The absolute level of prices of motor fuels and their trends of development have a strong influence on the total consumption of fuels and demand for various fuels. The increase of prices of motor fuels should encourage a reduction in the use of such fuels for the final consumers, which would also reduce the impact on the environment. Relative changes of prices of energy products, which are mutual substitutes, influence the change in fuels.
In general, the prices of energy products have realistically increased with regard to 1995. The main reason is high oil prices on international markets.
In Slovenia, oil derivatives are the most expensive energy product, primarily due to a relatively high share of taxes in their final price. Slovenia is also one of the few EU countries which entirely regulates the price of oil derivatives. The state prescribed a methodology for the basic pricing of fuels, while also influencing the final price by the level of excise duty. The basic purpose of the introduction of the regulation of oil derivatives prices was the protection of consumers against oligopolistic pricing by oil dealers and the possibility of implementing protective measures against the influence of global oil prices on inflation in Slovenia.
Since 1995, the prices of oil derivatives have realistically increased with an average annual growth level above 4.5 %; however, the main reason for the increase in prices before and after the year 2000 is not the same. In the first period, the growth of prices was primarily a result of the higher taxation of oil derivatives (the introduction of excise duty and VAT), while the main reason for the growth of retail prices of oil derivatives in recent years was primarily the growth of the basic price of fuels due to high oil prices on world markets.
The increasing trends of prices in the period 1995-2000 for gasoline and diesel are quite similar. In 2002, a lower price for diesel fuel can be noticed, which is primarily a result of lower basic prices of diesel fuel and lower excise duties, which does not apply anymore for 2005. The change of real prices for diesel fuel in the period 2005–2008 amounts to 21.5 %, and for gasoline to 21.3 %. The growth dynamics for autogas are significantly smaller than for other motor fuels; a slight increase in the final price was indicated in 2008. The change in real prices in the period 2005–2008 for autogas amounts to 12.0 %, and for the period 2007–2008 to 12.2 %. Due to lower prices and a smaller impact on the environment, autogas presents one of the most widespread alternatives to classic oil fuels.
In the area of oil derivatives, the prices of premium unleaded gasoline (NMB 95) and diesel fuel (D2) in 2008 were around 15 % below the average prices of EU-15 countries. Two main reasons are the lower basic price of fuels and largely the fuel taxation level, which remains significantly below the level of the most developed countries.
Slovenian energy policy, defined in the Resolution on the National Energy Programme, does not set any specific objectives with regard to energy prices; however, it stipulates mechanisms in the area of the competitiveness of energy supply, the implementation of which will have an indirect impact on higher competitiveness and energy prices. The opening of markets is significant for the provision of a competitive energy supply, primarily to industrial consumers, for the higher efficiency of operations of energy companies, higher transparency of energy supply and energy markets and better provision of energy services to consumers. Energy policy does not have a direct influence on the basic energy price; the price for the use of networks is also determined by the Energy Agency of the Republic of Slovenia. The only mechanism, by which the state influences the final energy price, is the implementation of fiscal policy, through which it determines the energy taxation level.