National Energy Regulator of South Africa (NERSA) was the regulatory authority that presided over the electricity supply industry (ESI) in South Africa. In November 2005, the National Energy Regulator of South Africa (NERSA) replaced the NER. NERSA is responsible for regulating the price of pipeline gas and petroleum, reducing monopoly in the energy sector, improving competition and boosting economic growth. NERSA, established in terms of the National Energy Regulator Act of 2004, is mandated to regulate South Africa's electricity, piped gas and petroleum industries and to collect levies from people holding title to gas and petroleum. The idea behind a single regulator for the three industries was to improve efficiency and cut costs. It is also expected to boost private sector participation in the energy sector. As an economic regulator, NERSA will ensure a level playing field and prevent abuse by monopolies. While legislation exists to govern the gas and petroleum pipeline industries, they were previously not subject to control by a regulatory body. The regulator is important as it will encourage greater access and competition in a sector dominated by single major players: Eskom in electricity, Petronet in petroleum and Sasol in gas. NERSA's functions include issuing licences, setting and approving tariffs and charges, mediating disputes, gathering information pertaining to gas and petroleum pipelines, and promoting the optimal use of gas resources.