In 1990 the Ministry of Research and Technology in the FRG proposed a comprehensive concept to sponsor biotechnical and energetical use of agricultural materials. Within this concept various modern Diesel engines have been investigated with respect to performance, fuel consumption, exhaust emissions and durability characteristics using neat (100%) rapeseed oil as fuel. Energy consumption and engine performance are similar to operation with Diesel fuel, exhaust emissions are higher with rapeseed oil. Diesel engines with divided combustion chambers and big cylinder units are suited for continuous operation with rapeseed oil.