Owners of economical diesel cars are both winners and losers in the current energy crisis. Your cars consume less than petrol engines, especially on the motorway, but the fuel also costs significantly more – currently between 2.20 and 2.30 euros per liter. Freight forwarding companies and building contractors in particular are currently groaning under massively increased costs that are being passed on directly to consumers.

Vegetable oil instead of diesel – good idea?

Depending on the area of ​​application, electric vehicles are an alternativebut for many people the only option is to drive less or at least save as much fuel as possible. As always during periods of high fuel prices, many people go to the supermarket and stock up on vegetable oil. Canisters of rapeseed oil are available in some wholesale markets for as little as 1.99 euros per liter. But can you really pour vegetable oil into the tank to save money given the current horror prices at the pump? Even the corruption of “heating oil Ferrari” for fast diesel cars shows that the good old diesel engine is tough. Or rather, tough wasbecause things look a little different with modern diesel engines.

FOCUS online spoke to one of Germany’s leading experts on diesel engines, Professor Thomas Koch from KIT Karlsruhe. Koch clearly advises against its use: “Salad oil is certainly suitable as an energy source to drive an internal combustion engine as a fuel replacement. However, salad oil does not meet the specifications of the EN590 fuel standard. In old diesel vehicles from the 1980s or 1990s, which still used mechanical injection without exhaust gas aftertreatment, salad oil works quite problem-free. In modern diesel engines with an exhaust gas aftertreatment such as the oxidation catalytic converter, typically in the However, when combined with a particle filter, it acts like a catalyst poison,” says Koch.

An old diesel Benz swallows everything

The ADAC is also critical of the use of vegetable oil; this is only possible in old vehicles: “Their engines function with much lower injection pressures. In addition, these often do not have sensitive sensors that can immediately detect differences in running behavior when using the wrong fuel. This is why older diesel engines with distributor injection pumps run on vegetable oils, at least temporarily. However, the service life of these engines is also limited in the long term,” say the ADAC technology experts.

HVO diesel – good for the engine, but unfortunately not cheaper

As an alternative to normal diesel you can use HVO 100 diesel made from residual materials. “If you want to do something good for the environment with a demonstrably audited CO2 reduction potential of around 90 percent, then filling up with HVO fuel is very effective,” recommends engine expert Thomas Koch. Long-term users of the fuel also report fewer problems with emissions testing and smoother running.

However, the price of this fuel is still linked to normal diesel, so there is currently no price advantage at the pump. Only in the first few weeks of the current energy crisis was it possible to fill up with HVO cheaper because the fuel was handled more slowly than with normal diesel and some gas station chains passed on the price advantage to their customers.

“As soon as vegetable oil is designated for use as fuel, the energy tax arises and the user becomes the tax debtor, says the main customs office. Taxation occurs when it ends up in the tank as a diesel substitute, while refined rapeseed oil as a product is only subject to seven percent VAT,” continues “Agrarheute”. However, technical conversion is absolutely necessary for the engine to operate smoothly.