Improved efficiencies can be realized all along the energy chain, from the conversion of primary energy (oil, for example) to energy carriers (such as electricity) and finally to useful energy (the heat in your toaster).

• 效率的提升可以实现在整条能源供应链上，从初级能源（例如原油）的转换，到能源输送（例如电力），以及最后的能源使用（例如家用烤面包机）。