I claimed recently that fossile fuel electric power plants convert about 33%
of the chemical energy in its fuel into electrical energy, to which
M R replied:

> Is this really true, then why do the automobiles run
> at 35 - 40 % efficiency. After all they convert heat
> energy directly into mechanical energy.

Since I have retired and moved away from my former college environment, I no
longer have the easy access to information sources that I once had. (There
are a few books of my own that I got rid of and now regret.) But I believe
quite definitely that the 33% I quoted for the efficiency of fossile fuel
powered electric generating plant is an accurate approximation. But I cannot
be positive and I cannot check my sources.

I have no convenient way of checking to see if MR's figures for automobile
efficiency are accurate either, but it would not surprise me to see that
auto engine efficiency values are in the same general range as electric
power plant efficiency. Why not?

Regards, Bill Hooper
physics professor (retired), Florida, USA

P.S.

M R went on to state:
> ethanol from genetically modified Corn will give
> more net energy.  The plants get lot of energy from
> Sun (through photosynthesis).
Surely that should read "The plants get ALL their energy from the Sun
through photosynthesis."
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