SPP, as it is known in Croatia, or CNG in English, is natural gas in a gaseous state compressed at a pressure of up to 220 bar at 15ºC that is used for the propulsion of motor vehicles as an alternative fuel. This significantly reduces the volume required for gas storage and allows for mobile use, that is, use to power motor vehicles.

According to the regulations drafted by the Government of Croatia, compressed natural gas is the fuel that offers the best compromise between environmental characteristics, availability of energy resources and technological development. Due to the simple chemical composition, exhaust gas emissions are lower compared to other fuels. SPP is much more environmentally friendly than other fossil fuels and guarantees much cleaner combustion, and its advantages in vehicles are manifested in lower maintenance costs, longer engine life and significant fuel price savings. .

Every CNG vehicle in Croatia has two tanks, one for CNG and one for gasoline. The autonomy of the vehicle depends on the size of both tanks and is generally equal to or greater than the autonomy of a gasoline car. The energy value of one kilogram of CNG is equal to 1.57 liters of gasoline, 1.39 liters of diesel and 1.98 liters of autogas. CNG vehicles are developed and manufactured in the factory and are therefore reliable. The vehicles are similar to gasoline vehicles, so the scope of maintenance is similar. In addition, gas facilities for CNG vehicles must be maintained.

Croatia is one of the countries poised to become a major producer of natural gas. The Molve field has been producing excellent results for decades, and more and more significant quantities are being obtained from Ivana, a gas field in the Adriatic. In addition, according to the studies carried out, Croatia, in the Podravina and Adriatic areas, has huge gas reserves, so the price of CNG in Croatia can remain cheap for many years.