Batteries are here?

Yesterday Elon Musk, one of the tech world’s most famous serial entrepreneurs announced his much-anticipated battery pack solution for residential and industrial use.

You can watch the announcement (complete with poor presentation skills, which is amazing in such a famous public persona) here:

and you can buy (pre-order) the product here.

So am I getting in line?

Not really. Musk correctly notes that solar energy is available only at night, but that’s not the only imbalance: the picture below shows how my energy balance would look like over a year.

First of all, since I consume about 76,000 kWh per year (the red consumption line is actual 2014 figures – of course it depends heavily on the temperature profile of each year), if I was to get off the grid given there are about 1,100 hrs of “useful sunshine” where I live, I would need to increase my solar array to over 70 kW from the current 15 (the blue line):

The green line represents the charge accumulated in the batteries during the summer and depleted during the winter: as you can see, the charge peaks at around 17,000 kWh in November.

At $3,500 for 10 kWh, the cost of batteries alone comes at almost $7M dwarfing the additional 250k I’d need to invest to expand the solar array assuming somehow I could ignore the law-imposed limit of 20 kW and the fact that I have run out of roof. The bigger the summer / winter swing, the larger the batteries must be, to accumulate enough energy to see me through the cold season.

The saving on my energy bill is of around 85%, or €7,400 – not bad, but it would still take me almost 960 years to get even, and I do not plan THAT far in advance!

So is this vaporware?

I don’t think so, but it makes sense only in places that do no experience big temperature swings and in modern houses where consumption has been greatly reduced through other kinds of insulating measures.

3 thoughts on “Batteries are here?

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