Relation between renewable_capacity_factor and capacity_factor for wind_ppl

[SongminYu]

Hi, I am trying to develop the power system part in a MESSAGE model following this tutorial. When adding the wind_ppl, I noticed that there are two "capacity factor" parameters: renewable_capacity_factor and capacity_factor. I am a bit confused about their relationship, and how they correspond to the "capacity_factor" in other power system models, i.e., annual full-capacity generation hours divided by 8760.

In the tutorial, I extracted the values of the two parameters as follows:

(1) renewable_capacity_factor

(2) capacity_factor

Here are my questions:

First, what is the relationship between the two parameters?

Second, I want to know if I understand right: the multiplication of the two "capacity_factor" is comparable with the "capacity_factor" in other power system models, i.e., annual full-capacity generation hours divided by 8760?

Thank you!

[SongminYu]

I found some explanation on this page regarding renewable_capacity_factor:

Equation RENEWABLES_CAPACITY_REQUIREMENT

This constraint connects the capacity factor of a renewable grade to the installed capacity of a technology. It sets the lower limit for the capacity of a renewable technology to the summed activity over all grades (REN) devided by the capactiy factor of this grade. It represents the fact that different renewable grades require different installed capacities to provide their full potential.

So, renewable_capacity_factor is a factor on the renewable_potential, not related to the operational aspect? This sentence is still not clear to me...

Besides, next to the capacity_factor of technologies, another parameter called operation_factor is also mentioned in this page. But it is not mentioned in the tutorials. A brief explanation of

• operation_factor of technologies
• capacity_factor of technologies
• renewable_capacity_factor of renewable resources

would be much appreciated!

Thanks!

[glatterf42]

Hi @SongminYu and sorry for the late reply!
In general, I think your understanding is correct, but let me try to add a little more context here. Maybe @SiddharthJoshi-Git can jump in and correct me if I'm wrong 🙏

So when you define renewable energy technologies, they have the usual capacity_factor that all technologies have. In contrast with e.g. coal power plants, they do not have a limited supply of resources, though. However, they are also limited by other factors: for wind, there are winds of different velocity, which generate different amounts of energy (I imagine). For the sun, the angle at which the light rays reach us influences how much energy can be captured, among other things. So when dealing with renewable energy technologies, we have to capture this inefficiency with another factor: renewable_capacity_factor.
So assume you have a renewable technology with only one grade, then the model will use the renewable technologies only to the limit that ACT/CAP needs to be smaller or equal to the product of capacity_factor, renewable_capacity_factor, and operation_factor. In practice, the operation_factor is often set to 1, and people call the product of capacity_factor and renewable_capacity_factor the true_capacity_factor.
The operation_factor is defined as the ratio of the number of hours the technology was on-line (i.e. active) to the total number of hours in the reference period. So this allows you to define that a technology needs to be inactive every so-and-so hours for e.g. maintenance.
Of course, when you begin to introduce multiple grades of a renewable technology, the calculation is not as straightforward to arrive at something like a true_capacity_factor, but the general idea remains the same: capacity_factor describes the fraction of installed capacity that can be active during any one period, while renewable_capacity_factor describes the fraction of this renewable energy grade's potential that can be used.

Please let me know if this answers your question :)

[SongminYu]

Hi @glatterf42, thanks for your explanation! It is clear to me now.