Construction time in the MESSAGE model

[Alaa-Eltablawy]

Hello,

How does the construction time impact the activity of technologies?
I've noticed that when I set a specific construction time for a technology, it actually won't impact when this technology will be deployed.
For example: for technology X the construction time is 5 years, so I'm expecting that at least for the first 5 years of this plan there will be no activity for technology X, but what I've observed is that the output could show activity for technology X in the first 5 years.

[glatterf42]

Hi @Alaa-Eltablawy, thanks for your question :)
Searching our docs for "construction time", you will find this explanation: In the current formulation, construction_time is only taken into account when determining investment costs, but newly-built capacity is available for the model immediately.
The investment costs need to be adapted because if you construct a technology over e.g. five years, your investment costs will be split over five years, too. However, money is losing value according to the interestrate, so you will need to invest more in later years.
Aside from this cost adaptation, which should take place before the technology becomes active, there's no effect of the construction_time. Please also see this equation as to how the construction_time_factor enters the wider calculations.