Redstone Energy Conduit
Redstone Energy Conduits lose 5 percent of their carried power regardless of distance. The loss occurs at each point the conduit is connected to an object that pulls power (e.g. machines or Redstone Energy Cells).
Unlike conductive Buildcraft pipes in 1.4.7, Redstone Energy Conduits cannot blow up from an overflow of energy. Also, they are an attractive alternative to conductive Buildcraft pipes when the distance travelled is more than 10 blocks compared to Gold Conductive Pipes (which have a 0.5% energy loss), or more than 1 block compared to Stone Conductive Pipes (which have 5% energy loss).
Note: In Buildcraft 4 there is no enegy loss at all when you use Conductive Pipes.
For those interested in transporting MJ, here is an alternate (lossless) method:
Note: Be aware that if you charge a Redstone Energy Cell as shown in the video, the cell won't take all the MJ produced by the engines (even if the Cells input is 100MJ)! The not used energy is stored within the engine and will cause the engine to overheat! A 99.5% method without overheating engines would be: Engine(s) => Wooden conductive pipe => Golden conductive pipe => BC Consumer => Energy Bridge => Steam Producer => Liquid Tesseract || whatever distance || Liquid Tesseract => Steam Consumer => Energy Bridge => BC Producer => machine (e.g. quarry).
Using a wrench on a length of conduit that is adjacent to something producing or consuming energy will toggle its mode - input-only or output-only. The arrows on the conduit plugs should be self-explanatory. This affects the entire conduit and cannot be changed per "side". *To save confusion, (Blue = Input) (Orange=Output)
Also keep in mind that, unlike Wooden Conductive Pipes, Redstone Energy Conduits cannot have an input and output in the same block. This makes it easier to collect energy from multiple blocks, which Wooden Conductive Pipes cannot do.
These blocks are somewhat robust. If dismantled (Sneak + Activate) with a BuildCraft compatible Wrench or Crescent Hammer, they will instantly be removed.
WARNING FOR USERS OF REDPOWER
Do not attempt to move this block with Frames. This may cause a chunk reset or worse.
Interaction with Gates: Redstone Energy Conduit appears to act like a machine that can store energy, having the ability to send signals such as Capacitor Fully Charged to a neighboring gate. This is probably intentional. However, the conduit appears to always be at least "partially charged" if it has ever carried a charge. In order to detect if a machine is holding a charge, the gate must be placed so that it is not adjacent to any of the conduit supplying or draining the machine.