Once the electric cars become readily available, the means to charge them will become a requirement. Once it's a requirement, provision will be made for it.

Several of those off-grid demo houses had less than half their roof area used for photovoltaics. One of them even had a rooftop vegetable and herb garden. That reduces thermal loading, and provides fresh food at least part of the year.

The photovoltaics provide about 2.5 times the average electrical power required per day. That's averaged over light and dark periods. There's always a surplus. The batteries are not 100% efficient. In fact they're quite inefficient. Nevertheless the photovoltaics are sufficient to keep them charged to meet peak demand.

Yes, the technology isn't perfect, AND it's still quite expensive. We just have to wait for the costs to come down. Now, LiIon batteries are much better than their NiCd predecessors. First of all, they tolerate being charged all the time, and they don't mind coughing up considerable power. I don't know what sort of a mix of battery technology their demo houses used, but I imagine it was a mix.

Yes, disposal of defunct batteries will be a burden. However, it's much more manageable than disposal of spent nuclear fuel. Perhaps when 80 million homes have battery disposal burdens it will become more serious. However, there's probably a recycling channel that hasn't yet been explored.

This photovoltaic solution isn't universal, either. As you've pointed out, Terry, as one moves farther toward the poles, the value of photovoltaics is negatively impacted. There are probably other ways of powering homes in those extreme areas. Perhaps the grid distribution method can solve that problem. It will be less of a burden if houses that CAN generate their own power do so, however.

RE