Complex sentence: The Energy Policy Act of 2005 specifically added thermal depolymerization to a $1 renewable diesel credit, which became effective at the end of 2005, allowing a profit of $4/barrel of output oil.
Split into simpler sentences: The Energy Policy Act of 2005 specifically added thermal depolymerization to a $1 renewable diesel credit, which became effective at the end of 2005. A federal subsidy (the Energy Policy Act of 2005) allowed a profit of $4/barrel of output oil.