LEAP

228 views | 4 messages Discussion: LEAP
Topic: Electricity generation does not meet expected behaviorSubscribe | Previous | Next

Antonio Chavez 11/27/2017

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Hello LEAP users,

We are trying to model the energy system of South Africa for a college project. We have input all the historical data and for year 2014 (base year) when we run the software, we obtain the right numbers and results on energy generation and energy demand.

An exhaustive research on the power plants of the country and generation capacity was done and input. Indigenous and exogenous capacities have been input and set to grow until 2030. Energy demand is set to grow along with GDP growth and population growth. Dispatch rule for the electricity generation is set as proportional to capacity.

We have two issues:

1. Energy generation suddenly drops in year 2015 and then it starts to grow. According to the input information, the normal expected behavior would be that the energy generation increases along with the demand. We do not know why this is happening.

2. Due to point 1 the model is not meeting the energy demand and it is importing energy. This is even stranger because we are setting Energy Imports to zero. We kindly ask for a clarification on why LEAP chooses to import in our simulation (despite setting import targets to zero) despite still having capacity for indigenous generation (tested with Full Capacity dispatch rule option).

Please find attached our LEAP model.

Thank you very much for the help you can provide us.

Best regards,

Antonio Chavez

Attachments:

groupsouthafrica_main-11-25.leap [10]

Taylor Binnington 12/12/2017

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Hi Antonio - good question. It's something that I occasionally see in LEAP models which takes some explaining.

Since your "First Simulation Year" is set to 2015, LEAP will begin dispatching processes in this year using your assigned ProportionalToCapacity dispatch rule, and your System Peak Load Shape. In years before this, it simply uses the assigned power generation for each process in the Historical Production variable (ignoring both the peak load shape and the dispatch rule).

If you had only a single time slice represented in your system load curve for the whole year (8760 hours), you would find an average power requirement that equates to the production of 28.653 thousand MW-years - this is your 2015 power requirement (look for this under Transformation: Requirements for the module). But you have many time slices in your load curve, and the shape is not flat, so there will necessarily be time slices during the year which have higher power requirements than other slices. Using your Exogenous Capacity and Maximum Availability variables, I calculate a total available capacity in 2015 of 43.2 MW, which is less than the power requirements for the highest three time slices (hours 0 - 3000 in your model). When LEAP performs its dispatch in these slices, it will not meet (and subsequently import) any remaining requirements beyond what your processes are capable of meeting.

Altogether this causes a discontinuity in power generation from 2014 - 2015, since in 2014 LEAP does not check the power requirements in each slice - it simply uses Historical Production for each process, regardless of whether there is sufficient capacity.

Hope this helps,

Taylor

Lijuan Zhao 7/17/2018

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Hi

I've been having the same problem recently. So I would like to ask have your question been solved and how.

Also, how to set time slice and percentage of system peak load.

Lastly，what is different between the Requirements and Outputs by Output Fuel in Resullts view.

Yours sincerely,

Zhao Lijuan

Emily Ghosh 8/1/2018

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Hi Zhao Lijuan,

Thanks for your questions. To answer your first question, here's how to set time slices and peak load shapes in LEAP:

Set up time slices through the setup screen accessed from the General:Time Slices menu. For more information, go to: http://www.energycommunity.org/WebHelpPro/Supporting_Screens/Time_Slices.htm
Create a load shape using load data through the Yearly Shape screen accessed from the General:Yearly Shapes menu. For more information, go to http://www.energycommunity.org/WebHelpPro/Supporting_Screens/Load_Shapes.htm
After this process, assign the new Yearly Shape as a load profile for your electric generation module.

With regards the results you are seeing, the Requirements screen shows the amount of energy a given Transformation module is asked to produce. For your example, the Requirements screen shows how much electricity the electricity generation module is required to produce.

The Outputs by Output Fuel results shows the amount of energy produced by a given Transformation module. Based on the results you provided, the requirements appear to be equal to the outputs for all years except 2015. I believe that LEAP is not calculating the results for 2015 because the electricity produced in this year is based on the data you inputted in the Historical Production variable. I'm assuming that you set the First Simulation Year in the electricity generation module to 2016, which means that LEAP is calculating the outputs for 2016 onwards. For these years, LEAP calculates the outputs to try and meet the electricity requirements for the module. If you think that the outputs for 2016 onwards should be higher, you will need to adjust the electricity generation requirements. To adjust the electricity generation requirements, check the electricity demands entered in the Demand branches, the electricity export targets set in the electricity generation module, and any the electricity demands from the modules above the electricity generation module.

Hope this helps!

Emily