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[aprssig] Shack backup power

KBØNLY kb0nly at mchsi.com
Mon Sep 12 01:01:13 UTC 2011


Yes, grid tie is dependent on the grid itself, grid power goes down the inverter shuts down to avoid backfeeding the grid.  The only solar system that works when the grid is down is multi mega thousand dollar systems with battery banks and big inverters.

73,

Scott KBØNLY




From: r gilson 
Sent: Sunday, September 11, 2011 7:54 PM
To: TAPR APRS Mailing List 
Cc: solarDIY at yahoogroups.com 
Subject: Re: [aprssig] Shack backup power

      Thought I read some where that you needed the grid in order for a grid tie solar system to work?  Does a solar system work well when the grid is down?  Tnx
      Ron

      --- On Sun, 9/11/11, Bob Bruninga <bruninga at usna.edu> wrote:


        From: Bob Bruninga <bruninga at usna.edu>
        Subject: Re: [aprssig] Shack backup power
        To: "TAPR APRS Mailing List" <aprssig at tapr.org>
        Cc: solarDIY at yahoogroups.com
        Date: Sunday, September 11, 2011, 8:37 PM


        > Where are you buying solar that cheap??  
        > Last I priced it, about two months ago, 
        > it was something on the order of $3 per 
        > watt, I don't see where you're coming up 
        > with $.07 per kWh...

        I found it hard to believe too, but the StarCity ads on the radio around here are saying you can install solar for LESS than you are paying now to the utility, and we are paying 10 cents (unburdened), more like 15 cents with all charges thrown in to the utility.

        These quotes are for "leased" systems.  you sign up for 20 years of electricity at something like 7.5cents per KWH and they install the grid-tie system on the roof of your house.  THey own it, and you are fixed at 7.5 cents for the 20 year life of the lease.  

        [I have not seen this figure directly, but one of the email responses to this thread quoted his costs of 7.5 cents per KWH for a leased system. But I cnnot now find his email.]

        The leasing companies are betting the cost of electricity goes up, and the amortized cost of the solar panels will be less than the increasing coal rates and since they keep the difference, it is a good business model.

        The problem is most people do not think about the time-value of money.  And only think in terms of month-to-month bills.  Investing in a solar array is still a large upfront cost.  But it is like buying a house with a 20 year mortgage.  You will pay less for the house overall than you would ever pay if you rented it for 20 years.

        Investing in solar panels is the same thing as buyihg a house.  Staying with the utilities is like renting for life.

        This new lease solar system lets people avoid the up front investment, and it still gives them the lower total costs, but the leasor who DID make the investment also makes money.

        I paid up front for my system, but since the pay back is now down to less than 7 years, by the time 20 years rolls around, my 20 years of free electricity will have saved TRIPLE the upfront cost.

        Here are the three options:

        People who lease solar will get 7.5 cent electricty for 20 years... 

        People who buy solar, will get free electricity for life which in seven years or so completely pays back the investment and then it is free for life..  A huge payback.

        And those who do nothing, will face 20 years of escalating energy costs and be paying probably 4 times more over the same period.

        Something like that.

        Bob, Wb4APR

        >
        >-----Original Message----- 
        >From: Bob Bruninga
        >Sent: Sunday, September 11, 2011 6:21 PM
        >To: TAPR APRS Mailing List
        >Subject: Re: [aprssig] Shack backup power
        >
        >> To me [solar]’s a good gimmick to reduce the
        >> electrical consumption of an average american
        >> home, but until the cost of solar comes down
        >> from absurd I will stick with my $.075 per kWh
        >> grid power and a generator for backup.
        >
        >You might want to update your assumptions.  Solar around here is already 
        >down to 7 cents per KWH.
        >
        >> We had hail large enough to punch dents deep
        >> enough in steel roofing to cause it to
        >> crack, a solar cell wouldn't stand a chance.
        >
        >Wow, that is a bummer.  Can't survive that.  But the home solar panels now 
        >are all guaranteed to withstand up-to golf-ball sized hail.  They are 
        >something like 3/16ths tempered glass.
        >
        >So if the hail did not break skylights, then solar panels might have 
        >survived.
        >
        >
        >Bob, WB4APR
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