diff --git a/power/Power.tcl b/power/Power.tcl
index 420a97a99..6e2132e33 100644
--- a/power/Power.tcl
+++ b/power/Power.tcl
@@ -35,13 +35,14 @@ define_cmd_args "report_power" \
       [-highest_power_instances count]\
       [-corner corner]\
       [-digits digits]\
+      [-format format]\
       [> filename] [>> filename] }
 
 proc_redirect report_power {
   global sta_report_default_digits
 
   parse_key_args "report_power" args \
-    keys {-instances -highest_power_instances -corner -digits} flags {}
+    keys {-instances -highest_power_instances -corner -digits -format} flags {}
 
   check_argc_eq0 "report_power" $args
 
@@ -56,19 +57,39 @@ proc_redirect report_power {
   }
   set corner [parse_corner keys]
 
+  if { ![info exists keys(-format)] } {
+    set keys(-format) "text"
+  }
+  if { $keys(-format) != "text" && $keys(-format) != "json"  } {
+    sta_error 311 "unknown power report -format $keys(-format)"
+  }
+
   if { [info exists keys(-instances)] } {
     set insts [get_instances_error "-instances" $keys(-instances)]
-    report_power_insts $insts $corner $digits
+    report_power_insts $insts $corner $digits $keys(-format)
   } elseif { [info exists keys(-highest_power_instances)] } {
     set count $keys(-highest_power_instances)
     check_positive_integer "-highest_power_instances" $count
     set insts [highest_power_instances $count $corner]
-    report_power_insts $insts $corner $digits
+    report_power_insts $insts $corner $digits $keys(-format)
   } else {
-    report_power_design $corner $digits
+    report_power_design $corner $digits $keys(-format)
+  }
+}
+
+define_cmd_args "report_internal_power_components" { [> filename] [>> filename] }
+proc_redirect report_internal_power_components {
+  global sta_report_default_digits
+  # Set the default corner
+  set corner [cmd_corner]
+  if { ![liberty_libraries_exist] } {
+    sta_error 304 "No liberty libraries have been read."
   }
+  set power_result [internal_power_components $corner]
+  report_line $power_result
 }
 
+
 proc liberty_libraries_exist {} {
   set lib_iter [liberty_library_iterator]
   set have_liberty 0
@@ -79,7 +100,7 @@ proc liberty_libraries_exist {} {
   return $have_liberty
 }
 
-proc report_power_design { corner digits } {
+proc report_power_design { corner digits {report_format "text"} } {
   set power_result [design_power $corner]
   set totals        [lrange $power_result  0  3]
   set sequential    [lrange $power_result  4  7]
@@ -90,18 +111,29 @@ proc report_power_design { corner digits } {
   lassign $totals design_internal design_switching design_leakage design_total
 
   set field_width [max [expr $digits + 6] 10]
-  report_power_title5       "Group" "Internal" "Switching" "Leakage" "Total" $field_width
-  report_power_title5_units "     " "Power"    "Power"     "Power"   "Power" "(Watts)" $field_width
-  report_title_dashes5 $field_width
-  report_power_row "Sequential"    $sequential    $design_total $field_width $digits
-  report_power_row "Combinational" $combinational $design_total $field_width $digits
-  report_power_row "Clock"         $clock         $design_total $field_width $digits
-  report_power_row "Macro"         $macro         $design_total $field_width $digits
-  report_power_row "Pad"           $pad           $design_total $field_width $digits
-  report_title_dashes5 $field_width
-  report_power_row "Total" $power_result $design_total $field_width $digits
-
-  report_line "[format %-20s {}][power_col_percent $design_internal  $design_total $field_width][power_col_percent $design_switching $design_total $field_width][power_col_percent $design_leakage $design_total $field_width]"
+  if { $report_format == "text" } {
+    report_power_title5       "Group" "Internal" "Switching" "Leakage" "Total" $field_width
+    report_power_title5_units "     " "Power"    "Power"     "Power"   "Power" "(Watts)" $field_width
+    report_title_dashes5 $field_width
+  } elseif { $report_format == "json" } {
+    report_line "\{"
+  }
+
+  set last_row_var ""
+  report_power_row "Sequential"    $sequential    $design_total $field_width $digits $report_format last_row_var
+  report_power_row "Combinational" $combinational $design_total $field_width $digits $report_format last_row_var
+  report_power_row "Clock"         $clock         $design_total $field_width $digits $report_format last_row_var
+  report_power_row "Macro"         $macro         $design_total $field_width $digits $report_format last_row_var
+  report_power_row "Pad"           $pad           $design_total $field_width $digits $report_format last_row_var
+  if { $report_format == "text" } {
+    report_title_dashes5 $field_width
+  }
+  report_power_row "Total" $power_result $design_total $field_width $digits $report_format last_row_var
+  if { $report_format == "text" } {
+    report_line "[format %-20s {}][power_col_percent $design_internal  $design_total $field_width][power_col_percent $design_switching $design_total $field_width][power_col_percent $design_leakage $design_total $field_width]"
+  } elseif { $report_format == "json" } {
+    report_line "\}"
+  }
 }
 
