It is unclear whether you want to perform Life Cycle Assessment (LCA) or Life Cycle Cost assessment (LCC). I think you mean the latter, then previous answers arent applicable as they describe LCA.
I believe the above answers are right if you want to assess LCA. but if you are considering LCC then you have to incorporate various costs involved. for example:
Initial Costs—Purchase, Acquisition, Construction Costs (cost of ownership)
Fuel Costs and energy cost
Operation, Maintenance, and Repair Costs
Replacement Costs, refurbishing costs
Residual Values—Resale or Salvage Values or Disposal or end -of-life treatment Costs
Finance Charges—Loan Interest Payments
If you ready with all the data you can perform the LCC easily.