<P> A similar situation exists in gas transport, where compressor stations along pipelines use energy to keep the gas moving, or where gas liquefaction / cooling / regasification in the liquiefied natural gas supply chain uses a substantial amount of energy, even though the scale of the loss is not as pronounced as it is in electricity . </P> <P> Distributed generation and distributed storage are means of reducing total and transmission losses . </P> <Table> <Tr> <Th> Source </Th> <Th> 2012 production (TWh) </Th> <Th> Percentage of Total </Th> </Tr> <Tr> <Td> Coal </Td> <Td> 1,709 </Td> <Td> 41.5% </Td> </Tr> <Tr> <Td> Petroleum </Td> <Td> 30 </Td> <Td> 0.7% </Td> </Tr> <Tr> <Td> Natural Gas </Td> <Td> 1,066 </Td> <Td> 25.8% </Td> </Tr> <Tr> <Td> Nuclear </Td> <Td> 813 </Td> <Td> 19.7% </Td> </Tr> <Tr> <Td> Renewable sources </Td> <Td> 486 </Td> <Td> 11.8% </Td> </Tr> <Tr> <Td> Other </Td> <Td> 21 </Td> <Td> 0.5% </Td> </Tr> <Tr> <Td> Total </Td> <Td> 4,120 </Td> <Td> 100% </Td> </Tr> </Table> <Tr> <Th> Source </Th> <Th> 2012 production (TWh) </Th> <Th> Percentage of Total </Th> </Tr>

The energy needs of the united states in the 1990s have