[RE-wrenches] smart meters/bidirectional

[Kent Osterberg]

Fellow wrenches,

The programmability of the electronic meters means there are many 
possible measuring modes, even with the same brand and model of meter. 
By "bi-directional", the utility metering folks generally mean that the 
meter separately records energy flowing in and energy flowing out. Net 
is computed by the difference between energy flowing in and out. 
Electronic meters may also be set up to measure "net" energy which 
behaves like the older disk-type meters. Many electronic meters are 
programmed to record energy flow without regard to direction - that 
prevents energy theft that could be accomplished by turning the older 
meters up-side-down. These will count any on-site energy production as 
energy use.

Kent Osterberg
Blue Mountain Solar



August Goers wrote:
> Hi All -
>
> We run into smart meters before we install PV here in CA all the time. The
> smart meter hardware is typically bidirectional in that the arrow on the
> display will indicate which direction power is flowing. I say "typically"
> because there seems to be several meter brands that the utility is using
> and I haven't necessarily verified all of them.
>
> However, in PG&E territory some stage of the software processing doesn't
> seem to register negative kWh readings properly. In other words, if the PV
> system produces more power than used in the billing period then the bills
> get wonky. We've seen bills skyrocket because the negative reading is read
> as a complete reset of the meter which would indicate that nearly 100,000
> kWh were used. That's one reason why it is best to keep the system off
> until official interconnection occurs.
>
> Lastly, I've verified with PG&E that the bidirectional solar meters
> currently used for net metering are the same as the standard smart meters
> but just have different programming. Smart meter programming is not
> currently active for net metered solar clients in the PG&E territory.
> That's a mouthful!
>
> Best,
>
> August
>
> -----Original Message-----
> From: re-wrenches-bounces at lists.re-wrenches.org
> [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Mark Frye
> Sent: Monday, June 13, 2011 8:14 PM
> To: 'RE-wrenches'
> Subject: Re: [RE-wrenches] smart meters/bidirectional
>
> Jay,
>
> I recently ran a smartmeter prior to changing out to a NEMS meter here in
> California (PG&E). <for test purposes only of course>
>
> I saw the energy flow indicator reverese direction and after a period of
> time, the kWH reading also decreased so I was pretty confident that the
> smartmeter was behaving the same as to old dics meters.
>
> Mark Frye
> Berkeley Solar Electric Systems
> 303 Redbud Way
> Nevada City,  CA 95959
> (530) 401-8024
> www.berkeleysolar.com
>
> -----Original Message-----
> From: re-wrenches-bounces at lists.re-wrenches.org
> [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of jay peltz
> Sent: Monday, June 13, 2011 8:10 PM
> To: RE-wrenches
> Subject: [RE-wrenches] smart meters/bidirectional
>
> HI All,
>
> Say are the new California smart meters bi-directional?
>
> A recent install "test" showed the meter resister a negative watt
> indication, but I couldn't run it long enough to see if the KWH went
> backwards.
>
> thanks,
>
> jay
>
> peltz power
>
> _______________________________________________
>
>