Posted by: nativeiowan | January 26, 2014

green discussions…

Q:  I read your study and agree it ain’t feasible. I have to ask where the rebate check, or the money they credit you, comes from. If it’s from the utility company I can guarantee they won’t be giving you a great rate, it’d be like cutting their own throat. And I see you list investing 10,435AUD AGAIN after 10 yrs. Do you use old refurbished marine batteries for storage?

A: All good questions… 1) as a double subsidy; the central gov pays part from a budget set up for this, while the state gov pays another part from a budget they set up. We are talking billions of dollars worth of subsidies all up. All paid by the tax payer. In my mind this is a classic re-distribution project where money from one arena (here its supposedly taxes levied on the high carbon producing industries, which in fact means the user/ consumer pays) and is “given” to another, the solar panel manufacturers/ importers (noting all these systems come from China). To my knowledge there is not a solar panel manufacturer in Aus.

B) My system is on a grid so I don’t have batteries. My solar produces power into the grid, I get paid for this, and pay a lower rate for the power I use from the grid. My power source is in fact the grid, I technically do not use the power I produce. Batteries are required for a self sufficient system and are a big “thing”… they are dirty, costly to produce and even more costly to recycle. Standard auto or marine batteries (lead cell or gel cell units) can work but they are not “deep cycle” so they discharge too quickly noting they are made for a burst of cranking power, not a deep, long store of power.

C) Normally  system batteries are  large arrays of heavy 2v to 4V batteries banked up in series. One normally has twice what they require in batteries, so for a 12v system on inverter to AC you’d have 24 volts minimum, two separate systems… A quick search shows a system here selling for:

24V 690AH 6x230AH AGM Deepcycle Battery Bank
Perfect for applications that require either frequent cycling or renewable power storage

D) I have never seen a battery bank last more than a “few” years. Batteries are a large amount of work requiring constant attention and maintenance. Often a simple fault in the system (an over-charge or under-charge) will mean your bank self-discharges, over heats, loses it’s memory, or simply cooks itself into history.  If you consistently discharge your bank (say you watch TV late into the night) your batteries never return to 100% charge. It is easy to “use your batteries up” in a short period of time. And then you are basically shot in the foot. Consider that a few days of overcast weather will mean your batteries get “used up”.

I can think of 3, large-scale applications (Iclarm at Nusatupe, Lola Island Resort, and San Bis resort) I was involved in where the batteries were the bane of existence. All three systems were “given up” as primary sources of power due to the constant and costly failure of batteries. In the 3 applications I was involved in we installed standby diesel generators to act as an auxiliary to charge the batteries when the weather was uncooperative. And once you had the genset installed it became more practical to use that as the primary supply and eventually the solar system became a relic of a once “good” idea.

More later


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