Question re: central array with multiple remote connections/loads
My family and I live in East Texas (zip 75707) on a small ranch property. Well, if you’re a major midwestern farmer, then you think we live on a postage stamp. If you call NYC or LA home, then you think we have half a county to ourselves. Despite being only 500 yards from the city limits, our location is electric-only as far as utilities go – no natural gas lines are available. There is a rural water supply, but we have a well on-site and are planning for an additional deeper well to serve a new home (also in planning stages). Propane is an option, but not one I favor for more than my cooktop.I’d like input about building out a grid-tie system, with a twist or two from the “normal” installation. Our ranch has multiple structures which I would like to connect. I have plenty of open / unshaded pasture area for a ground mount array. The problem I perceive is the distance between the pasture and all the structures I would like to connect. Approximate distances are something like this, measured from the proposed array site:
- Existing Barn – 250’
- Planned house – 700’
- Existing house – 1200’
- Shop – 1000’
(Note - existing house and shop are near one another, say 200' apart. Planned house and existing barn are probably 500-600’ from one another.)We’d be looking at what I’d call a “large residential” array – probably in the 30kw range. The question is, can we build a single large array, and not have to do a smaller grid-tie system at each location? From what little I know about electrical stuff, there’s a serious voltage-drop problem over some of those distances, even if you’re using the right wire and running 240v. So finally I get to my question: what about installing a step-up transformer at the central array site, and step-down transformers at each structure?
I have no idea what the cost looks like, if the idea is even technically feasible. Cost is not the only factor, though; avoiding multiple inverter systems and having panels installed everywhere would sure be preferable. Additionally, the cost of bringing in utility company primary lines and transformers to two or three locations is obviously far higher than bringing in a single line to the central array. The last time I checked, bringing in primary was $8-10 per foot, and none of my structures is closer than 600’ from the lines at the road. In my mind, as long as it’s to code and safe, there really is no reason for the power company to have any idea what I am doing beyond the meter they set. (Also, there is no permitting or review required in my area, being outside of city limits.)
Now…just to add one more variable, I also have a diesel-driven 24kw generator, and what amounts to an unlimited fuel supply. I realize that grid-tying a system with a generator presents unique issues. However, power here can be intermittent at times, and the ability to disconnect from the grid and run off of solar and generator power would be very desirable. I know most grid-tie installations do not have solar power available when the grid goes down, but I think that can be worked around. It’s easy not to backfeed the grid using a transfer switch, but I believe that only certain inverters are set up not to backfeed a genset. Thoughts on this would be appreciated.
How’s that for a ridiculous first post? I do appreciate you reading it, and the time anyone might take to chime in with input or responses to these issues. Thanks very much.