Yeah, that makes sense too. Your article gave me something to think about as I'm planning for my final move in about 2-3 years. We've got two kids and are also caring for ailing in-laws. I mean 20 grand isn't cheap, but what wouldn't you pay to keep your family safe.
My current emergency plan involves lightweight equipment and cooking supplies that would last for about 1 week. However, a flaw in my plans would be energy supply for any medical equipment I would need over time.
Tesla makes some very good equipment. In California, the company I work for is using them to develop a battery power station to enhance grid stability.
Price of these things are coming down constantly. You can always add a Natural Gas generator as well. Which is clean and environmentally friendly. Provided you have space in the backyard and a natural gas connection already