Initialize numeric value of an object

Question

i am trying to do things with a model (written in python and solved with pyomo and guroby) in which i have several costs calculated in this form:

cost_i=sum(M.VariableCost[technology,year]*M.V_Activity[technology,year])

Where M.V_Activity is a model decision variable and the cost is the sum for each technology and year defined in the model.

The objective function, is the sum of several costs, in this form:

economic_cost = cost_i+ cost_j+ cost_x

I want to add an other term to the function, this will be called "environmental cost" and will have the same order of magnitude of the "economic cost", because i want the new term to have a weight comparable to the others in the final objective function, that will be written in the form:

final_cost = economic_cost+ENVIRONMENTAL_COST

I'm trying to establish the order of magnitude of economic_cost trough a cycle,in order to find the exponent that i have to apply at the Environmental_cost in order to make it count, the cycle is in this form:

if value(economic_cost) >10:
...do things
else:
...do others

The model raise the error:

No value for uninitialized NumericValue object V_Capacity [...]

Where V_Capacity is the term that appears in the cost formulation i have written above (the first one).

I know the problem is in the if value() row ,since when i call the value of the economic_cost, this has not been calculated yet. I would need something that act as a placeholder until a value is defined, but really don't know what to do.

Someone knows how to solve and to let the model run?