Texas both produces and consumes more energy than any state in the U.S. It controls one-quarter of U.S. proven oil reserves. Energy companies looking to grow or to establish a U.S. presence set up operations in Texas. The primary electricity transmission system in Texas is independent of the rest of the country (a long-time source of pride). The Electric Reliability Company of Texas, or ERCOT, is responsible for regulating the generation and supply of power to 85% of the state, except the extreme eastern and western portions.