Electricity losses

Losses of electricity through the delivery system are significant. The U.S. Energy Information Administration (EIA) estimates that losses through the delivery system are 65%. Another way of saying this is that nearly two-thirds of the primary energy used to create electricity is lost before the electricity arrives at the customer meter.

Source: Graphic from Enerdynamics’ Energy Industry Overview course developed using data from the Energy Information Administration (EIA)

The majority of losses are due to primary energy that is lost as waste heat. Here is where losses occur:

Generation

It is estimated that of the 65% of primary energy lost, 59% of it is lost in the generation process. This includes:

• Waste heat occurring due to inefficiencies in the process of converting primary energy to electricity. This makes up about 54% of the primary energy lost.

• Electricity used internally by the power plant during operations. This makes up about 5% of the primary energy lost.

Transmission and distribution grid

Another 5 to 7% of the original primary energy is lost during the delivery of electricity through the T&D system. The energy becomes waste heat released in the air due to line losses and conversion losses in transformers and other line equipment. 

After the electricity arrives at the consumer premises, there are additional losses due to line loss within the building and inefficiency in converting the energy to useful services (heat, light, electronic processing, etc.). While amounts wasted within a consumer’s premises vary widely depending on the type of consumer and the type of equipment being used, the chart below show typical losses in buildings and factories:

End use	Estimate energy loss
Industrial boilers	20%
Industrial process heat	15%
Pumps and fans	40%
Motors	5-10%
Incandescent light bulb	90%
LED light bulb	10%

Energy efficiency is the practice of reducing losses through investment in technology that is more efficient. Many in the industry believe that losses can be significantly reduced by investing in energy efficiency technologies that are already available today. Further improvements are likely to come through research in improving energy generation and energy-consuming equipment.