Author

Topic: Commercial grid-tie solar (Read 526 times)

donator
Activity: 1218
Merit: 1015
May 05, 2015, 06:53:14 AM
#5
Somebody help me before I propose something stupid!
donator
Activity: 1218
Merit: 1015
May 03, 2015, 08:18:24 PM
#4
Bump
donator
Activity: 1218
Merit: 1015
May 03, 2015, 06:48:25 AM
#3
What is the per kw price when compare to traditional power?
With a 50-year simulation, after incentives and since we'd be "locking in" on inflation (so this is in "May, 2015 dollars") - $.0124/kWh in the first set-up (cheap poly panels), $.0125/kWh in the second set-up (presumably more long-lasting mono-si panels and different inverter setup), $.0201/kWh in the third set-up (expensive mono panels with passive sun-tracking mounts). This also assumes the panels can be resold after fifty years for 20% of their original value, which I'm unsure of, and assumes nothing breaks (which I'd price in if I thought I could do reasonably).

The biggest difference compared to how this'd be set up in a residential setting would probably be the loan rate, but some states may have very generous rates for solar projects.
full member
Activity: 211
Merit: 100
May 02, 2015, 11:47:32 PM
#2
What is the per kw price when compare to traditional power?
donator
Activity: 1218
Merit: 1015
May 02, 2015, 05:56:48 PM
#1
We're in Mason, OH (45040). Have ~2000m2 usable roof space. We consume at least 138kWh/yr and this is projected to increase at least 5% (probably closer to 15%) YoY for at least five years. Energy independence isn't a priority -- I only mention it because we wouldn't want to be producing too much electricity.

Duke offers net metering with renewables-generated electricity able to be sold back at the base price we'd buy at ($.0289/kWh). On top of the 30% federal rebate, we'd plan on taking advantage of the 10-year $.023/kWh credit as well as a .71% 20- or 25-year loan.

We currently have a massive Liebert 600T of unknown capacity (the lead-acids are all at end-of-life and basically considered dead - we don't have the UPS switched to output to our outlets, even) which I'd LOVE to see replaced with Tesla UPS units. That said, with the generous renewables-made purchase price of Duke's, I'm assuming batteries are of little use outside its actual UPS use and for load-shifting (Duke does that time-of-day irritation).

Assumptions made from researching some solutions on which I may be wrong (and would love to be corrected on!):
  • We're going to lose a lot of potential electricity in Winter months due to snow and it would be reasonable to forecast it as 50% soilage loss. Without easy access to the roof, we can't even manually clear it off and would thus need to find some kind of active heating solution of which I'm unaware.
  • Tracking systems are great for "work" efficiency, but as far as I've seen, are never cost-effective and generally break way before the panels (which is a huge deal).
  • Poly-si is a reasonable "short-term" (<25 years) solution while mono-si's long-term production output and efficiency makes it attractive in long-term forecasting - BUT mono-si may become an enormous PitA and cause massive losses during Winter months due to strings going down from some panels being partially obstructed. (maybe there's a workaround?)
  • Relatively cheap panels seem to be particularly inefficient when operating below ideal capacity, where that single efficiency % mfgs like to throw around is flat-out misleading.
  • Outside the panels, mounting solution, inverters, tie-in (do Teslas handle this?), and possibly batteries, I can get everything I need at Lowe's and/or Harbor Freight. (and Lowe's even offers some of the stuff I explicitly listed!)
  • It's almost impossible for a solar installation to be NPV- UNLESS it's professionally installed. (our department has free time, so installation is effectively free UNLESS it results in exclusion from federal tax credits, in which case the cheapest option is probably still for us to go get certified and install it ourselves)
  • Some locations require government permits??


Help appreciated. Details certainly available on request! I'm trying to snag actual electricity consumption data, but it's guesstimated for now (giant office kept quite cool in Summer). Here's a .sam going over a few different potential ways we could do this (there's a $10k cost added for mounting and misc. pieces while the additional $5k in labor is for consultations -- the 142.6kWh scenario assumes we buy a truck-load of UTRF-090s): https://www.dropbox.com/s/h65eax719s005c7/TG.sam?dl=0
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