Modelling a Pondage based Run of River plant

[vsaini]

Dear Members,

Greetings of the day.

I would like to know your thought on modelling a Pondage based Run of River plant that has the following characteristics:

The plant capacity is 100 MW and its having pondage of 6 hours every day i.e. the plant can run at full capacity for 6 hours every day (these types of plant are preferably designed for meeting the peak). Now if the plant load factor for the month of April is 40% (as per available data) then its monthly generation will be 28800 MWh (as only monthly data is available with me). This highlights that although the plant had 6 hour pondage but its generation is more than 6 hours every day.

 

Now to model this kind of plant I am sharing with you my modelling approach (please find below), but I would like to know your views and suggestion on the same. You may suggest some other alternatives and it will be really great as I have to model around 10 PROR plants.  

 

Approach: I have used the following parameters for the modelling of PROR plant:

My model is an hourly model that’s solves demand and supply for each hours. For each year, I have 12 months and 288 time slices. Each time slice representing one hour of a day for each month i.e. April 01Hr time-slice represents first hour (12 a.m. to 1 a.m.) of each day in April and thus every month will have 24 time-periods. 

 

Process Name: PROR-HYDRO

NCAP_AF – Upper bound for all the hours of the month as 100% i.e. H01 to H 24 all values as 1

NCAP_COST-  1583 Million USD per GW

NCAP_FOM- 25 Million USD per GW

NCAP_TLIFE- 50 Years

NCAP_PASTI- 0.100 GW

Process Filter: HYDRO (selects the 100 MW PROR –HYDRO process)

Now to restrict the generation in April Month from 100 MW PROR plant to 28800 MWh (equivalent to PLF of 40%), I will use a user constraint modelled as mentioned below:

User Constraint: Month April-PROR

Total Gen April (Process: PROR-HYDRO) - PLF* Total Cap(Process: PROR-HYDRO) * Hours April Month*Conversion Factor (GWH into PJ) <= 0

For April Month the Equation will be:

Total Gen April (PROR-HYDRO) – 40%* 0.100 GW* 730* 0.0036 <= 0

Looking forward for your response.

 

Warm Regards,

Vinay Saini

[Antti-L]

I am not sure I understand the modelling issue, but concerning the User Constraint:

   Total Gen April (PROR-HYDRO) – 40%* 0.100 GW* 730* 0.0036 <= 0

Isn't this equivalent to defining NCAP_AFS(PROR-HYDRO,April,UP) = 0.4 (utilization factor in April is at most 40%)?

However, I can see that one might also want to model the storage size and inflow distribution as well, such that the power output would be limited by both. In the latest version (v3.9.5, to be released in the next days) that can be accomplished by defining the process as a timeslice storage, and by using NCAP_AFC/NCAP_AFCS for defining the availabilities for both the input flow (i.e. the inflow distribution) and the output flow (output availability/utilization factor), and for the activity (storage pondage capacity). If you want pursue that approach, I can provide more details.

[vsaini]

Dear Dr. Antti,

Thank you for the reply
Yes you are right about using NCAP_AFS as it solves the same purpose and somehow using this completely skipped from my mind [ I guess due to work pressure ]. In my previous model I used NCAP_AFS only for defining hydro plants.

Regarding NCAP_AFC/NCAP_AFCS, I would like to know more in details.

Warm Regards
Vinay Saini

[Antti-L]

Ok, here are some additional details:

If we assume that the inflow is evenly distributed over the daily hours, we can immediately calculate the pondage storage capacity from the constraints that 1) the plant can run at full capacity for at most 6 consecutive hours every day, and 2) the daily load factor is at most 40%. The storage size can be then calculated as 6/24–0.4*6/24 = 0.15 of the nominal daily maximum production (2400 MWh), i.e. 0.15*2400 = 360 MWh. The figure below illustrates an example production pattern fitting the two constraints:


As you can see, the maximum number of consecutive full load hours is 6, and the daily load factor is 40%, just as required.
The three horizontal lines shown in this figure represent the operational constraints: The topmost line is the storage capacity (=3.6), the blue line is the plant output capacity (=1), and the lowest line is the assumed even inflow distribution (=0.4).

With TIMES v3.9.5, these three constraints can be modelled by specifying the following parameters:

PARAMETER NCAP_AFC /
CH.0.PROR-1.ACT.DAYNITE -1
CH.2010.PROR-1.RORIN.DAYNITE 0.4
CH.2010.PROR-1.ELECTRICITY.DAYNITE 1
/;

PARAMETER NCAP_AF /
CH.2010.PROR-1.ANNUAL.UP 0.15
/;

Here, PROR-1 is name of the process, and RORIN is the input flow (inflow). The process is a DAYNITE level timeslice storage process, with input RORIN, output ELECTRICITY, and PG=ELECTRICITY.

[vsaini]

Dear Dr. Antti,

My heartfelt thanks for your efforts and constant support

Thank you for the detail answer. will read it thoroughly and model it in my model.

Warm Regards
Vinay Saini

[Ansh_02]

Greetings Dr. Antti,

I was trying to model storage plants in ANSWER TIMES and in this post you replied on 14-06-2016, 06:22 PM, I couldn't understand the parameters that you have explained. It would be great if you give a detailed explanation of the parameters that is used in that post.

[Antti-L]

PARAMETER NCAP_AFC /
CH.0.PROR-1.ACT.DAYNITE -1
CH.2010.PROR-1.RORIN.DAYNITE 0.4
CH.2010.PROR-1.ELECTRICITY.DAYNITE 1
/;

The first NCAP_AFC entry is just a flag for triggering independent NCAP_AFC equations.  
Normally, NCAP_AFC equations are defined for the whole PG group, and in that case the normal EQ_CAPACT equations are not generated at all. But in this case it is more convenient to keep the EQ_CAPACT equations for defining the availability factor for the storage capacity.  Therefore, the flag  CH.0.PROR-1.ACT.DAYNITE -1.

The second NCAP_AFC entry defines the maximum DAYNITE input availability factor: The input flow is assumed evenly distributed, at the level of 40% of the turbine capacity. So, the value is 0.4. You could also define timeslice-specific values for it.  

The third NCAP_AFC entry defines the maximum DAYNITE output availability factor, which is assumed 100% of the capacity. Thus the value is 1.

PARAMETER NCAP_AF /
CH.2010.PROR-1.ANNUAL.UP 0.15
/;

Finally this NCAP_AF parameter defines the pond storage availability factor.  As mentioned, the size is 0.15 of the nominal daily maximum production, and thus the value is 0.15.