shade from neighbor's trees, and from the Pacific Northwest's lousy winter overcast. NREL's PVWatts calculator -- an older version than is available now -- did a reasonable job in predicting average annual production, after I threw in an ad hoc adjustment factor for the tree shade. It also helped me understand that my non-ideal roof pitch didn't matter much, costing only a few percent in annual production, not enough to bother considering mounting at a different panel tilt than the natural roof slope.
     
  16. Salamander_King

    Salamander_King Senior Member

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    The average Electricity consumption in U.S. homes varies by region and type of home. In addition, what electricity is used in the household and how many occupant lives in the home makes huge differences. Can't really make an apple-to-apple comparison between someone living alone in an efficient apartment complex building North East to someone living in the south, in large single-family detached home with 6 people.

    Electricity use in homes - U.S. Energy Information Administration (EIA)
    upload_2024-9-23_7-31-50.png

    Everyone's situation is unique depending on where you live, what type of dwelling you live, how many family member live there, what life style you choose to live, etc. You just have to do your own math. There isn't one formula that works for all.

    After variety of cost and energy cutting efforts over the last 10 years, we established that we use ~10,500kWh/mo of electricity in our home. This number to be very consistent and manageable without breaking our bank or changing our lifestyle drastically. Incidentally, 10,500kWh/mo of electricity consumption is right at the average US household monthly electric consumption. If our electricity rate is $0.17/kWh and stays at that price, the solar panel would have made no financial sense. The payback period is ~25 years without incentive. Even with full 30% off by tax break, it still takes ~18 years to pay back the initial cost. That is way too long.

    But with our current $0.32/kWh electric rate and anticipated ~4% hike every year, and with taking a full advantage of tax incentives, we can break-even in less than 7 years. That makes good economic sense to me. But if the electric rate falls before $0.20/kWh in the near future, although very unlikely in our current political climate, I will regret taking out a huge chunk of our retirement fund to install the 14kW solar system on our roof this year. There is a risk and benefit in everyone's situation.
     
    #416 Salamander_King, Sep 23, 2024 at 7:58 AM
    Last edited: Sep 23, 2024 at 9:29 AM
  17. Mr.Vanvandenburg

    Mr.Vanvandenburg Senior Member

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    There are cities and towns that wouldn’t allow that tree removal without a permit and approval. There would have to be some very important reasons and a professionally documented report backing them up. My town has it and it’s out of touch with reality.
     
  18. Salamander_King

    Salamander_King Senior Member

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    Each municipality is different. We lived in a city a long time ago where a town police would stop by to give us a warning to remove 8 feet spruce tree that was dying. Not because of the fire hazard or anything, but for the aesthetics. Yep, the ordinance says to remove dead trees which is considered an eyesore or you are fined.

    BTW, I ended up getting help from family, friends, and volunteers and DIY felled, limbed, bucked, and removed ~24 mature maple trees around our house and back woods. All in all, over 20 tons of logs. It took ~10 days to finish the work with average 2-3 people working on site daily. We had a wonderful volunteer group in our area who operate firewood bank to give away cord wood for heating homes of unfortunate peoples. This work was mainly for the solar panel system on our rooftop but I took the opportunity to trim down the thick wooded area with some over grown dangerous trees to open up the area to be used for more gardening. If I hired a commercial tree service to do the same job, it would have cost me well over $10K. But DIY cost was $0, except a cost of a new powerful felling chainsaw at $1,700 and ~6 gal of ethanol free gasoline fuel and 3 gal of chain oil cost. Money well worth spent.

    upload_2024-9-23_9-47-19.png
     

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  19. John321

    John321 Senior Member

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    That is an important point and well stated for individuals who do proper Return on Investment calculations on large projects.

    Our particular area of the country may be forced to create new energy sources by the political climate which will make our $.09Kwh skyrocket to unpredictable levels.

    If common sense prevails and gradual transitions are made then rates will slowly stabilize to reasonable values.

    Making any type of ROI calculations in that type of dramatic energy climate borders on a fools folly.

    Another somewhat 'politically' charged variable is an individual states net metering laws. They can as mentioned have a large impact on system payback length.

    As if that wasn't enough uncertainty, both the 'political climate' for green energy as well as net metering laws can change on a dime based on current elected officials whims. That is happening now much to the dismay of many new solar generating systems owners, and it is not really fair to those individuals.

    I agree wholeheartedly that the area of the country you live in and your individual situation is unique and requires careful thought before jumping in.

    In other situations and areas like California and parts of the Northeast US going solar can be a no brainer positive ROI - not so much in other areas.

    Net Metering 3.0 Rules Create Chaos In Rooftop Solar Market In California - CleanTechnica

    Arizona's Net Billing Battle: What You Need to Know | Solar.com

    Idaho ends net metering, shifts instead to net-billing system for solar compensation (solarpowerworldonline.com)

    Most and Least Friendly States for Solar Energy (2022 Report) (2024) | Today's Homeowner (todayshomeowner.com)

    I would very much like to have a self sufficient solar generating system for our home and think it is admirable for people who do that but due to our geographic area - pricing conditions- current laws -lack of net metering- potential for change to most of this it makes no economic sense in our area.
    .
    I enjoy this thread a great deal and especially hearing about the op's success in installing his system and the benefits he is getting from it. It is inspiring to hear about individuals who have been successful in supplying their own power and meeting their own needs.
     
    #419 John321, Sep 23, 2024 at 10:18 AM
    Last edited: Sep 23, 2024 at 10:44 AM