One of the biggest uses of residential energy is heating/cooling. Especially in winter months where PV generation is significantly lower (I have seen numbers of

One of the biggest uses of residential energy is heating/cooling. Especially in winter months where PV generation is significantly lower (I have seen numbers of 2-5x summer generation), having "free" heat could be quite valuable. Now, do the economics shake out for storing heat to deliver in winter? No idea, but the idea is not far fetched. Outside of bitcoin mining, there are few uses which can soak up the increasing glut of midday PV generation. Anything that can seasonally store that (even at terrible efficiencies) is valuable. What is going to be the most economic option? No idea. My personal bet is iron-air batteries, but there are a lot of contenders in the space that are competing for widespread adoption.