http://www.eurotrib.com/comments/2008/2/22/132124/905/36

In the case of Texas, it seems at first blush it actually works pretty poorly. Somewhat flat, at least from the meteorology point of view, hence a very large weather pattern, the same pretty much everywhere. Plus an adverse correlation between seasonal and intra-day wind frequencies and consumption (lower winds overall in summer and lower winds in the evening at peak load).

It can make sense overall but it really requires tight coordination between the different sources.

And pumped storage, sure - it helps any type of generation - but where?

Anyone dabbling in electricity needs to remember that "acceptable" for grid availability means 99.99%, less than an hour of load-shedding a year. The fact that the grid itself is falling apart in the US by lack of maintenance and investment doesn't help. But even with lowered US expectations, any solution that reaches only 96% or even 99% has a problem. 99% means nearly 4 days without juice a year. That's 3rd world.

The "high fuel consumption" is all relative - it's high per kWh produced, but no so much in overall terms, so it's an acceptable trade off.

How much? I don't have hard numbers so I'd like you to come up with them as this is a wind problem :)

But my limited knowledge of rotary and thermal machines tells me at least 20% from rated power consumption to maintain pressure, minimal flow and, most important, temperature. Maintaining a stable temperature is absolutely essential. Otherwise you break things like exchangers or turbine blades on fast ramp-up. Maintaining a stable temperature profile is also vital in the flue system for pollution control or you start spewing NOx and, if there any halogen in the fuel, dioxins.

~~~~

Your link is too long to do it justice and properly eviscerate it.

It's BS. The guy is simply projecting his British incompetence on the French system.

He's flat out wrong about nuclear "inflexibility". Wrong as in "just plain wrong". EdF performs load following with its nuclear power plants and even shuts down some of them over weekends to kick them back online in the wee hours of Monday mornings. That's why the capacity factor of French nukes is pretty low - 75% vs. 90 to 95% in the US - but their availability is much higher - 85% to 95%.

He's also completely off-base on EJP. It's about grid reliability and the fact that EdF - by virtue of being a well-run monopoly with high technical know-how - has been in a position to do load management way, way before it was cool.

EdF is simply taking advantage that for many industrial clients, even the level of reliability offered by EdF is not enough. So those clients MUST have a backup no matter what. When an industrial oven looses juice, you don't lose just the melt and a day of production. You loose the oven. The clean up is done with circular saws, jack-hammers and cutting torches and the oven has to be rebuilt pretty much from scratch. For things liek aluminum refining, a lose of power for more than a few hours is simply catastrophic. The entire plant is lost. So EdF is giving those clients with backup that deal so it can shed load very quickly if something goes wrong. And some other customers with high electricity bills make the math and jump on board. The result is a very stable grid.

When I was in Paris, nearly two year, I've had all in all 0 blackouts. Zero. I was in the 15ème. I know that there are more problems in some of the inner arrondissements because of the age of the local distribution equipments and the difficulty to maintain and replace them (very cramped sheds, low accessibility, street work is a nightmare, etc.). But EdF reliability for consumers is pretty amazing.

In comparison, since I've been back in the US in the tender care of PG&E - not even two years - I can count at least 6 times without juice at home or at the office. Actually I even had to buy a special alarm clock with an integrated battery backup, one that rings the alarm even without grid juice, not just to keep the hour. And thanks God, there are showers at the office.

And the rant about overnight water heaters. Please...

At this level, I'm not sure if it's Anglo disease or Mad Cow disease.

Not under normal conditions for a CC plant. Either you kill the plant and you pay the bill later in maintenance or you spew pollution in huge amounts by using abnormal mix or PC to speed up the approach to temperature.

And there's no time scale on Siemens pretty chart...

The best GE can do with a CC plant is a ramp-up to 100% in 90 minutes on a hot start after 8 hours shutdown.

Siemens must be endowed with some unknown form of genius. What they propose is really outside of the norm and they state a 20 years expected life time on their systems. I'm curious to see in what shape their Benson boiler will be after 7,000 fast ramps.

I'll believe Siemens in four or five years when there is a little bit of experience on those types of procedures.

Those babies run at 250 bars and 600°C. They were all the rage in the late 50s, early 60s when they were first introduced and then they started to spring cracks everywhere due to static stress and temperature cycling and a lot of plants switched back to subcritical boilers with the traditional drum and superheater. The technology has clawed its way back and is now the norm in new coal and CC plants and is really efficient. But the industry has learned to be very gentle with supercritical boilers. Not your average cooking pot.