Lava is a liquid in vanilla Minecraft. It is commonly found deep underground at layer 10 and rarely on or near the surface in the form of lava pools or Volcanoes. Lava also appears as large oceans in the Nether. If you right click a block of lava with an Empty Cell, it will consume the lava source block and turn the cell into a Lava Cell. Buckets of Lava can be put into a Geothermal Generator for EU, and you can also suck up lava with a Pump. You can also craft lava source blocks legitimately with UU-Matter.
A lava source block doesn't have any value (EMC), however a Lava Bucket does. Therefore the EMC of a lava source block can be found by substracting the EMC of a Bucket (768) with the EMC of a Lava Bucket (832) which is equal to 64 EMC per lava source block.
This recipe creates a still lava block, allowing for stationary lava lamps.