"Wayne.B" wrote in message
...

On Wed, 27 Jun 2012 11:59:03 -0700 (PDT), wrote:

On Wednesday, June 27, 2012 2:05:53 PM UTC-4, Wayne. B wrote:
On Wed, 27 Jun 2012 09:10:22 -0700 (PDT), wrote:

Another problem not addressed is the battery stores and sources DC, but
the power grid is AC. So now we'll have to convert that with big power
stations that take DC and convert it to AC. DC motors turning AC
generators?

===

Absolutely not - high efficiency solid state power inverters.

Being an electronics guy, I thought about inveters... just wondered if you
could scale one up enought to power 200 homes, as he says his ultimate big
battery will do. Assuming 200 amps per house, that's 40,000 amps. That's
one hell of an inverter. And another big heat source, even with the high
efficiency.

=====

There are solid state switching devices that will handle huge amounts
of power with efficiencies in the 90 to 95% range. That's a lot more
efficient than a typical motor-generator set. Of course heat is
related to the amount of conversion loss so higher efficiency means
less heat. I worked in a reserch lab at Cornell University back in
the late 1960s where we had a multi-million watt solid state inverter
for powering the magnet ring of a particle accelerator. The
electronics were not that exotic even then.


-----------------------------------------------------------------------

The power grid has to stay AC. Was the big battle between Edison and Tesla.
The DC was short distance, and the losses were large.