diff --git a/core/net/rpl/rpl-icmp6.c b/core/net/rpl/rpl-icmp6.c
index be919fadb..1bc70dd0f 100644
--- a/core/net/rpl/rpl-icmp6.c
+++ b/core/net/rpl/rpl-icmp6.c
@@ -250,9 +250,10 @@ dio_input(void)
       dio.mc.aggr = buffer[i + 4] >> 4;
       dio.mc.prec = buffer[i + 4] & 0xf;
       dio.mc.length = buffer[i + 5];
+
       if(dio.mc.type == RPL_DAG_MC_ETX) {
-        dio.mc.etx.etx = buffer[i + 6] << 8;
-        dio.mc.etx.etx |= buffer[i + 7];
+        dio.mc.obj.etx = buffer[i + 6] << 8;
+        dio.mc.obj.etx |= buffer[i + 7];
 
         PRINTF("RPL: DAG MC: type %u, flags %u, aggr %u, prec %u, length %u, ETX %u\n",
 	       (unsigned)dio.mc.type,  
@@ -260,7 +261,10 @@ dio_input(void)
 	       (unsigned)dio.mc.aggr, 
 	       (unsigned)dio.mc.prec, 
 	       (unsigned)dio.mc.length, 
-	       (unsigned)dio.mc.etx.etx);
+	       (unsigned)dio.mc.obj.etx);
+      } else if(dio.mc.type == RPL_DAG_MC_ENERGY) {
+        dio.mc.obj.energy.flags = buffer[i + 6];
+        dio.mc.obj.energy.energy_est = buffer[i + 7];
       } else {
        PRINTF("RPL: Unhandled DAG MC type: %u\n", (unsigned)dio.mc.type);
        return;
@@ -380,8 +384,12 @@ dio_output(rpl_dag_t *dag, uip_ipaddr_t *uc_addr)
     buffer[pos++] |= dag->mc.prec;
     if(dag->mc.type == RPL_DAG_MC_ETX) {
       buffer[pos++] = 2;
-      buffer[pos++] = dag->mc.etx.etx >> 8;
-      buffer[pos++] = dag->mc.etx.etx & 0xff;
+      buffer[pos++] = dag->mc.obj.etx >> 8;
+      buffer[pos++] = dag->mc.obj.etx & 0xff;
+    } else if(dag->mc.type == RPL_DAG_MC_ENERGY) {
+      buffer[pos++] = 2;
+      buffer[pos++] = dag->mc.obj.energy.flags;
+      buffer[pos++] = dag->mc.obj.energy.energy_est;
     } else {
       PRINTF("RPL: Unable to send DIO because of unhandled DAG MC type %u\n",
 	(unsigned)dag->mc.type);
diff --git a/core/net/rpl/rpl-of-etx.c b/core/net/rpl/rpl-of-etx.c
index e8ffefe1b..0b6265311 100644
--- a/core/net/rpl/rpl-of-etx.c
+++ b/core/net/rpl/rpl-of-etx.c
@@ -66,7 +66,7 @@ rpl_of_t rpl_of_etx = {
 
 #define NI_ETX_TO_RPL_ETX(etx)						\
 	((etx) * (RPL_DAG_MC_ETX_DIVISOR / NEIGHBOR_INFO_ETX_DIVISOR))
-#define RPL_ETX_TO_NI_ETX(etx)						\
+#define rpl_path_metric_tO_NI_ETX(etx)						\
 	((etx) / (RPL_DAG_MC_ETX_DIVISOR / NEIGHBOR_INFO_ETX_DIVISOR))
 
 /* Reject parents that have a higher link metric than the following. */
@@ -84,13 +84,12 @@ rpl_of_t rpl_of_etx = {
  */
 #define PARENT_SWITCH_THRESHOLD_DIV	2
 
