diff --git a/prepshot/model.py b/prepshot/model.py
index b15dea8..f1417a9 100644
--- a/prepshot/model.py
+++ b/prepshot/model.py
@@ -96,20 +96,15 @@ def define_variables(model, para):
     """
     model.cost = Var(within=NonNegativeReals, doc='total cost of system [dollar]')
     model.cost_var = Var(within=NonNegativeReals, doc='Variable O&M costs [dollar]')
-    # model.cost_var_breakdown = Var(model.year_zone_tech_tuples, within=NonNegativeReals, doc='Variable O&M costs of each technology [dollar]')
     model.cost_fix = Var(within=NonNegativeReals, doc='Fixed O&M costs [dollar/MW/year]')
-    # model.cost_fix_breakdown = Var(model.year_zone_tech_tuples, within=NonNegativeReals, doc='Fixed O&M costs of each technology [dollar/MW/year]')
     model.cost_newtech = Var(within=NonNegativeReals, doc='Investment costs of new technology [dollar]')
-    # model.cost_newtech_breakdown = Var(model.year_zone_tech_tuples, within=NonNegativeReals, doc='Investment costs of new technology [dollar]')
     model.cost_newline = Var(within=NonNegativeReals, doc='Investment costs of new transmission lines [dollar]')
-    # model.cost_newline_breakdown = Var(model.year_zone_zone_tuples, within=NonNegativeReals, doc='Investment costs of new transmission lines [dollar]')
     model.income = Var(within=NonNegativeReals, doc='total income of withdraw water [dollar]')
     model.cap_existing = Var(model.year_zone_tech_tuples, within=NonNegativeReals, doc='Capacity of existing technology [MW]')
     model.cap_newtech = Var(model.year_zone_tech_tuples, within=NonNegativeReals, doc='Capacity of newbuild technology [MW]')
     model.cap_newline = Var(model.year_zone_zone_tuples, within=NonNegativeReals, doc='Capacity of new transmission lines [MW]')
     model.cap_lines_existing = Var(model.year_zone_zone_tuples, within=NonNegativeReals, doc='Capacity of existing transmission line [MW]')
     model.carbon = Var(model.year, within=NonNegativeReals, doc='Total carbon dioxide emission in each years [tonne]')
-    # model.carbon_breakdown = Var(model.year_zone_tech_tuples, within=NonNegativeReals, doc='Carbon dioxide emission of each technology [tonne]')
     model.carbon_capacity = Var(model.year_zone_tuples, within=NonNegativeReals, doc='Carbon dioxide emission in each year and each zone [tonne]')
     model.gen = Var(model.hour_month_year_zone_tech_tuples, within=NonNegativeReals, doc='Output of each technology in each year, each zone and each time period [MWh]')
     model.storage = Var(model.hour_p_month_year_zone_tech_tuples, within=NonNegativeReals, doc='Storage of energy technology in each year, each zone and each time period [MW]')