The video on the Bloomberg article on the Solar City pricing provides perspective that it isn't really for individuals and homes.
The potential real demand for it is businesses and utilities shifting some of their use off peak.
http://www.bloomberg.com/news/articles/ ... g-at-5-000
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TOU shifting is certainly desirable. So the question is why does Elon Musk or anyone else think that Li-ion batteries are the right solution for this application (for utility-scale applications)? Perhaps it is, but then why does this unit not include a 480VAC inverter to make it a true three-phase AC battery? Businesses are benefiting today from new PV technology which does power-factor correction (and I believe some of those solutions even work at night), but PV pays for itself even without this feature.
Just to put things into perspective, here is the list of "they suck!" characteristics from Elon Musk's speech:
- Poor integration
- Poor lifetime
- Low efficiency
- Not scalable
- Unattractive (I guess that means they do not come in pretty colors.
But, seriously, does Li-ion REALLY come out on top for large-scale grid applications? I think there are other solutions which are more likely win out for stationary applications. Perhaps Tesla Energy can slot in somewhere between the homeowner and factories and address the needs of small businesses.