Solar - Experiences/Gathering Information

Discussion in 'General Discussions' started by gsmith22, Apr 29, 2020.

  1. gsmith22

    gsmith22 Member

    As the title indicates, I am looking to install a solar field on my property to offset electric use. It seems like a no brainer in combination with geo (probably without it too). I'm in the gathering information stage and was wondering if there are any gotchas that the experienced folks on this board have run across to be aware of. I have enough open land that I plan to do a ground mounted array and can orient them due south. Some info/questions I have run across:

    1. Green Power Energy is a solar installer near me that has been both recommended to me and has seemingly outstanding reviews online (4.8 on Google with 181 reviews). Anyone have any experience with them that would suggest the hype isn't real?

    2. Field Sizing: We installed geo last fall so I have a full winter's records of electric use but not summer. My summer electric use records will still have the 30 year old A/C electric draw which likely overstates anticipated use with the geo. But, we are very likely going to have a pool installed at some point presumably with a heat pump pool heater. I really don't want to wait a year or more (and have federal tax credit drop 4% or become 0%) to get records of actual usage. How problematic is it to size a field on anticipated use? Electric provider documents seem pretty adamant that I can't have a grid tied system and produce more than I use over a year. Is this because they will cap credits or is there some actual physical/connection issue with it?

    3. Ground mounted arrays - everyone seemingly does roof mounted but I suspect that is because they don't have the land area for ground mounted. I understand ground mounted may be more $ upfront because you have to build the structure that supports the panels (whereas your roof is already there). Are there any downsides to ground mounted? It seems like it would be a much better fit because I can dial in the array tilt and orientation (to the south) and potentially change the tilt where as roof direction and tilt are fixed. Something I am missing? I am assuming the structure to support the array would be included in the federal tax credit (I understand roofing replacement isn't)?

    4. Anyone use batteries with grid tied system? I was thinking this might be a viable option on two fronts - one to power them up during day and then discharge at night ala Tesla powerwall with grid backup to pick up any overuse/undercharge - ie keep as much power produced on site and minimize electric company credits/interaction. But the second part that intrigued me (and potentially more importatnt) was to be able to use the batteries in a power failure instead of having a propane or gas generator backup. I know most grid connected solar fields go dark due to the inverter shutting off when no grid power available. But I don't think that is the case when you have batteries and Tesla's stuff seems to anticipate the use of batteries when grid power is expensive or not present. I tend to favor this arrangement over having a big generator with a bunch or gas or a 500gal propane tank sitting idle for potentially a year between uses. Obviously there are alternatives to Tesla but more interested if anyone has done this and how it has worked out. Would really like to get rid of need for big, idle generator for that once/year or once/2 year power failure.

    Thoughts on my planning?
  2. Deuce

    Deuce Member

    Make sure to use a variable speed pool pump. I switched 2 years ago and my pumping costs are 25% of what they were. If your electric provider will buy back your excess solar energy then I don't see the need economically for batteries. Also I like ground mounted solar but leave room to maintain the grass / weeds around it.
  3. gsmith22

    gsmith22 Member

    having a variable speed pump on my flow center, I can concur that there is no way I would go with single speed anything at any point in the future. matching output to demand is a beautiful thing

    On the battery aspect, I was looking at that more along the lines of replacing a gas/diesel/propane backup generator. we invariably lose power once a year from a tree falling on a line nearby and it never happens at an opportune time (is there one?). in my current situation, i can't power the heat pumps with a backup generator in the winter so its either spend big to get a backup system that just sits there and does nothing, go the battery route, or freeze for three days while the power company figures out what to do. I'm inclined to go the battery route (if its feasible) to avoid freezing (and eliminate the maintenance of another fuel powered engine and need to have fuel tank). But I hear you, if you constantly discharge the batteries at night and recharge the batteries from the solar during the day, it definitely extends the payback on the solar field likely out beyond the panel lifetime. Maybe the most economically viable route is to get the battery system 5 or 6 years in once these systems have matured even more than they are now, prices come down, and my solar field has paid for itself while hoping I don't get a power outage in winter during the timeframe.
  4. Noobie

    Noobie New Member

    We have a ground mounted solar installation, and recently added 32 kWh of batteries (we also lose power due to trees). For complicated “above my pay grade” reasons, we could not use Tesla Powerwalls (my first choice; I have a Tesla vehicle) and went with Sonnen, a German manufacturer.

    Our MA utility net meters, so we use the utility as our battery most of the time, as we generate heaps of power during the summer day. Our batteries can only hold so much, so we’re happy to have the utility net meter and be our additional battery. Check whether you want a “pure” South orientation, as I’ve heard that you can sometimes get better annual production with a somewhat lower peak production by pointing SE. Again, above my pay grade and the ground installation was done by the previous owner.

    It’s early days for us, but we have been really happy with our Series 7, solar, and batteries. We’ve only had short outages, but the geo and batteries kept up nicely. I don’t miss the oil burner.

    The house had a pre-existing 8 kw propane generator which I continue to maintain as part of my “belt AND suspenders” approach . We have not had it wake up from its slumber other than during weekly testing. I don’t think I’d have installed it if it hadn’t already been there.

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