-typedef uint16_t rpl_etx_t;
-#define MAX_ETX 65535
+typedef uint16_t rpl_path_metric_t;
 
 static uint16_t
-calculate_etx(rpl_parent_t *p)
+calculate_path_metric(rpl_parent_t *p)
 {
-  return p->mc.etx.etx + NI_ETX_TO_RPL_ETX(p->etx);
+  return p->mc.obj.etx + NI_ETX_TO_RPL_ETX(p->etx);
 }
 
 static void
@@ -140,48 +139,64 @@ static rpl_parent_t *
 best_parent(rpl_parent_t *p1, rpl_parent_t *p2)
 {
   rpl_dag_t *dag;
-  rpl_etx_t min_diff;
-  rpl_etx_t p1_etx;
-  rpl_etx_t p2_etx;
+  rpl_path_metric_t min_diff;
+  rpl_path_metric_t p1_metric;
+  rpl_path_metric_t p2_metric;
 
   dag = p1->dag; /* Both parents must be in the same DAG. */
 
   min_diff = RPL_DAG_MC_ETX_DIVISOR / 
              PARENT_SWITCH_THRESHOLD_DIV;
 
-  p1_etx = calculate_etx(p1);
-  p2_etx = calculate_etx(p2);
+  p1_metric = calculate_path_metric(p1);
+  p2_metric = calculate_path_metric(p2);
 
   /* Maintain stability of the preferred parent in case of similar ranks. */
   if(p1 == dag->preferred_parent || p2 == dag->preferred_parent) {
-    if(p1_etx < p2_etx + min_diff &&
-       p1_etx > p2_etx - min_diff) {
+    if(p1_metric < p2_metric + min_diff &&
+       p1_metric > p2_metric - min_diff) {
       PRINTF("RPL: MRHOF hysteresis: %u <= %u <= %u\n",
-             p2_etx - min_diff,
-             p1_etx,
-             p2_etx + min_diff);
+             p2_metric - min_diff,
+             p1_metric,
+             p2_metric + min_diff);
       return dag->preferred_parent;
     }
   }
 
-  return p1_etx < p2_etx ? p1 : p2;
+  return p1_metric < p2_metric ? p1 : p2;
 }
 
 static void
 update_metric_container(rpl_dag_t *dag)
 {
+#if RPL_DAG_MC == RPL_DAG_MC_ETX
   dag->mc.type = RPL_DAG_MC_ETX;
   dag->mc.flags = RPL_DAG_MC_FLAG_P;
   dag->mc.aggr = RPL_DAG_MC_AGGR_ADDITIVE;
   dag->mc.prec = 0;
-  dag->mc.length = sizeof(dag->mc.etx.etx);
+  dag->mc.length = sizeof(dag->mc.obj.etx);
   if(dag->rank == ROOT_RANK(dag)) {
-    dag->mc.etx.etx = 0;
+    dag->mc.obj.etx = 0;
   } else {
-    dag->mc.etx.etx = calculate_etx(dag->preferred_parent);
+    dag->mc.obj.etx = calculate_path_metric(dag->preferred_parent);
   }
+#elif RPL_DAG_MC == RPL_DAG_MC_ENERGY
+  dag->mc.type = RPL_DAG_MC_ENERGY;
+  dag->mc.flags = RPL_DAG_MC_FLAG_P;
+  dag->mc.aggr = RPL_DAG_MC_AGGR_ADDITIVE;
+  dag->mc.prec = 0;
+  dag->mc.length = sizeof(dag->mc.obj.energy);
+  if(dag->rank == ROOT_RANK(dag)) {
+    dag->mc.obj.energy.flags = RPL_DAG_MC_ENERGY_TYPE_MAINS << RPL_DAG_MC_ENERGY_TYPE;
+  } else {
+    dag->mc.obj.energy.flags = RPL_DAG_MC_ENERGY_TYPE_BATTERY << RPL_DAG_MC_ENERGY_TYPE;
+  }
+  dag->mc.obj.energy.energy_est = calculate_path_metric(dag->preferred_parent);
+#else
+#error "Unsupported RPL_DAG_MC configured. See rpl.h."
+#endif /* RPL_DAG_MC */
 
