# Optimization with import unmet requirement

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Userlevel 2
+4
• Ace
• 30 replies

Dear All,

I'm designing an optimization model to determine the power generation capacity from local energy sources. If the local energy sources are not sufficient, the need for electrical energy that cannot be met from local energy sources is met by importing electrical energy from other regions.

I'm currently using an imported electrical energy variable (Imp_Electricity) in the energy balance constraint function. However, after using the price of imported electrical energy, the optimization results show that all electrical energy needs are met by imported electrical energy and no generating capacity is required. This is because importing electrical energy is cheaper than having to build a power plant. And when the Imp_Electricity variable is assigned a value of ZERO, the model is not feasible because the energy balance constraint function is violated.

The result I expect from the model that I am currently designing is that the model can prioritize the construction of power plants to determine how much electrical energy needs can be met by optimizing local energy sources.

How to design the model as I expect with AIMMS?

Thank you.

### 2 replies

Userlevel 5
+7

Hello Rahmat,

This is an interesting modeling question that leads to various other questions:

1. how do you compare the CAPEX of paying for building a power plant with the OPEX of paying for imported electricity? Are you perhaps using depreciation, or perhaps leasing, or?
2. do you take the energy loss, perhaps just a few percent, into account of transporting energy?
3. do you take into account the value of energy independence? (how much does the region a new power plant should service value being independent of outside energy sources)?

With kind regards,

Chris.

Userlevel 2
+4

Hello @Chris Kuip ,

The answers to these questions are:

1. The investment costs and operating costs of power generation units are calculated using the Capital Recovery Factor.
2. Energy losses that are calculated are losses in transmission and distribution lines of electrical energy (about 8%).
3. The independence factor in the supply of electrical energy has not been included in the model being developed.

So, by including the independence factor in energy supply, can the priority of power plant development take precedence over imports?

Thank you very much.