The indicator Energy tax shows the level of taxation of individual energy products. Electricity tax is indicated in EUR per kilowatt hour (EUR/kWh), natural gas tax in EUR per gigajoul (EUR/GJ), and liquid fuel tax in EUR per litre of fuel (EUR/l).

Electricity and natural gas taxes show the level of taxation for typical consumer groups for industrial and household consumers; however, the tax for industrial consumers does not consider the value-added tax (VAT).

In the majority of countries, the basic purpose of energy taxation is of a fiscal nature, since energy taxes represent primarily a source of funds inside the national budget. However, the role of energy tax is not only of a budgetary nature. Energy taxation represents a good method of internalising external costs. By implementing energy taxation, the state influences the final level of energy prices, through which it can also directly and indirectly influence energy consumption. With higher energy taxation, the state also encourages final users to reduce their energy consumption, which again reduces the impact on the environment. On the other hand, through energy taxation the state interferes with the price relations, which also influences the replacement of environmentally-harmful fuels with fuels that are less harmful to the environment.

The current practice of shaping taxes in the area of energy indicates that energy tax is determined by the state with its fiscal policy, whereby the state energy policy plays only a side role in the shaping of taxes. Energy taxes are currently the only mechanism, available to the state, through which the state can influence the final price of individual energy products.

The green tax reform, which would encourage sustainable behaviour by producers and consumers, is one of the possible answers to the challenges of environmental pollution due to incorrect market signals. The purpose of the green tax reform is to solve the described problem by redistributing the tax burden from work tax to environment tax (on the use of energy or other resources and raw materials, environmentally dangerous substances and products) and reforming the policy of incentives (for instance, the suspension of environmentally dangerous incentives). A key characteristic of the green tax reform is that the introduction of new environmental taxes does not lead to a general increase in taxation, but that the tax burden is only redistributed. Although in Slovenia we have a developed system of environmental taxation, a comprehensive green tax reform would contribute to better energy efficiency.

In general, energy tax has increased in real terms since 1995; the only exception is the electricity tax for industrial consumers, where the direct taxation decreased due to the introduction of VAT. The biggest taxation changes appeared for natural gas for household consumers, where the taxes increased in real terms by almost 800 % (it is necessary to consider the relatively small level of taxation in 1995), and for heating oil, where the taxes increased in real terms by almost 350 %.

Households
In Slovenia, approximately the same taxes were in force for electricity for households in the period 1992–2000. In 1999 VAT was introduced, due to which the taxation level in households increased by half. In 2006, VAT was the only electricity tax paid by households; however, in 2007 an excise duty on electricity was also introduced. The price for 2007 is the basic price for the first half of this year, including the excise duty, which amounts to 0 €. In the price for 2008, the excise duty is already considered and amounts to 0.002€ 1995. For natural gas in the period from 1995–2000, a moderate growth of taxes is typical, which is also the main reason for the significant increase in natural gas prices in this period. After 2000, the natural gas tax increased primarily for household consumers, mainly due to the introduction of the tax on CO₂ and excise duties; the introduction of VAT was not such a significant factor (see Figure 5). The share of taxes in the final price of electricity in 2008 amounted to 20.6 %, which is more than in 2000 and 1995 when the share of taxes represented 16 % or 9.1 % of the final price. The main reason for such an increase was the introduction of VAT and an increase in the VAT level from 19 % to 20 % (1 January 2002).

Industry
With the introduction of VAT in industry, tax is no longer considered a direct tax burden, which means that after its introduction electricity for industrial consumers was not subject to tax; in 2008, the impact of excise duty could already be noticed. Taxes on natural gas in industry increased in the period 2000–2008 primarily due to the introduction of excise duties and higher taxes on CO₂ (see Figure 5). In general, the share of taxes in the final price in industry is lower than in households. The share of taxes in the final price of natural gas amounted in 2008 to 6.5 %, which is more than in 1995 when this share was 4.8 % and slightly less than the share of taxes in 2000.

Oil derivatives
A relatively high level of taxes was typical for oil derivatives in the period 1995–2000. After the introduction of VAT in 1999, a period of moderate growth followed, with the exception of UMG 95 fuel where the taxes increased until 2002. In the period 1995–2000, the real growth of final prices of oil derivatives is mainly a result of higher taxes (introduction of excise duty and VAT); taxes after 2000 do not significantly influence the growth of final prices. The share of taxes in the final price of energy was in 2008, with regard to 1995, higher for UMG 95 fuel and heating oil; however, in comparison with 2000 it decreased as a result of a significant increase in basic prices, while the taxes did not significantly increase. The main reason for such a high share of taxes in the final price of oil derivatives was the introduction of the environmental tax on CO₂ emissions (for heating oil), excise duty and VAT.

In general, energy tax in Slovenia is lower than the average tax in the EU-15, including the electricity tax in 2008 for industrial and household consumers. Electricity for industrial consumers in the first half of 2007 was not subject to tax; on the other hand, the average taxation in the EU-15 was 10.9 €/MWh. Electricity tax for household consumers in the EU-15 amounted to 37.6 €/MWh, and in Slovenia to 17.1 €/MWh.

Natural gas tax for industry in the EU-15 amounted on average in 2007 to 0.57 €/GJ, which represents a 28 % lower tax rate than in Slovenia. Natural gas tax for households in the EU-15 in 2007 amounted to 3.49 €/GJ, which is 12 % more than in Slovenia (3.11 €/GJ) (see Figure 7, Figure 8, Figure 9).

In Slovenia, the share of taxes on final energy is smaller than the share of taxes in the EU-15; the only exception is the tax on natural gas for industrial consumers (see Figure 6).

In comparison with the EA-15, tax on motor fuel in 2008 was by 30 % lower for UMG gasoline and 20 % lower for diesel fuel. A comparison with the neighbouring countries shows that taxes on motor fuel in 2008 in Austria, Italy and Hungary were higher than in Slovenia (see Figure 9).