[GreenKeys] How much juice from a solar array?

[Cory Heisterkamp]

This summer I installed a ground-mount 10kW fixed angle array out here at the homestead in NE Iowa and we've been grid-tied since mid-July. During these summer days we do produce more than we consume (of course that'll change come winter). Output has been pretty darn close to the NREL calculator; just punch in an address and add your variables. http://pvwatts.nrel.gov/  

We're running an SMA inverter that I have connected to the local router feeding back real-time data. Today looks like a pretty good solar day: https://www.sunnyportal.com/Templates/PublicPage.aspx?page=6dceaf60-1578-457a-b579-61015f1f4922

And the teletypes don't mind! ; )
-Cory


On Sep 18, 2016, at 4:12 PM, hwhall at compuserve.com wrote:

> A 2011 UC San Diego piece (http://physics.ucsd.edu/do-the-math/2011/09/dont-be-a-pv-efficiency-snob/) comes up with very similar figures (e.g., 0.75 KWH per square meter per day). They also put some numbers into a different scenario: 
> "A typical American home uses 30 kWh of electricity per day, so we’d need 40 square meters of panels. This works out to 430 square feet, or about one sixth the typical American house’s roof (the roof area of a two-car garage)." 
> However, their figures are only for panel output and neglect the storage inefficiencies & conversion inefficiencies if the home is not designed to run straight off the panels.
> 
> Wayne
> WB4OGM
> 
> -----Original Message-----
> From: Jones, Douglas W <douglas-w-jones at uiowa.edu>
> To: tony.podrasky <tony.podrasky at gmail.com>; Green Keys <greenkeys at mailman.qth.net>
> Sent: Sun, Sep 18, 2016 2:35 pm
> Subject: Re: [GreenKeys] How much juice from a solar array?
> 
> From: tony.podrasky [tony.podrasky at gmail.com] Sunday, September 18, 2016 12:13 PM
> > I'd say the parking lot is equal to 2 football fields.
> > Above the entire parking lot are huge solar panels.
> > Does anyone have an idea what kind of power that can
> > generate?
> 
> Guestimate .5 KWH per square meter. per day. Guestinmate a football field at 5000 square meters, This gives one WalMart parking lot worth of solar cells as approximately 5000 KWH per day.
> 
> Given that an average US household uses just under 1000 KWH/month, this is enough to power about 150 houses -- assuming you can figure out how to store the excess daylight power in order to provide power on demand when the sun is down. I guess you need to combine the solar cells with a pumped storage power plant or some such. (Or just focus on ofsetting the air conditioning demand, which is mostly a daytime thing).
> 
> Doug Jones
> jones at cs.uiowa.edu
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