Link to the article.
Summary: Tesla's Powerwall systems are not intended to get you off the grid. No one with solar _wants_ to get off the grid, because they are selling power to the grid at the same amount they pay to get power from the grid (retail rates, not spot market or some other wholesale price model). This is a Crazy Good Deal that Will Not Last. Take advantage while you can.
Instead, Powerwall is intended as a home battery backup, and should be thought of as a generator replacement. Anyone who has run a generator at a house generally has had to make a choice between (a) something hooked into a gas pipeline, if available, or (b) gas or oil tank, if available or (c) most likely, they have to get jerry cans of gas to put into it, which means trouble when the local gas stations run out (this happened post-Sandy). In Mayberry (<-- not its real name), we had a propane tank and the generator ran off of that, so we had a big generator. Flip a switch and, if everything goes the way it is supposed to, you go about your business as if nothing had gone wrong.
Here in Acton, however, we are on a natural gas line but we are not prone to the kind of week plus outages that Mayberry suffered from during ice storms. Also, we are on town water, so we don't need to run a well pump to get water. We _do_ have to run the furnace blower, so we got a generator after one of the Snowtober events. It is sized to run things like the fridge, a few lights, the furnace blowers. It is _not_ sized to run the clothes dryer, a hair dryer, etc.
"But if its sole purpose is to provide backup power to a home, the juice it offers is but a sip. The model puts out just 2 kilowatts of continuous power, which could be pretty much maxed out by a single vacuum cleaner, hair drier, microwave oven or a clothes iron. The battery isn’t powerful enough to operate a pair of space heaters; an entire home facing a winter power outage would need much more. In sunnier climes, meanwhile, it provides just enough energy to run one or two small window A/C units."
The power output of the Tesla Powerwall is not the issue for a generator replacement. The issue is that during a hypothetical winter storm outage, the short days, heavy cloud cover and possible snow covered panels = poor power generation. You'd need a fair amount of battery capacity to ensure you wouldn't run out before the grid came back online. The paragraph is written with an extremely Not Northeast perspective. We mostly heat (and cook) on gas or oil, so the crucial thing is enough electricity to run the blower motor on the furnace. If you have _that_, you can probably stay in your house. If you don't have that, you probably can't stay in your house. All this vacuuming, hair drying, and clothes ironing is NOT RELEVANT to people who are accustomed to reading about who died this year from carbon monoxide poisoning because they were sitting in the car with the engine running to keep warm because the power was out and they forgot to keep the tail pipe clear/dig the tail pipe out of the snow.
I've been thinking about battery replacement for the generator since before we got the panels. I'd _love_ to do this. It's not quite ready yet, but I feel optimistic that some time in the next decade, we'll be able to ditch the generator in favor of a battery backup scheme.
I don't really expect left coasters to Get It. Snow is weird. But if you are going to critique a product for not satisfying a need, it would be helpful to better understand the need in question.
Bass, of SolarCity, seems to grasp another issue in the generator vs. battery decision. From the article: ""There's a tremendous amount of interest in backup power that's odorless, not noisy and completely clean," he said." No doubt.