Oh and to complete the answer to the issue: Best way to solve this is de-centralized battery storage in the endpoints where the PV is installed to soak up the midday peak and release it when the home or the EV charger needs it. And of course, avoiding the local low voltage to be configured "hot" accommodating overload, because that will reduce the amount of local generation it can allow. It is a pretty basic case of resistance, current and safety limits in the inverter (=generator). Cor.
On Thu, Sep 2, 2021 at 5:17 PM Cor van de Water <cor.vandewa...@gmail.com> wrote: > > The ways that the grid can't handle the amount of PV generation is > typically not on national grid scale or even regional grid, although > that may theoretically happen when the transmission line capacity is > reached. > Most likely is a problem on local scale, where you have pole pigs > (25kW) serving blocks of houses which can create an overload on the > pole pig when all houses airco's.kick on, so a utility tends to set > the output voltage of the pole pig a little "hot", say 245V instead of > 240 to account for the expected (over)load. > Now assume a mild and sunny day after 3 of the homes have had PV > installed to compensate for their pool heater or their EV charging. > However, if not much load is present and all PV systems crank out > between 5 and 10kW then the opposite overload problem happens: the > pole pig struggles to feed all that PV power back into the Mid Voltage > (usually 11-22kV) line. > Buuut - the low voltage was already a little "hot" to account for the > overload situation, so when now the PV is cranking away, the voltage > drifts up and up and reaches the limit that the "anti-islanding" > protection is set to, so the PV either cuts out completely or > throttles back from the overload voltage, whatever it is set to: 250V > or 255 or even the max permissible on a low voltage grid 264V (240V > +10%). This is the most likely reason that PV will cut back, simply > bottlenecks in the local grid, causing the inverter to run into its > safety limits and cutting back to avoid overvoltage in the home. > Cor. > > On Thu, Sep 2, 2021 at 5:03 PM Michael Ross via EV <ev@lists.evdl.org> wrote: > > > > In today's local paper is an article about FlexGen in Durham NC, they're > > raised $150M. They build "software that helps grids manage energy storage." > > > > Doesn't sound exactly like market and also not hardware management > > software. " FlexGen's energy storage solutions bridge the gap of > > reliability for the grid, and help accelerate the adoption of renewables by > > shifting renewable power to times when it is needed the most." > > > > Source is the Raleigh News and Observer. Thursday 9.02.21 page 6A. I get > > this in paper form, but there is an online version. > > > > On Tue, Aug 31, 2021, 8:30 PM EVDL Administrator via EV <ev@lists.evdl.org> > > wrote: > > > > > From what I've read, California now has so many PV installations that > > > they're actually deliberately cutting output - there's more supply than > > > demand. Springtime is a particular problem because there's ample > > > sunshine, > > > but the weather is mild, so there's little need for heating or aircon. > > > > > > Long-term storage would seem to be the real answer, I guess (I"m not an > > > expert), and maybe the legislature needs to revisit their RE goals. > > > > > > But for the immediate situation, more EVs => more demand => more efficient > > > use of installed PV, no? > > > > > > Since charging tends to be at night, short-term storage would be a factor, > > > I > > > suppose. Seems easier to implement than long-term storage, but again, > > > what > > > do I know? > > > > > > David Roden, EVDL moderator & general lackey > > > > > > To reach me, don't reply to this message; I won't get it. Use my > > > offlist address here : http://evdl.org/help/index.html#supt > > > > > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > If at first you don't succeed, skydiving probably isn't for you. > > > > > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > > > > _______________________________________________ > > > Address messages to ev@lists.evdl.org > > > No other addresses in TO and CC fields > > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > > ARCHIVE: http://www.evdl.org/archive/ > > > LIST INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > > > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: > > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20210902/c9d37f11/attachment.html> > > _______________________________________________ > > Address messages to ev@lists.evdl.org > > No other addresses in TO and CC fields > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > ARCHIVE: http://www.evdl.org/archive/ > > LIST INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org _______________________________________________ Address messages to ev@lists.evdl.org No other addresses in TO and CC fields UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/ LIST INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org
