[RE-wrenches] high insolation value and inverter undersizing

[Jason Szumlanski]

I found the latest module "rightsizing" paper by Enphase pretty
interesting. It does stand to reason that there are a lot of hours in the
day where the inverter is producing less than rated power, so increasing
the module size makes sense. Obviously there is an optimum point in every
system where clipping exceeds gains, but that's virtually impossible to
nail down due to so many factors being involved. I think the point would be
that PV mods are coming down in price so much that "rightsizing" is
basically equivalent to "upsizing," within reason, of course. Spending an
extra 25% on PV might increase the installed system cost by 5-10%.

*Jason Szumlanski*

*Fafco Solar
*


On Sun, Jan 27, 2013 at 6:00 PM, Marco Mangelsdorf <marco at pvthawaii.com>wrote:

> I have had a concern for a long time that as PV modules have gone up in
> output that there is inevitably going to be more and more clipping taking
> place as they’re paired with comparatively lower output inverters.  In
> effect, matching, say. a 260-watt module with a micro inverter with a max
> output of 225 watts reduces that 260-watt mod to 225 watts.  It’s not a
> matter of if clipping will take place, but how much and how much actual
> harvestable energy will be lost.****
>
> ** **
>
> Out here in the tropics, even in January with the lower sun angle, we see
> irradiance levels well above 1,000 watts/square meter range.  Take a look
> at what I copied today from a weather station that we installed at nearby
> installation.****
>
> ** **
>
> Given the clipping issue inherent in using undersized inverters, it seems
> to me that moving to larger output micros makes a whole lotta sense.  I’ve
> got one of the first installs using the Power-One 250-watt and 300-watt
> micros and am so far quite impressed.  Why use a 225-watt rated micro with
> a 225-watt or higher output mod when larger micros are now readily
> available?****
>
> ** **
>
> What are the views out there regarding this clipping issue?  Is it as
> minimal as our Enphase friends suggest in their latest white paper or more
> of an issue as I conclude?****
>
> ** **
>
> marco****
>
> ** **
>
> ** **
>
> Environmentals from Weather Station at a Hilo, Hawaii installation****
>
> * *
>
> Sunday, January 27th 2013, 12:40:00 pm****
>
> [image:
> https://easyview.auroravision.net/easyview/images/icons/weather/temp-red.png]
> ****
>
>  ****
>
> *Ambient Temp.* 25.30 °C****
>
> *Cell Temp.* 41.70 °C****
>
>  ****
>
> [image:
> https://easyview.auroravision.net/easyview/images/icons/weather/sun-yellow.png]
> ****
>
>  ****
>
> *Insolation* 127.81 kWh/m²****
>
> *Irradiance** 1,175.00 W/m²*
>
> **
>
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