 proc max { x y } {
@@ -146,14 +178,28 @@ proc report_title_dashes { count } {
   report_line $line
 }
 
-proc report_power_row { type row_result design_total field_width digits } {
+proc report_power_row { type row_result design_total field_width digits {report_format "text"} {last_row_var ""} } {
   lassign $row_result internal switching leakage total
   if { $design_total == 0.0 || [is_nan $design_total] } {
     set percent 0.0
   } else {
     set percent [expr $total / $design_total * 100]
   }
-  report_line "[format %-20s $type][power_col $internal $field_width $digits][power_col $switching $field_width $digits][power_col $leakage $field_width $digits][power_col $total $field_width $digits] [format %5.1f $percent]%"
+  if { "$report_format" == "json" } {
+    upvar_opt 1 $last_row_var last_row
+    if { $last_row != "" } {
+      report_line "  ,"
+    }
+    report_line "  \"$type\": {"
+    report_line "    \"internal\":[power_col $internal $field_width $digits],"
+    report_line "    \"switching\":[power_col $switching $field_width $digits],"
+    report_line "    \"leakage\":[power_col $leakage $field_width $digits],"
+    report_line "    \"total\":[power_col $total $field_width $digits]"
+    report_line "  }"
+    set last_row $type
+  } else {
+    report_line "[format %-20s $type][power_col $internal $field_width $digits][power_col $switching $field_width $digits][power_col $leakage $field_width $digits][power_col $total $field_width $digits] [format %5.1f $percent]%"
+  }
 }
 
 proc is_nan { str } {
@@ -185,7 +231,7 @@ proc report_power_line { type pwr digits } {
   }
 }
 
-proc report_power_insts { insts corner digits } {
+proc report_power_insts { insts corner digits {report_format "text"} } {
   set inst_pwrs {}
   foreach inst $insts {
     set power_result [instance_power $inst $corner]
@@ -195,14 +241,23 @@ proc report_power_insts { insts corner digits } {
 
   set field_width [max [expr $digits + 6] 10]
 
-  report_power_title4       "Internal" "Switching" "Leakage" "Total" $field_width
-  report_power_title4_units "Power"    "Power"     "Power"   "Power" "(Watts)" $field_width
-  report_title_dashes4 $field_width
+  if { $report_format == "text" } {
+    report_power_title4       "Internal" "Switching" "Leakage" "Total" $field_width
+    report_power_title4_units "Power"    "Power"     "Power"   "Power" "(Watts)" $field_width
+    report_title_dashes4 $field_width
+  } else {
+    report_line {[}
+  }
 
+  set last_inst_var ""
   foreach inst_pwr $inst_pwrs {
     set inst [lindex $inst_pwr 0]
     set power [lindex $inst_pwr 1]
-    report_power_inst $inst $power $field_width $digits
+    report_power_inst $inst $power $field_width $digits $report_format last_inst_var
+  }
+  
+  if { $report_format == "json" } {
+    report_line {]}
   }
 }
 
