Converting the Százhalombatta refinery is costly and time-consuming. According to the minister, funding was requested from the EU for this project, but was not received.

When asked whether the separation problem could be solved using our own resources, he replied that this would require an investment of tens or hundreds of billions of forints. The decision must be made by Mol, as they own the refinery. State support is also an option. The extent of this support will depend on EU regulations.

At the end of March 2022, Mol issued a statement saying that "the Danube Refinery (in Százhalombatta) was designed primarily to process Russian blended crude oil (REB): currently, it can use other types of crude oil at a maximum rate of 35%". In Hungary, Tamás Pletser, an oil and gas market analyst at Erste Bank, and Attila Holoda, a former deputy state secretary for energy, have both stated that switching from Russian oil to other types of oil would not cause any problems. Several foreign analysts also told business daily Napi.hu that they did not understand why this issue was being raised, as no costly investments are necessary because crude oil refining is an ongoing process.

Compared to other chemical processes, crude oil refining is not particularly complex, and the basic principle is essentially the same in every refinery worldwide. The main differences lie in desulfurisation and the removal of other impurities. The process typically involves filtration and mixing, followed by hydrogenation. In essence, industrial hydrogenation desulfurisation processes allow gas to enter the storage tank, where hydrogen and sulphur (as well as several other substances) form bonds. This allows the resulting hydrogen sulphide gas or sulphuric acid to be filtered out.

After desulfurisation, the mixture is separated into groups with almost identical numbers of carbon atoms, using a distillation process similar to that used for distilling brandy. In fractional distillation, the crude oil is heated to above 350°C, at which point it mostly becomes gaseous. This vapour is then gradually cooled in the fractionating column. The distillate with the lowest boiling point range settles at the top of the column, while the distillate with the highest boiling point range settles at the bottom.

This principle is used by refineries around the world, including those in Százhalombatta, Bratislava, and Rijeka. Two processes that require more complex optimisation in the plants are hydrogenation and carbon number separation, which are used for different types of oil.

However, according to experts interviewed by Napi.hu,

the time taken for calibration should not exceed six months for any of these operations, depending on the age of the equipment.

This is true even if new mixers are required. Fractionation columns require minimal investment and materials.

Another source claimed that refineries could be converted much more quickly than Mol had officially acknowledged.

While the Hungarian oil industry group has optimised itself for current conditions, this is fundamentally a business preference rather than a technological one. The source told economx.hu in May 2022 that what the Százhalombatta oil refinery can produce does not depend on whether Ural oil is imported or what type of oil is fed into the Adria pipeline at Omisalj in Croatia.