A tesseract can feed a geothermal just by touching it. You can also use Fluid ducts from thermal expansion. If you want to use BC pipes, put a BC tank next to the tesseract and it should auto fill it. Then you can use a wooden pipe to pull it from the tank. Not sure what mod pack you are using, but if you have extra utilities, a liquid transfer node on the tesseract and transfer pipes carrying the lava where you need it should also work.
I generally use ender tanks instead of tesseracts for lava. They can auto eject into any pipes so you don't need wooden pipes or servos for TE3 ducts.