Every device on a network draws energy from the 
Controller every tick. The controller takes Forge Energy (FE) from any generator touching it and holds 1,000 FE itself. If the generator cannot keep up, the network shuts down until there is energy again.
The values of Refined Storage's default settings (refinedstorage-common.toml), per tick:
| Device | Energy use |
|---|---|
| Cable | 0 |
| Disk Drive | 10, plus 4 per disk inside |
| Disk Interface | 6, plus 4 per disk inside |
| Grid | 10 |
| Crafting Grid, Pattern Grid | 14 |
| 1k / 4k / 16k / 64k Storage Block | 2 / 4 / 6 / 8 |
| Importer, Exporter, Detector | 2 |
| Constructor, Destructor | 3 |
| Interface, Storage Monitor | 4 |
| External Storage | 6 |
| Network Receiver | 8 |
| Wireless Transmitter, Security Manager, Autocrafter Manager, Autocrafting Monitor | 16 |
| Network Transmitter | 32 |
| Autocrafter | 4, plus 2 per pattern |
| Speed Upgrade / Stack Upgrade | 4 / 16 more on the device |
Our Your First Refined Storage Network — controller, two cables, a disk drive with one 1k disk, a grid and an importer — should draw 10 + 4 + 10 + 2 = 26 by this table. Measured from the controller's buffer on our test server it drew about 24 FE per tick; the draw is not exactly the same from tick to tick.
ControllerBlock
Disk DriveBlock
GridBlock
ImporterBlock
Wireless TransmitterBlock
Network TransmitterBlockNote The 
Creative Controller needs no energy at all (creative mode).
Creative Controller needs no energy at all (creative mode).