diff --git a/prometheus-exporter/README.md b/prometheus-exporter/README.md
index a5b4443..3a55e89 100644
--- a/prometheus-exporter/README.md
+++ b/prometheus-exporter/README.md
@@ -9,6 +9,9 @@ Currently, item and fluid production metrics are available:
 `factorio_(production/consumption)_total`
 : Gives a counter of item and fluid production or consumption, including the *type* (item or fluid), *surface* (a.k.a. planet), *force* (usually player), and the in-game name of the entity.
 
+`factorio_energy_(production/consumption)_total_joules`
+: Total of item and fluid production or consumption, including the *network_id*, *surface* and *name* of the entity using or producing power. Note that the player must place a **Metrics Pole** in the electricity network to track its metrics (to avoid tracking very many tiny networks).
+
 ## Usage
 
 The mod alone cannot do everything in-game, nor do you want it to, for performance reasons. As such, it does the absolute minimum amount of work necessary to get the metrics onto your filesystem. From here, a sidecar exposes it to Prometheus.