In article ,
Neon John wrote:

Even Roland's appreciation of the "big picture" is incorrect. Modern
supercritcal fossil plants achieve overall efficiencies in the 50% range.
Even the good old nuke are in the high 30s. The Sequoyah Nuclear Plant where
I worked for about 10 years recently replaced the steam generators. The
improved design plus some plant upgrades pushed the efficiency to 38% and a
fraction, something that spawned a small staff party. Oh, and BTW, Roland,
the waste heat goes up the cooling tower stacks and not into the lake, at
least not to any significant extent. Much to the chagrin of local fishermen
who discovered that the warm water (pre-cooling towers) spawned great fish
growth and fishing conditions.
John De Armond

Depending on *how* it's measured, efficiency can be higher. Back in '70,
I worked as a co-op at the Eddystone plant (Philly area), then arguably
the most efficient plant in the world -- only the USSR supposedly had a
better one. Steam started at 4,999.5 psi according the gauge, ended in
partial vacuum. They burned (actually closer to exploded) 1-200 tons of
coal an hour and we STILL needed heaters in the "basement" labs in the
winter. [yes, we had walls ;-)] They only used the gas turbines (jet
engines) in the yard when absolutely necessary, because their efficiency
was so low.

By each measure, efficiency was pretty high.

But are they making plants like that any more? When they built units 3 &
4, they went back to a "mere" 1-2000 psi. AFAIK, only one supercritical
production nuke was built: Peachbottom.

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/