Make a vanilla mob farm that kills from height damage.
Build an LXP Collector and place it in the middle of the kill zone.
Add one fluiduct and connect an LXP Catalyzer then add one Fluiduct to the bottom of the LXP Catalyzer.
Add a tank right next the the LXP Catalyzer and connect the bottom Fluiduct from the the LXP Catalyzer to the tank.
Now, connect the top of the tank to the top Fluiduct of the LXP Catalyzer so that the tank and the LXP Catalyzer create a closed loop with the LXP Collecter at the top. all 3 should be connected in a closed loop using 4 Fluiducts. At the botton of the tank use a Crescent Hammer and right-click the Fluiduct until it has a red arrow..
You will need to use a Pnuematic Servo to "power" the Fluiduct so add it by right-clicking the pipe with it in your hand and then with an empty hand click the pipe again and a UI will appear then on the right side of the UI there will red square (with a picture of redstone dust) that you can click. It is labeled as Redstone Control. Your going to want to click the icon that has a picture of gunpower or "Disabled". Once you do that the dark red arrow will become bright red and you will now be able to power the LXP Catalyzer.
Now that the primary part is done you will be able to produce an infinite amount of LXP. To access this LXP you will need to connect Fluiducts to the Fluiduct that is on the top of the tank that is connected to the LXP Catalyzer and the LXP Collector then connect more Fluiduct to some storage tanks.
To create energy construct some Compression Dynamos and an Aqueous Accumulator. Place the Aqueous Accumulator in the middle of a 1x3 hole then fill the sides with water so that there is water on both sides of the Aqueous Accumulator. Attach Fluiducts to the top of the Aqueous Accumulator and pipe water into your Compression Dynamos.
Compression Dynamos need a fuel and a coolant. We will use the LXP as Fuel and water as Coolant.
To increase your LXP yields exponentually add spawners to your mob farm. AFK near your spawners for about 30 minutes and your tanks will be filled in no time.
You will have a ton of drops from this so you will want to collect them with an Item Collector. The Advanced Item Collector has custom settings that allow you to define the X,Y,Z distance to collect items but has a bug where all settings are reset to the X value when you log off so you will need to reset the settings every time you log in. A vaccuum hopper would work better overall if you can find a place to fit it but it will absorb some XP orbs and convert it to Open Blocks Exp.