Comprehensive energy product supply on the way to a low carbon society is a strategic goal of Petrol Group. We trade in oil, natural gas, heat, electricity and alternative fuels. We introduce alternative fuels proactively.
The largest sales segment are the petroleum products. In 2018, we sold 3.5 million tonnes of petroleum products, which is 4 percent more than in 2017. Of this, 50% of sales were generated in Slovenia, 28% in EU markets and 22% in SE Europe.
The Transport Renewable Energy Regulation mandates fuel market operators to gradually replace petroleum fuels with appropriate alternative fuels. These are fuels that are partly or wholly obtained from renewable sources and are more environmentally friendly in terms of emissions. In the years 2017-2018, Petrol fulfilled its obligation almost exclusively by mixing biofuels with fossil fuels.
The RES Regulation prescribed a biofuel share of 6.2% for 2017 and 7% for 2018. In 2017, Petrol achieved approximately one percent (in terms of energy) of biofuels and 3.2 percent in 2018. The major part was achieved by adding biodiesel to diesel fuel, and to a lesser extent, gasoline with bioethanol (in the form of BioETBE) were also marketed.
Liquid petroleum gas (LPG) is one of the highest quality and cleanest fossil fuels. LPG sales are becoming an increasingly important business within the Petrol Group, as regional infrastructure is being established, which is the basis for presence in the wider SE European region. Petrol Group is active in the areas of LPG supply and construction and management of LPG distribution networks. We sold 157.6 thousand tonnes of LPG in 2018, which is 4 percent more than in 2017. In Slovenia we manage 6 concessions for the supply of LPG.
Natural Gas is a very suitable energy source for providing a reliable energy supply and a low carbon energy system. After the incorporation of Geoplin d.o.o. Petrol Group has a market share of approximately 53% in the natural gas retail field in Slovenia. Natural gas consumption has been increasing slightly over the last three years, with an increasing number of users. In 2018, Petrol Group sold 19.9 TWh of natural gas.
Demand for electricity is growing. Petrol Group has a market share of around 10% in the retail electricity market in Slovenia. We delivered electricity to more than 54,000 household customers in 2018. For the supply of electricity to business customers, the offer is segmented and adjusted with a focus on customer needs. In 2018, Petrol Group sold 20.3 TWh of electricity, of which 1.2 TWh to end customers.
In 2018, we offered Eles the opportunity to purchase the electricity needed to perform tertiary frequency control, thereby helping to ensure the safe, reliable and efficient operation of the transmission system.
An important segment of Petrol's comprehensive energy supply is heat supply for heating, which is carried out through common boiler rooms, district heating systems and cogeneration systems. At the end of 2018, we operated 29 district heating systems, 19 of which are public utilities, seven are proprietary systems and three are commercial activities as classified by the Energy Act. In 2018, 106,020 MWh of heat was sold to customers with a total power of 121,449 kW from all systems.