Re: Brown Out Blair Out Cameron Out
Our hydro is "STOR" (surge) demand - the typical example is a cup of tea in commercial breaks.
The "interruptible" contracts you're thinking of are probably the frequency response loads which can shut down instantly for up to 20 minutes (freezers and the like.) They exist to keep the Grid itself up and running while STOR starts up (75-360 seconds). They aren't there to get the peaking generators running.
CCGTs take a lot longer than you think to reach max. output - 40-50 minutes when 'hot', 75-110 minutes from 'warm' and 75 to 150 minutes from 'cold'*, although they can generate about 2/3 capacity within 30 minutes if you really go for it (treat them as a gas turbine). This is seriously fast for a fossil fuel system, the only faster ones are open cycle gas/petroleum turbine and conventional diesel generators which are used for UPS and grid STOR.**
The CCGTs are currently intended as "peaking" generators - peak demand is predictable so they are brought to temperature just in time to meet the peak demand at full efficiency.
You are right that at the moment we don't need to keep the gas running because wind and solar penetration is very low, and fully coverable by our existing STOR for long enough to get enough high-efficiency CCGTs going.
If current wind peneratration plans come to pass then frequency response plus STOR isn't going to be big enough for long enough to warm up CCGTs from cold.
So that leaves us building a lot more STOR diesels & turbojets and keeping more of the CCGTs warm and hot - both increase CO2 emissions.
Even now it is unclear whether we're actually reducing CO2 emissions when balancing the extra CO2 from the low-efficiency fossil-fuel STOR etc against the lower CO2 emissions of wind***.
Reading their recent publications it's clear that National Grid are shitting bricks. (Very diplomatically, but still...)
* Kehlhofer, R., et al., Combined-cycle gas & steam turbine power plants. 1999, Tulsa: PennWell Publishing Company.
** Boyce, M.P., Gas Turbine Engineering Handbook. 2006, Oxford: Elsevier.
*** Wind is not carbon neutral as it needs a lot of expensive maintenance, offshoire wind doubly so as it takes a lot of fuel oil to get out to the turbines.