@@ -220,9 +275,24 @@ proc inst_pwr_cmp { inst_pwr1 inst_pwr2 } {
   }
 }
 
-proc report_power_inst { inst power_result field_width digits } {
+proc report_power_inst { inst power_result field_width digits {report_format "text"} {last_inst_var ""}} {
   lassign $power_result internal switching leakage total
-  report_line "[power_col $internal $field_width $digits][power_col $switching $field_width $digits][power_col $leakage $field_width $digits][power_col $total $field_width $digits] [get_full_name $inst]"
+  if { $report_format == "json" } {
+    upvar_opt 1 $last_inst_var last_inst
+    if { $last_inst != "" } {
+      report_line ","
+    }
+    report_line "{"
+    report_line "  \"name\": \"[get_full_name $inst]\","
+    report_line "  \"internal\":[power_col $internal $field_width $digits],"
+    report_line "  \"switching\":[power_col $switching $field_width $digits],"
+    report_line "  \"leakage\":[power_col $leakage $field_width $digits],"
+    report_line "  \"total\":[power_col $total $field_width $digits]"
+    report_line "}"
+    set last_inst $inst
+  } elseif { $report_format == "text" }  {
+    report_line "[power_col $internal $field_width $digits][power_col $switching $field_width $digits][power_col $leakage $field_width $digits][power_col $total $field_width $digits] [get_full_name $inst]"
+  }
 }
 
 ################################################################
@@ -287,7 +357,7 @@ proc set_power_activity { args } {
   if { [info exists keys(-input_ports)] } {
     set ports [get_ports_error "input_ports" $keys(-input_ports)]
     foreach port $ports {
-      if { [get_property $port "direction"] == "input" } {
+      if { [get_property $port "direction"] == "input" || [get_property $port "direction"] == "in" } {
 	if { [is_clock_src [sta::get_port_pin $port]] } {
           sta_warn 310 "activity cannot be set on clock ports."
         } else {
diff --git a/tcl/Util.tcl b/tcl/Util.tcl
index 0cb2083bf..ad47cdce2 100644
--- a/tcl/Util.tcl
+++ b/tcl/Util.tcl
@@ -185,6 +185,17 @@ proc define_hidden_cmd_args { cmd arglist } {
   namespace export $cmd
 }
 
+# "Optional Upvar"
+# If $other_var is not empty, the upvar is executed.
+# Otherwise, $my_var is set to empty.
+proc upvar_opt { level other_var my_var } {
+  if { $other_var != "" } {
+    uplevel 1 "upvar $level $other_var $my_var"
+  } else {
+    uplevel 1 "set $my_var \"\""
+  }
+}
+
 ################################################################
 
 proc sta_warn { msg_id msg } {
diff --git a/test/power_json.tcl b/test/power_json.tcl
new file mode 100644
index 000000000..2a770364b
--- /dev/null
+++ b/test/power_json.tcl
@@ -0,0 +1,24 @@
+# report_power reg1_asap7
+set sta_report_default_digits 4
+read_liberty ../examples/asap7_small.lib.gz
+read_verilog ../examples/reg1_asap7.v
+link_design top
+
+create_clock -name clk1 -period 500 clk1
+create_clock -name clk2 -period 500 clk2
+create_clock -name clk3 -period 500 clk3
+
+set_input_delay -clock clk1 1 {in1 in2}
+set_input_delay -clock clk2 1 {in1 in2}
+set_input_delay -clock clk3 1 {in1 in2}
+set_input_transition 10 {in1 in2 clk1 clk2 clk3}
+
+set_propagated_clock {clk1 clk2 clk3}
+
+read_spef ../examples/reg1_asap7.spef
+
+set_power_activity -input -activity .1
+set_power_activity -input_port reset -activity 0
+
+report_power -format json
+report_power -format json -instances "[get_cells -filter "name=~clkbuf*"]"
\ No newline at end of file