Subject: Priorities Posted: 9/22/2016 Viewed: 4968 times
Hello, could someone please explain me how priorities work? I know they follow a logical statement - if I set priority (1) for a demand site, it will be attended first, and then WEAP will attend whatever has the second priority on the list. However, I did a simple exercise in my simulation, where I change priorities of flow requirement, top of buffer, reservoir filling and hydropower generation. Say I've already defined the first three priorities to be attended, if I set hydropower generation to 4, it should be the last. However, the results were different when setting hydropower priority to (4) or to (99). Why it is so?
Is there a difference in setting priorities in the order: (1), (2), (3) compared to (1), (50), (99) ?
Does the priorities account for units? If I set priority (1) for demand, is it different from setting priority (1) for hydropower generation?
Subject: Re: Priorities Posted: 9/27/2016 Viewed: 4902 times
The demand priorities are all about telling WEAP which demand sites to prioritize in the event of water shortage.
For your example, if you have only 3 demands in the system, then setting them as (1), (2), and (3) will not be any different from (1), (50) and (99). It's all about the order. WEAP starts with the highest priority and then looks for the next one down.
Priority does account for units - in that WEAP is trying to supply as much volume (often measured in cubic meters) as is demanded/available by supply. However, when there is a deficit and WEAP has two demand sites with the same priority, it will split the deficit between them by percentage - for example, they would both receive 85% of their demand for that time step.
In terms of the question of hydropower priority - is your system generating hydopower? Also, there should be no difference between setting the hydropower priority for 4 or 99, provided that there are no other interim priorities listed in your system. Do you know if there are?
Subject: Re: Priorities Posted: 9/27/2016 Viewed: 4898 times
Thank you for your reply. I forgot that I had changed a hydropower priority of one reservoir and not for the others, so that when I changed it to 99 instead of 4, it was actually less important in the priority list. Yes, my system is generating hydropower.
Subject: Re: Priorities Posted: 3/15/2017 Viewed: 3996 times
What happen when demand priorities at upstream to 2 and demand priorities at downstream to 1?