[SGVLUG] Off-topic - US govt energy site - interesting statistics

[David Lawyer]

On Mon, Dec 31, 2007 at 12:57:27PM -0800, Stan Schwarz wrote:
> > While the EIA has some significant data, I can't seem to find some of
> > the most important data using this "homepage" url.  One important item
> > is the thermal efficiency of generation electricity from fuel,
> > expressed as an inverse of efficiency in BTU/kwh and known at the
> > "heat rate".  In 1960 it was about 10,760 BTU/kwh and today it's not
> > much better (10,400 +- BTU/kwh).  That's 45 years of stagnation in
> > improving energy efficiency.  One reason: save $ on capital
> > investment.
> 
> It's my understanding from the energy lecture series here at
> Caltech that the efficiency of converting heat to electricity
> is about as efficient as it's ever going to get. There are
> some fundamental thermodynamic limits on it. Steam turbine
> technology is pretty mature, so it's about as close to the
> theoretical limit as is possible.

Yes but we are way below that limit because power plants have often
chosen to save $ and buy less efficient plants.  The most efficient
plant might use GE's turbines (H system):
http://www.ge-energy.com/prod_serv/products/gas_turbines_cc/en/h_system/index.htm
It claims that the turbine is 60% efficient which sounds too good to be
true.  Well, elsewhere it claim that the one plant in actual
operation is almost at 60%.  I'm wondering if this includes auxiliary
power needed for feed-water pumps, etc.  And auxiliary power might be
say 5% of generated power.  At any rate power plants are available at
net efficiencies of well over the existing 33% average.

Who is buying this GE turbine?  Nobody in the US.  Except GE is now
installing one nearby S. of Riverside, which will be owned by GE.  If
you can't sell them, use them yourself.  One reason for no sales is
that this uses a combined cycle using natural gas, and natural gas
prices have risen.

The fact that power plants reject more costly but more efficient
hardware may (or may not) result in energy savings, since a more
costly system requires more energy to design and manufacture it.

			David Lawyer