Heating Unit
From Feed The Beast Wiki
The Heating Unit is an upgrade item for the Oven which allows it to use energy from other mods (Redstone Flux, IC2 etc.) to cook, rather than traditional fuel.
Right-click an Oven with the upgrade and it will allow the Oven to store and use energy.
Note: The Oven will not store energy from Immersive Engineering. Other energy mods have not been tested with this.