Fw: Fw: Peeved at the pump

From: Innovatia <dennis@innovatia.com>
Date: Tue May 18 2004 - 12:02:39 EDT

Al Koop replied:

> It sure would be nice to be able to store a day's (or
> preferably more) worth of electricity in some device for later use.
> This would allow us to store energy as well from intermittent sources
> like wind, solar and tides and also just from electrical-generating
> plants at night when demand is low. If we had the capablitity of doing
> that economically now, it seems like we would already be doing that.

With advances in state-change materials, which store energy in the phase
change from solid to liquid, high energy-density storage is on the horizon.
Even at this time, it is better than batteries.The problem is converting
relatively low-temperature heat to electricity. But that is the point of the
new converson devices.

> I conclude that solving this problem must be difficult and maybe even
> impossible. What is worrisome is that with all of these alternative
> energy sources that have some promise, it is not obvious that we will
> have these economically functional when fossil fuels are depleting since
> they may well be difficult to develop also.

My instinct, like Glenn Morton, is to be somewhat pessimistic about the
energy future, though, as my review suggested, there is no reason to be from
a technical standpoint. In other words, the human race is not facing a dead
end technologically, without any alternatives beyond oil. I am convinced
that the primary threat is socio-political, not technical. As the situation
worsens this decade, the masses will be increasingly compliant with the
notion of allowing tyrant-savior-wanabes take over the world.

> So how good are your solar-thermal devices, or how good could you
> reasonably expect them to be in a few years? Is it possible now or
> sometime in the near future to store a day's worth of power in a home to
> run the lights, refrigerator. furnace, plus one other appliance at the
> same time? How much space would the device take? How much would it
> cost? What would its maintenence costs be? How long would it last?

For a typical somewhat-energy-conscious residence (500 W average power use),
a 2 cubic meter tank insulated with the common R-20 insulation would last,
with the existing thermoelectric modules, for about 3 days (as I recall
without referring to my working paper on this), assuming the fluid has the
heat capacity of water. However, with state-change materials, the time can
be doubled or tripled.

> Petroleum products are so convenient because you can store a lot of
> energy in a small amount of space and utilize the stored energy
> gradually in a somewhat efficient manner whenever you wish. It is not
> clear to me that we are very close to duplicating those properties in
> alternative energy sources.

Yes, besides nuclear, chemical energy storage is the most dense. Hence the
prospects of the ethanol economy.

Dennis Feucht
Received on Tue May 18 12:40:29 2004

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