True that people could go off-grid even with the smallest "cycling" $3500 solution from Tesla. For my home I use less than about 5kWh per day, the only reason it sometimes spikes to 20+ is when I need to do a full recharge of my EV. So a 10kWh unit would be plenty for daily use, only I am not planning to go off-grid, so I can actually store surplus sun energy when I have my panels installed and draw from that "bank" when I charge my EV.
For people on ToU, the unit can make sense even without solar, by simply load-shifting from expensive hours to cheap (nighttime) tariff, even selling back and grid stabilizing could be reasons that you *receive* money (not just a grant) from the utility on a monthly basis for having a utility-interactive home storage. That will depend on the utility and location and design of the total solution - I am getting the impression that the Tesla solution is only a battery backup and BMS, so I would need to read up on whether it expects solar input and needs to feed into the usual inverter that is used for a solar system or what else is required to operate this home battery. Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -----Original Message----- From: EV [mailto:[email protected]] On Behalf Of Ben Goren via EV Sent: Friday, May 01, 2015 9:58 AM To: [email protected]; Electric Vehicle Discussion List Subject: Re: [EVDL] Tesla plugs into new market with home battery system On May 1, 2015, at 9:34 AM, via EV <[email protected]> wrote: > While Lithium batteries make a lot of sense for vehicles where energy density > to weight is a big deal, I'm not sure of the advantage for stationary > installations. Cost for Lithium is still a big issue. An ~40kWh pack of > deep cycle, lead acid batteries that provide battery backup for my house > costs ~$5k. Yes, but how long will those lead cells last? Indications are that, especially when gently used in climate-controlled settings, lithium batteries have the potential to have an usable service life similar to that of a mortgage, but lead acid batteries are notorious for going tits-up after just a few years. If you get five years from $5,000 of lead acid but fifteen years from $14,000 of lithium, the lithium is the better investment. Especially if coupled with a generator or (PH)EV that can serve as a backup for extended periods of low input and high demand, and depending on the size of the PV array, a surprising number of people could drop off the grid with 20 kWh of batteries and many could with 30 kWh. Most should be able to with 40 kWh with many not needing the genset at that point. If you're paying on the order of $15 - $20 / month for grid connection fees, it doesn't make sense to spend $10,000 or so on a battery to drop off the grid. But many utilities are trying to structure their rates such that, even if you're at or over 100% net generating capacity, you'll still cut them a check for $50 - $100 / month...and suddenly, hey-presto, that $10,000 to drop off the grid makes the same kind of financial sense that the initial solar investment did. Things are about to happen fast. Barring apocalyptic scenarios of whatever variety, most of us will live to see the day when a grid connection is as anachronistic as a landline telephone is today. b& -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 801 bytes Desc: Message signed with OpenPGP using GPGMail URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150501/327714c9/attachment.pgp> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
