Re: what is subtle energy and how can it be harnessed and used?

Ah, yes... Nikola Tesla.  He is one of the few electrical engineers to
capture the public imagination, with his promises of free power from the
atmosphere, anti-gravity, death rays, etc.  In truth, he was a brilliant
engineer, who, along with Charles Proteus Steinmetz was a driving force in
the development of AC power generators, transformers, and motors that
enable the widespread adoption of cheap, useful electric power.  He
was also a flamboyant showman (if "Dilbert" is the stereotypical
engineer, then Tesla was the "anti-Dilbert").

But I digress...

I've never run across reference to "subtle energy", but then again, I'm
not a great student of Tesla.  From what I do know about Tesla's work, many 
of his inventions (such as the famous "Tesla coil") involved not just 
alternating current but clever arrangement of resonating circuits operating 
at high frequencies.  That makes it sound to me that this "subtle energy" 
may be what we now would call radio energy, or electromagnetic waves.  
There is some debate whether Tesla actually preceded Marconi in the 
demonstration of practical radio transmission (based on the theories of 
Maxwell and the experimental proof for EM wave propagation by Hertz).

By the way, radio transmissions indeed are a way to transmit power at a 
distance without wires; the trouble is that it's very difficult to
transmit a lot of power efficiently at long distances.  At short distances, 
your microwave oven heats food via radio waves (i.e., power is transferred 
from a radio antenna to the food). The power transfer is on the order of 
100s of watts. The efficiency is good because the oven's transmitter power 
is confined within the oven's cavity. (A microwave oven actually uses a 
a radio transmitter not unlike those found in radar systems... hence the 
name "Radar Range" trademarked by Amana). At long distances, an ordinary 
radio, TV, or cell phone picks up energy from a transmitter from a few to 
hundreds of miles away; this power transfer is on the order of microwatts 
(millionths of a watt)... that's not quite enough to cook a hot dog :-)
Even though the transmitters are blasting out as much to thousands times 
more power than a microwave oven transmitter, the power transfer efficiency 
is poor because the transmitter's power is spreading out in all directions, 
and only a bit is intercepted by your reception antenna.

There are a zillion Web pages out there related to Nikola Tesla; I won't 
repeat these here, as any search engine will easily get you pointed at 
them.  Some offer plans (or even kits) to build Tesla coils.  I want to
caution you that experimenting with these can be extremely dangerous to 
life, limb, and property.  Exceptionally high voltages (on the scale of 
those found in high-tension power lines or your TV set) are produced, and 
the material I've seen generally does not provide safety features in the 
design or safety precautions in the operating instructions. Assertions can 
be seen stating that "low currents" are produced, but I've not seen 
quantification or any other assurance that these currents are limited to 
harmless levels. One plan even prescribes powering these devices directly 
off ordinary household 120 volt AC power (that alone is a very dangerous 
and foolish recommendation). You can be killed, whether these devices are 
AC powered or not.  The electrons that zap you won't care that you were 
innocently following the instructions on somebody's Web page.  

Seriously -- DON'T build or experiment with Tesla's inventions (even 
if you buy a kit or finished, working product) without getting guidance 
from a qualified electrical engineer or physicist who understands how these 
devices work and who can ensure appropriate safety measures are taken in 
their construction and operation. I wouldn't attempt this myself without 
that kind of guidance from a knewledgeable source, and I'm a practicing 
electrical engineer (who hopes to become an *old* engineer :-)

Regards,

Steve Czarnecki

"There are old pilots and bold pilots, but no old, bold pilots."
    -- aviation adage, source unknown