Fixing initial periods using FIXBOH

[NeilGrant]

Hi there,
I am wondering if anyone could enlighten me on how the FIXBOH option in VEDA works? I am currently creating mitigation scenarios, where I fix action up to 2020 based on a reference scenario which captures only current climate and energy policies.

When I look at the results in VEDA_BE however, the results in 2020 for the mitigation run are very slightly different to the results for the Reference Scenario - so they haven't been entirely fixed - for example emissions or system costs show slight deviations between the scenarios.

I am:
- Running with price-elastic demand, and using this same Reference Scenario to generate the base prices - could this be responsible for the (small) deviation? Is it recommended to do this differently (i.e. use different scenarios for fixing initial periods and generating base prices)?
- I am also sometimes evolving technology costs between the scenarios (e.g. solar costs in 2020 may differ between the scenarios). I can see that this could be the problem.

When using FIXBOH, does the model simply overwrite initial periods with data from the Reference Scenario .gdx? If so, I am confused as to where the difference arises. 

If anyone could enlighten me further, that would be very appreciated.

Cheers,
Neil

[AKanudia]

You seem to know how it works in VEDA. Your question is about how it works in TIMES. My understanding is that values of some key variables are fixed to the selected scenario. Antti will be able to give more precise details.

[Antti-L]

The fixing means that (nearly) all the variables of the model are fixed to the levels in the previous solution. However, all the reporting parameters are re-calculated also for the fixed periods, using the parameters of the current run, but the variables which have been fixed will of course have their fixed values while calculating the result parameters.

Therefore, if you change costs, emission factors, or other parameters, such changes will of course be reflected in the reporting parameters. Please do not change any parameters for the fixed periods if you want to keep the results for those periods unchanged.

[NeilGrant]

Dear Antti and Amit,
That's very helpful - thanks for clarifying that with me!

All the best,
Neil