On 27/12/16 19:32, Another Dave wrote:
On 27/12/16 15:12, tim... wrote:

For example, there are supposed to be some new battery technologies that
are a couple of orders of magnitude better than currently available.


It depends what you mean by "better". A lead-acid battery (invented 150
years ago) can return between 60% and 90% of the energy you put into it,
so you can only make something a few percent better.

The improvements people are talking about are weight and volume
reductions for a given energy capacity which is irrelevant to storing
mains type energy levels but IS relevant to, say, electric cars and
mobile phones which have to carry their energy with them.

Even so, talking about "orders of magnitude" is nonsense. Lead is dense
but it's not THAT dense.

best energy density is lithium.We are already quite close to the
lightest lithium in batteries possible. Lithium air is potentially
almost a order better BUT the technology is awful. Its almost as hard as
building a fusion reactor.


Another Dave