I'm trying to understand the properties that control power plant aging. The minimum age of an unmodified coal plant is supposed to be 38 years (I think this comes from the official guide). But looking at the properties in the SC4tool building reference what I see is a bunch of numbers (16 of them) for "age to maintenance cost multiplier response curve", another similar bunch for "age to output level response curve", a single age degradation rate number (0.001111) and a soft failure threshold (0.898).
Can anyone explain how to interpret these numbers?
Let's take the values for the coal plant as an example:
The
Age degradation rate is 0.001111
This tells you the degradation per month. This number is added every month to the accumulated degradation.
Once the degradation reaches the value given in Soft Failure Threshold (=0.9), the plant will show visual distress and have frequent outages.
Once the degradation reaches the value given in Hard Failure Threshold (=1.0), the plant stops working or blows up (as given in the property Hard Failure Type).
In other words, after 1/0.001111 months = 900 months = 75 years you won't get any power at all from a coal plant.
The
Age to output level response curve consists of 8 paired values, relative age and relative output level:
| Relative Age 0.0 | Real Age | 0.0 years | Output level | 100% |
| Relative Age 0.4 | Real Age | 30.0 years | Output level | 95% |
| Relative Age 0.5 | Real Age | 37.5 years | Output level | 92% |
| Relative Age 0.6 | Real Age | 45.0 years | Output level | 86% |
| Relative Age 0.7 | Real Age | 52.5 years | Output level | 77% |
| Relative Age 0.8 | Real Age | 60.0 years | Output level | 60% |
| Relative Age 0.9 | Real Age | 67.5 years | Output level | 35% |
| Relative Age 1.0 | Real Age | 75.0 years | Output level | 0% |
The
Age to maintenance cost multiplier response curve consists of similarly 8 paired values, relative age and relative cost:
| Relative Age 0.0 | Real Age | 0.0 years | Monthly Cost | 100% |
| Relative Age 0.4 | Real Age | 30.0 years | Monthly Cost | 103% |
| Relative Age 0.5 | Real Age | 37.5 years | Monthly Cost | 105% |
| Relative Age 0.6 | Real Age | 45.0 years | Monthly Cost | 115% |
| Relative Age 0.7 | Real Age | 52.5 years | Monthly Cost | 130% |
| Relative Age 0.8 | Real Age | 60.0 years | Monthly Cost | 155% |
| Relative Age 0.9 | Real Age | 67.5 years | Monthly Cost | 185% |
| Relative Age 1.0 | Real Age | 75.0 years | Monthly Cost | 300% |
Between the given threshold values, the output level and cost multiplier are linearly interpolated.
Thanks, that's clear (at least to me)! :thumbsup:
I guess usage level during the month must modify the age degradation before it's added to the accumulated degradation -- or else the stuff about power plants aging faster if they're run harder is wrong? To get the 38 year minimum lifespan for a coal plant would require doubling the degradation. I don't know where I got this 38 number from, its in a spreadsheet I have from when I played the game a couple years ago that tries to calculate the lifetime average cost per MWh taking all costs into account. But my spreadsheet is clearly too simplistic.
There are two properties in the
Utilities Simulator exemplar that set these:
The
Funding percentage to decay rate multiplier response curve gives a slight variation on the rate of degradation:
| Funding Level | 0 % | Degradation Rate | 110 % |
| Funding Level | 100 % | Degradation Rate | 100 % |
| Funding Level | 120 % | Degradation Rate | 90 % |
The
Usage percentage to decay rate multiplier response curve gives a larger variation on the rate of degradation:
| Capacity Used | 0 % | Degradation Rate | 10 % |
| Capacity Used | 25 % | Degradation Rate | 20 % |
| Capacity Used | 50 % | Degradation Rate | 45 % |
| Capacity Used | 75 % | Degradation Rate | 85 % |
| Capacity Used | 90 % | Degradation Rate | 125 % |
| Capacity Used | 100 % | Degradation Rate | 155 % |
| Capacity Used | 110 % | Degradation Rate | 200 % |
A lifespan of 38 years would be a result of using the plant at 110% capacity.