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Re: Wireless transmission of power,

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 03:30 PM 3/17/2005, Tesla list wrote:
Original poster: Yurtle Turtle <yurtle_t@xxxxxxxxx>

Actually, we are involved in a multistate lawsuit
involving several hydroelectric providers over the
value of water in a lake to energy providers. I don't
remember the exact efficiency numbers, as I'm not in
the office today, but I assure you, it's significantly
higher than 10%. In fact, my former boss was involved
in a project which used excess electricity to pump
water into a reservoir to store "energy" then used it
to power turbines when they needed to generate
electricity. So they used hydropower to generate
electricity, which powered pumps, which then again
powered generators. This makes absolutely no sense if
you are losing 90% each iteration.


Typical power plant efficiencies for fuel in to electricity out are around 25-30%, and sometimes better
For you thermodynamics folks out there, steam plants run 1000 psi+ steam at nearly 1000 degrees (F). That gives a Carnot efficiency up in the 60%+ range. Gas turbine plants can be even better because the turbine inlet temp can be a lot hotter... 1400+C rejecting to 300K... that's 82% carnot efficiency, and because the conversion of fuel to heat into the engine is more efficient (no intermediate steam step).

In reality, the prime mover is probably about 60% efficient. The turbogenerator is probably about 90% efficient.

But, as long as oil, coal, and natural gas are cheap, there's really no big reason to push for higher efficiency or alternate power sources or distribution. Let oil get to $400/bbl and coal and gas comparable, and you'll see a real push for efficiency, particularly on the consumer side. Improving your refrigerator efficiency from 50% to 90% not only saves the fuel to produce it, it saves all the thermal losses along the way, as well as infrastructure costs.