Topic: Optimization overdependent on only 1 source. How to diversify?Subscribe | Previous | Next
Mohd Hafdzuan Adzmi 8/3/2015
979 Views hi all,
I was just wondering if anyone can shed some light on endogenous capacity addition using the optimization feature.
Based on my model i observed that somehow optimization does not take into account how long a plant can be built. It kept adding coal every year until the end of simulation year which i assume is the least cost option.
And there seems to be less diversification even when i restrict the maximum capacity addition (e.g. 1000 MW for for coal). And the result seems overdependent on coal unless i specify externalize cost. But this will lead to the model being overdependent on nuclear. Wondering if its the model or my input parameter for renewable is not correct or cheap enough. I think reneables is a cheap option considering the aggressive cost reduction and also externalize cost applied.
I restricted maximum capacity addition for renewables to 30MW to ensure for more realistic (less Renewable) reflection of the real world ..
help ..
cheers
mohd adzmi
Taylor Binnington 8/4/2015
978 Views Hi Mohd,
I'm not sure what you mean by "optimization does not take into account how long a plant can be built", but I think I can help answer the rest of your question.
As with all optimized solutions, the optimal solution determined within LEAP will return the least-cost (lowest net present value) construction and dispatch of power plants, subject to any constraints you specify. If you do not specify constraints, then LEAP will simply build and dispatch the single lowest cost technology.
If you want to restrict the total installed capacity of each type, I would suggest you look at the Maximum Capacity variable:
http://www.energycommunity.org/WebHelpPro/Transformation/Maximum_Capacity.htm
The Maximum Capacity *Addition* variable controls only how much capacity can be added in a single year.
Hope this helps,
Taylor
Mohd Hafdzuan Adzmi 8/4/2015
977 Views Hi taylor,
What i meant by built time is that, if optimization endogenously add a 1000 MW nuclear plant, wouldn't it take some time before it can be fully operational? So nuclear generation should not appear after only the plant is commissioned? It seems like a plant is added (built) and dispatched in the same year.
In terms of restricting the capacity is my understanding below correct.
To limit nuclear power plant installed capacity in a particular year use - maximum capacity variable:
input: 1000 MW (1 plant = 1000MW)
To limit nuclear power plant overall capacity in a particular year use - maximum capacity addition variable:
input: 5000 MW (which imply 5 nuclear plants)
I was doing it the other way around.
thanks for your help
Mohd Adzmi
Taylor Binnington 8/4/2015
976 Views Hi Mohd,
Capital costs for power plants in LEAP are assumed to represent the cost of overnight construction - therefore the year in which the plant is built is the year in which is becomes operational.
Your understanding of Maximum Capacity and Maximum Capacity Addition is not quite correct. Maximum Capacity Addition limits the amount of capacity which can be constructed in any one year:
http://www.energycommunity.org/WebHelpPro/Transformation/Maximum_Capacity_Addition.htm
Total allowable capacity is regulated by the Maximum Capacity variable.
Best,
Taylor
Mohd Hafdzuan Adzmi 8/4/2015
975 Views Hi taylor,
This had helped a lot. however, upon your suggestion i tried to limit the capacity and LEAP could not optimize (error). Something about could not find a solution. Then the screen highlighted the expression in the system energy load shape tab in red.
I hope you can help me to fix this. Optimization can only work when i set unlimited for all processes in the maximum capacity variable which doesn't seem to be the most realistic way to optimize and feels like i'm forcing the result.
Thanks.
Mohd Adzmi
Taylor Binnington 8/4/2015
974 Views Hi Mohd,
Be sure that you are not specifying optimization constraints which conflict with one another. In this event, you will be given an error message "No primal feasible solution found", indicating that no solution exists for the problem.
I would recommend that you carefully review your inputs for this problem. If you're modifying the Maximum/Minimum Capacity variables, be sure that they do not conflict with your Maximum/Minimum Capacity Addition variables. This is easy to do accidentally - for example, specifying a Minimum Capacity Addition which will eventually cause the installed capacity to exceed the Maximum Capacity variable will generate such an error.
Hope this helps,
Taylor
Fran Lallana 8/5/2015
968 Views Hi Mohd,
I'd recommend you to use the varialbe "Minimum addition size", in which you can specify the smallest module size you would add if this plant type is selected to be constructed. If not, the optimization decides the exact power required even if not a commercial nor technical size over a "continuum".
Additionally you could specify some period of time where it would be impossible to add some specific type of capacity due to construction limitations, with a TimeSeries expression in the variable "Maximum capacity addition", like Interp(Baseyearvalue, 0, Baseyearvalue+10, 1000000).
To enable the variable "Minimum addition size" go to Basic Parameters: Optimization: Enable Addition Size.
Hope it helps,
Regards,
Fran.
Mohd Hafdzuan Adzmi 8/6/2015
964 Views hi Fran,
Thank you for the suggestion. i realized that i also need to enable the mixed integer linear programming in the basic parameter for that function to show up on the variable tabs. I'll try both method since it does take sometime for LEAP to optimize.
Cheers,
Mohd Adzmi