EQ_Peak interpretation

[krakowski]

Hello,

I was wondering how exactly I had to interpret the value of EQ_Peak in VEDA_BE?

I believed that EQ_Peak imposed an installed capacity larger than the peak demand, so one could expect that this constraint is always saturated (i.e. there is no reason that the model install more capacities than the one required by the peaking equation). But with different scenarios and even different models, I often observe non-zero value for EQ_Peak which means that the constraint is not saturated. How should I interpret non-zero values of EQ_Peak?

Moreover, EQ_Peak and EQ_PeakM have often a non-zero value at the same time, how is it possible?

Thankyou in advance for your answer.

Vincent

[Antti-L]

From the GAMS User Guide:

Equation level .l   – Optimal level for the equation which is equal to the level of all terms involving variables

Consequently, the level of EQ_PEAK can be non-zero even when the constraint is active (i.e. when the constraint is satisfied as an equality) because the constraint usually involves also a constant term (due to existing capacity stock).

But you are right: Usually there is no reason that the model should install more capacities than what is required by the peaking equation.  However, if you define only a small peak reserve requirement, while the availability factors of the producing technologies may already be imposing some reserve capacity, you could of course end up having more capacity than required by the peak equation.

(Note that NCAP_PKCNT is by default 1, which means that the full capacity is assumed to contribute to the peak.)

[krakowski]

Thank you very much for your enlighting answer.