Some unwelcome good news

The announcement by Tesla of a new home battery storage system, called Powerwall, costing $3500 for 10KwH of storage, has been greeted with enthusiasm, but also a good deal of scepticism regarding its commercial viability, which depends in any given market on such things as the gap between retail electricity prices feed-in tariffs for solar PV.
This is missing the forest for the trees, however. Assuming the Tesla system comes anywhere near meeting its announced specifications, and noting that electric cars are also on the market from Tesla and others, we now have just about everything we need for a technological fix for climate change, based on a combination of renewable energy and energy efficiency, at a cost that’s a small fraction of global income (and hence a small fraction of national income for any country) . 
That’s something hardly anyone expected (certainly not me) a decade ago...