Malaysia's energy infrastructure sector is largely dominated by Tenaga Nasional, the largest electric utility company in Southeast Asia, with over RM99.03 billion of assets. Customers are connected to electricity through the National Grid, with more than 420 transmission substations in the Peninsular linked together by approximately 11,000 km of transmission lines operating at 66, 132, 275, and 500 kilovolts. The other two electric utility companies in the country are Sarawak Energy and Sabah Electricity. In 2013, Malaysia's total power generation capacity was over 29,728 megawatts. Total electricity generation was 140,985.01 GWh and total electricity consumption was 116,087.51 GWh. Energy production in Malaysia is largely based on oil and natural gas, owing to Malaysia's oil reserves and natural gas reserves, which is the fourth largest in Asia-Pacific region.