[RE-wrenches] Percent of DC capacity that is inverted to AC kWh?

[August Goers]

Hi Chris -

I'd recommend reading through the PVWatts Calculator and manual:
https://pvwatts.nrel.gov/

If you click the help button you'll get to the manual, and you can simulate
a sample system by just entering in a zip code. The default settings
estimate losses at about 14% prior to the inverter efficiency loss.

https://pvwatts.nrel.gov/

[image: image.png]

August
Luminalt


On Wed, Aug 28, 2019 at 6:31 AM Christopher Warfel <
cwarfel at entech-engineering.com> wrote:

> Hi Dan, Sorry for the confusion.
>
> Maybe an example would help.  Take a 2000 w dc multimode system that is
> coupled with a 3600 w ac rated multimode inverter.  What percentage of
> the dc capacity is inverted into ac capacity.  So, roughly 2000 x .9
> (wiring and similar losses from array to battery) x .95 for an assumed
> 5% usage to charge/float the batteries x .98 for dc to ac inverter
> efficiency makes me think that 2000 x .9 x .95 x .98 * (4.5 x 365)
> yields = 2,752 kWh annually. The utility is assuming roughly 3600 x .98
> x (4.5 x 365) {if they are assuming anything at all} = 5,368 kWh revenue
> lost. The regulatory assumption overestimates the capacity factor by @49%.
>
> I'll post to the WRENCHES too to help clarify hopefully.   Chris
>
> On 8/28/2019 9:10 AM, Dan Lepinski, P.E. wrote:
> > OFF-LINE REPLY
> >
> > Hello Chris,
> >
> > The wording of your question is confusing.  You ask about the percentage
> of DC capacity vs AC power output, then add batteries into the mix.
> >
> > What system topology is the focus of your query?
> >
> > I'll be glad to do what I can to assist.  Just need clear direction on
> the configuration.
> >
> >
> > Regards,
> >
> >
> > Dan
> >
> _______________________________________________
> List sponsored by Redwood Alliance
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> www.members.re-wrenches.org
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/attachments/20190828/1498b85f/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 160329 bytes
Desc: not available
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/attachments/20190828/1498b85f/attachment.png>