1. check the compatibility between multi-fuels and piesewise heat rat…

…es when reading generators_data.csv;

2. change i into f in load_generators_data.jl in "for i in 1:max_fuels"

src/load_inputs/load_generators_data.jl

@@ -262,12 +262,12 @@ function load_multi_fuels_data!(inputs_gen::Dict, setup::Dict, path::AbstractStr
 
 	inputs_gen["NUM_FUELS"] = gen_in[!,:Num_Fuels]   # Number of fuels that this resource can use
 	max_fuels = maximum(inputs_gen["NUM_FUELS"])
-	fuel_cols = [ Symbol(string("Fuel",i)) for i in 1:max_fuels ]
-	heat_rate_cols = [ Symbol(string("Heat_Rate",i, "_MMBTU_per_MWh")) for i in 1:max_fuels ]
-	max_cofire_cols = [ Symbol(string("Fuel",i, "_Max_Cofire_Level")) for i in 1:max_fuels ]
-	min_cofire_cols = [ Symbol(string("Fuel",i, "_Min_Cofire_Level")) for i in 1:max_fuels ]
-	max_cofire_start_cols = [ Symbol(string("Fuel",i, "_Max_Cofire_Level_Start")) for i in 1:max_fuels ]
-	min_cofire_start_cols = [ Symbol(string("Fuel",i, "_Min_Cofire_Level_Start")) for i in 1:max_fuels ]
+	fuel_cols = [ Symbol(string("Fuel",f)) for f in 1:max_fuels ]
+	heat_rate_cols = [ Symbol(string("Heat_Rate",f, "_MMBTU_per_MWh")) for f in 1:max_fuels ]
+	max_cofire_cols = [ Symbol(string("Fuel",f, "_Max_Cofire_Level")) for f in 1:max_fuels ]
+	min_cofire_cols = [ Symbol(string("Fuel",f, "_Min_Cofire_Level")) for f in 1:max_fuels ]
+	max_cofire_start_cols = [ Symbol(string("Fuel",f, "_Max_Cofire_Level_Start")) for f in 1:max_fuels ]
+	min_cofire_start_cols = [ Symbol(string("Fuel",f, "_Min_Cofire_Level_Start")) for f in 1:max_fuels ]
 	fuel_types = [ gen_in[!,f] for f in fuel_cols ]
 	heat_rates = [ gen_in[!,f] for f in heat_rate_cols ]
 	max_cofire = [ gen_in[!,f] for f in max_cofire_cols ]
@@ -284,13 +284,19 @@ function load_multi_fuels_data!(inputs_gen::Dict, setup::Dict, path::AbstractStr
 	inputs_gen["MAX_NUM_FUELS"] = max_fuels
 
 	# check whether non-zero heat rates are used for resources that only use a single fuel
-	for i in 1:max_fuels
-		for hr in heat_rates[i][inputs_gen["SINGLE_FUEL"]]
+	for f in 1:max_fuels
+		for hr in heat_rates[f][inputs_gen["SINGLE_FUEL"]]
 			if  hr > 0 
 				error("Heat rates for multi fuels must be zero when only one fuel is used")
 			end
 		end
 	end
+	# do not allow the multi-fuel option when piece-wise heat rates are used
+	THERM_COMMIT_PWFU = inputs_gen["THERM_COMMIT_PWFU"]
+    # segemnt for piecewise fuel usage
+    if !isempty(THERM_COMMIT_PWFU)
+		error("Multi-fuel option is not available when piece-wise heat rates are used. Please remove multi fuels to avoid this error.")
+    end
 end
 
 @doc raw"""

src/model/core/fuel.jl

@@ -258,20 +258,16 @@ function fuel!(EP::Model, inputs::Dict, setup::Dict)
         THERM_COMMIT_PWFU = inputs["THERM_COMMIT_PWFU"]
         # segemnt for piecewise fuel usage
         if !isempty(THERM_COMMIT_PWFU)
-            if isempty(MULTI_FUELS)
-                segs = 1:inputs["PWFU_Num_Segments"]
-                PWFU_data = inputs["PWFU_data"]
-                slope_cols = inputs["slope_cols"]
-                intercept_cols = inputs["intercept_cols"]
-                segment_intercept(y, seg) = PWFU_data[y, intercept_cols[seg]]
-                segment_slope(y, seg) = PWFU_data[y, slope_cols[seg]]
-                # constraint for piecewise fuel consumption
-                @constraint(EP, PiecewiseFuelUsage[y in THERM_COMMIT_PWFU, t = 1:T, seg in segs],
-                EP[:vFuel][y, t] >= (EP[:vP][y, t] *  segment_slope(y, seg) + 
-                EP[:vCOMMIT][y, t] * segment_intercept(y, seg)))
-            else
-                error("Multi-fuel option is not available when piece-wise heat rates are used. Please remove multi fuels to avoid this error.")
-            end
+            segs = 1:inputs["PWFU_Num_Segments"]
+            PWFU_data = inputs["PWFU_data"]
+            slope_cols = inputs["slope_cols"]
+            intercept_cols = inputs["intercept_cols"]
+            segment_intercept(y, seg) = PWFU_data[y, intercept_cols[seg]]
+            segment_slope(y, seg) = PWFU_data[y, slope_cols[seg]]
+            # constraint for piecewise fuel consumption
+            @constraint(EP, PiecewiseFuelUsage[y in THERM_COMMIT_PWFU, t = 1:T, seg in segs],
+            EP[:vFuel][y, t] >= (EP[:vP][y, t] *  segment_slope(y, seg) + 
+            EP[:vCOMMIT][y, t] * segment_intercept(y, seg)))
         end
 
         # constraint for fuel consumption at a constant heat rate