   PRINTF("RPL: My path ETX to the root is %u.%u\n",
-	dag->mc.etx.etx / RPL_DAG_MC_ETX_DIVISOR,
-	(dag->mc.etx.etx % RPL_DAG_MC_ETX_DIVISOR * 100) / RPL_DAG_MC_ETX_DIVISOR);
+	dag->mc.obj.etx / RPL_DAG_MC_ETX_DIVISOR,
+	(dag->mc.obj.etx % RPL_DAG_MC_ETX_DIVISOR * 100) / RPL_DAG_MC_ETX_DIVISOR);
 }
diff --git a/core/net/rpl/rpl.h b/core/net/rpl/rpl.h
index 17a1845ec..5676ccd31 100644
--- a/core/net/rpl/rpl.h
+++ b/core/net/rpl/rpl.h
@@ -49,6 +49,17 @@
 #define RPL_CONF_STATS 0
 #endif /* RPL_CONF_STATS */
 
+/* 
+ * Select routing metric supported at runtime. This must be a valid
+ * DAG Metric Container Object Type (see below). Currently, we only 
+ * support RPL_DAG_MC_ETX and RPL_DAG_MC_ENERGY.
+ */
+#ifdef RPL_CONF_DAG_MC
+#define RPL_DAG_MC RPL_CONF_DAG_MC
+#else
+#define RPL_DAG_MC RPL_DAG_MC_ETX
+#endif /* RPL_CONF_DAG_MC */
+
 /*
  * The objective function used by RPL is configurable through the 
  * RPL_CONF_OF parameter. This should be defined to be the name of an 
@@ -78,8 +89,8 @@ typedef uint16_t rpl_ocp_t;
 /* DAG Metric Container Object Types, to be confirmed by IANA. */
 #define RPL_DAG_MC_NONE			0 /* Local identifier for empty MC */
 #define RPL_DAG_MC_NSA                  1 /* Node State and Attributes */
-#define RPL_DAG_MC_NE                   2 /* Node Energy */
-#define RPL_DAG_MC_HC                   3 /* Hop Count */
+#define RPL_DAG_MC_ENERGY               2 /* Node Energy */
+#define RPL_DAG_MC_HOPCOUNT             3 /* Hop Count */
 #define RPL_DAG_MC_THROUGHPUT           4 /* Throughput */
 #define RPL_DAG_MC_LATENCY              5 /* Latency */
 #define RPL_DAG_MC_LQL                  6 /* Link Quality Level */
@@ -99,9 +110,19 @@ typedef uint16_t rpl_ocp_t;
 #define RPL_DAG_MC_AGGR_MINIMUM         2
 #define RPL_DAG_MC_AGGR_MULTIPLICATIVE  3
 
-/* Logical representation of an ETX object in a DAG Metric Container. */
-struct rpl_metric_object_etx {
-  uint16_t etx;
+/* The bit index within the flags field of
+   the rpl_metric_object_energy structure. */
+#define RPL_DAG_MC_ENERGY_INCLUDED	3
+#define RPL_DAG_MC_ENERGY_TYPE		1
+#define RPL_DAG_MC_ENERGY_ESTIMATION	0
+
+#define RPL_DAG_MC_ENERGY_TYPE_MAINS		0
+#define RPL_DAG_MC_ENERGY_TYPE_BATTERY		1
+#define RPL_DAG_MC_ENERGY_TYPE_SCAVENGING	2
+
+struct rpl_metric_object_energy {
+  uint8_t flags;
+  uint8_t energy_est;
 };
 
 /* Logical representation of a DAG Metric Container. */
@@ -111,9 +132,10 @@ struct rpl_metric_container {
   uint8_t aggr;
   uint8_t prec;
   uint8_t length;
-  /* Once we support more objects, the etx field will be replaced by a
-     union of those. */
-  struct rpl_metric_object_etx etx;
+  union metric_object {
+    struct rpl_metric_object_energy energy;
+    uint16_t etx;
+  } obj;
 };
 typedef struct rpl_metric_container rpl_metric_container_t;
 /*---------------------------------------------------------------------------*/