<Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (August 2017) (Learn how and when to remove this template message) </Td> </Tr> <P> Texans consume the most energy in the nation both in per capita and as a whole . Since 2002, Texas has operated under a mostly deregulated electricity market (however, areas where electricity is provided by either a municipality or a utility cooperative are not always subject to deregulation). </P> <P> The known petroleum deposits of Texas are about 8 billion barrels (1.3 × 10 m), which makes up approximately one - third of the known U.S. supply . Texas has 4.6 billion barrels (730,000,000 m) of proven crude oil reserves . As wells are depleted in the eastern portions of the state, drilling in state has moved westward . </P> <P> Several of the major oil companies have headquarters in Texas, including BP (Houston), ConocoPhillips, Marathon Oil (Houston), Exxon - Mobil (Irving), Tesoro, and Valero (San Antonio). </P>

The economy of the north texas region relies most heavily on the