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Re: Controlling the solar scourge



Clark Dorman <dorman@cochlea.bu.edu> wrote:
 
>nick@vu-vlsi.ee.vill.edu (Nick Pine) writes:

>>I like the Air 303. $550 for 375 watts, from Jade Mountain at (800) 442-1972.
>>Now all we need is a cheap, reliable synchronous inverter to feed this tiny
>>power back to the grid. I'm an electrical engineer. I keep telling people
>>that a synchronous inverter at this power level should not cost much more
>>than a lamp dimmer. A simple triac bridge, a backwards lamp dimmer, with a
>>small microprocessor to determine the optimum load for the windmill, $10
>>worth of parts. Someday, someone will design one of these. This is not a
>>very difficult job for the right kind of electrical engineer. Perhaps there
>>is a German product like this already. 
 
>This does not seem to make economic sense.

Better than grid-connected PVs... Much better than filling your house
up with batteries and inverters, if you live near a grid.

>Even assuming that you get 375 watts _all_ the time, then the payback is
>several years.

Not bad...

>You would produce .375 kwh per hour and at $.05 per kwh, it would take you
>29333 hours (3.3 years) to make back the $550.  With down time and realistic
>assumptions, it will be well over 5 years.

Sounds pretty good to me. BTW, my electricity costs about 12 cents/kWh,
and that cost increases with time. I use an average of 600 watts. Steve
Baer uses closer to 60. He would become a net power producer, with one
of these 45" toys on the roof.
 
>Also, connecting power back to the grid is just not that simple.  If nothing
>else, the power company needs to be able to switch the power coming from you
>on and off so they can work on the lines.

Not if your machine can do that itself. It can be just that simple :-)

>And if you want to be paid for your investment, it needs to be meters
>differently.  

False. For instance, in Vermont (I think) state law requires that the
utility let you run a single meter in both directions. And this is
consistent with net billing, and technically, it works fine.

Nick


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