diff --git a/prometheus-exporter/README.md b/prometheus-exporter/README.md
index a5b4443..e8b0771 100644
--- a/prometheus-exporter/README.md
+++ b/prometheus-exporter/README.md
@@ -8,6 +8,8 @@ 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