Help with estimating a large renewable energy project

ArcosantiArcosanti Registered Users Posts: 1
First... I am in the "dreaming" phase, so I'm trying to get a handle on some of the "rules of thumb" with respect to the amount of renewable energy would be needed and what the investment cost might look like.

The Dream: Is a dense mixed use community developed in Northern AZ with a goal population of about 1,000 to 1,300 people that is entirely off grid.

I envision something like Arcosanti, Paolo Soleri's dream of urban living - but scaled down (or up depending on your perspective) to something much more manageable in the current day.

By dense, I'm thinking not quite fitting the "tiny home" mantra, but certainly lean, highly efficient and very compact.

The vision is to build 120 condos, and a tract of  80-90 small practical homes comprising a total of about 160,000 to 170,000 sq.ft. live/work space.

On the other half of the property, I envision perhaps 20-30 RV slips and a campground with about 50 to 60 tent spots as phase 1 (but in Phase 2 would be converted to condos and practical homes as we did in the first half phase.

My attempts at the math put the total population near 1,100 people (when both phases are completed)

My desire and goal would be for the entire project to be energy independent. 

Now, I've managed to find a few metrics... one is the consumption of .23 Kwh /sq.ft. and the other suggests a household use of 6,000kwh annually per household (for Hawaii). I also found an article that suggested 1 Mw would power 1000 homes, but then found articles refuting such claims.

But here is where I'm struggling to figure out what the consumption would be for the entire community, and how many acres of solar and wind generators would be needed (and at what cost).  I know it will be up there, and I'm not afraid of big numbers.

Just need some help sorting through these concepts to arrive at some acceptable standards so I can move this idea off the sketch pad and into a draft of a development plan.

Thanks in advance.


  • EstragonEstragon Registered Users Posts: 4,484 ✭✭✭✭✭
    A couple of things to think about before trying to size R.E. for a project like that:

    1. How will heating be done? A solar thermal plant may make sense depending on heating vs cooling degree days, etc.
    2. How will storage be handled? In an off-grid situation, a watt saved is going to be way cheaper than a watt stored. If the community could live with power priced at say 5x the daytime price at night, it might make a big difference in numbers.

    I think the reality is people living in such a community would have to really buy into the concept, and there would have to be pretty punative pricing to make it work. 1000 people is too many to expect community spirit and consensus to work, and not really enough to use grid scale solutions.

    If it helps, a reasonably comfortable off-grid home can get by on ~ 3-5 kw/day (x-heating/AC) with conservation and some load shifting to RE availablility. How that could scale I don't know.
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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