NERC Disturbance Control Standard specifies that regulating and supplemental reserves must be able to reach their full capacity within 10 minutes, but since capacities may differ dramatically, this definition will not describe the feasible MW increase within a minute. For instance, a 50 MW unit that meets the aforementioned standard will have a ramp rate of at least 50/10 = 5 MW/min, but a 500 MW will have a ramp rate of at least 50 MW/min. We cannot consider 5 MW/min to be as good as 50 MW/min!
In Australia, our market operator makes the following assumptions for new generation capacity:
| Technology | Fuel | MW/hr | MW/Min |
|----------------- |--------------------|-----------|-------------|
| CCGT | Natural Gas | 600 | 10 |
| OCGT | Natural Gas | 1200 | 20 |
| Supercritical | Black Coal | 900 | 15 |
| Supercritical | Brown Coal | 900 | 15 |
See the fuel and technology data (and documentation) on this page: http://www.aemo.com.au/Electricity/Planning/Related-Information/Planning-Assumptions
Existing plants (in Australia) achieve rates much higher than this in practice.
As a note, and relevant to your question, the rates in MW/min are important (not rates relative to full installed capacity).
As far as I know, that capacity is what the reserve provider has committed to dispatch within 10 minutes. Hence, each provider should consider their ability of ramp up (generator) and ramp down (demand/loads) when bidding in the reserve market. For the generators, there is the ramp up limit. However for the loads, they can simply turn off their loads by switching breakers - where there's no ramp limit.
In particular, an aluminum smelter plant is able to switch off their pot-lines (each pot-line is around ~100 MW loading level) within seconds. Detailed data can be found here:
https://www.researchgate.net/publication/282743180_Bidding_strategy_in_energy_and_spinning_reserve_markets_for_aluminum_smelters%27_demand_response
Article Bidding strategy in energy and spinning reserve markets for ...
So far I could find from several (and quite different quality!) sources, we have that:
Ramp Rate Down Time Up Time
[MW/min] [min or Hr] [min or Hr]
Solar 200 0,5 [min] 0,5 [min]
Pump Hydro 200 0,5 - 1 [min] 0,5 - 1 [min]
Hydro Reservoir 150 1 - 5 [min] 1 - 5 [min]
Wind 30 - 60 1 - 2 [min] 1 - 2 [min]
Gas Turbine 20 - 50 2 - 20 [min] 2 - 20 [min]
Nuclear 20 1 [hr] 1 [hr]
Ngas / Steam 10 - 20 1 [hr] 1 [hr]
Oil / Steam 1 - 7 2 - 10 [hr] 4 - 12 [hr]
Coal / Steam 2 - 4 4 - 48 [hr] 8 - 24 [hr]
Hope it helps!
This company from Finland claims to have achieved 120% per second ramp rate with their gas turbine.
http://www.wartsila.com/energy/learning-center/technical-Add your answercomparisons/combustion-engine-vs-gas-turbine-ramp-rate
https://posoco.in/download/analysis-of-ramping-capability-of-coal-fired-generation-in-india/?wpdmdl=23042
Wartsila touts combustion engines as starting in 2 minutes - 50%/min.
"Wärtsilä 34SG combustion engines have true quick start capability – an effective ramp rate of 50% per minute, reaching full load within 2 minutes." https://www.wartsila.com/energy/learn-more/technical-comparisons/combustion-engine-vs-gas-turbine-ramp-rate
Literature Review Concerning the Cycling Cost in a Power System with Renewable Power Sources Wu 2018
https://pdf.sciencedirectassets.com/277910/1-s2.0-S1876610219X00028/1-s2.0-S1876610218310348/main.pdf?
My suggestion is to compute the real available ramp rate from first principle. That is from name plate inertia, probable operating points and operating modes of each generators. That would be more accurate bearing in mind you are not dealing with non linear stuffs.
Hi Alejandro Hoese ,
Are these Down Time and Up Time are starting and Shutdown time or they are the minimum up and down time?
Do you know whether there exists any database that contains the startup and no load cost for different types of generators?
Regards,
Hi everyone, any idea on the rate of change of a unit for a delivery time of 10 seconds? basically the primary frequency governor response. Sat hydro, thermal, coal, etc
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