Electrical losses on the transmission and distribution system can be categorized into two type – Technical losses and Non-Technical Losses.
Technical losses are caused by resistance of the power lines, transformer and regulator windings, corona loss in extra and ultra high voltage transmission system, dielectric losses in underground cables, poor power factor, drop in voltage and overloaded equipment.
Non-Technical losses arise due to theft (stealing energy, meter tampering, illegal connection), meter malfunction, unpaid bills, and bill invoice issues
The U.S. Energy Information Administration (EIA) estimates that total electricity transmission and distribution losses average about 6% of the electricity that is transmitted and distributed annually in the United States. Energy theft in the US equate to $6 billion in annual losses which costs utilities 1%-3% of their revenue.
Worldbank data map below shows transmission and distribution losses as a % of output
The chart below shows Transmission and distribution losses in selected countries in 2009 (in million U.S. dollars). This statistic represents transmission and distribution losses of global smart grid drivers in selected G20 nations in 2009. That year, the non-technical losses in Brazil amounted to about 5.1 billion U.S. dollars.
Another map showing losses for 12 countries from carboncounter.wordpress.com
In 2010, electricity losses in India during transmission and distribution were about 24%, while losses because of consumer theft or billing deficiencies added another 10–15%.
So what can we do to reduce losses?
To reduce losses we have to improve power quality, power factor, install appropriately sized equipment taking into consideration future load growth, deploy sensors to monitor transmission and distribution grid performance (distribution automation), use software analytics tools to mine smart meter data to identify theft accurately and inform law enforcement, make smart meters tamper proof or program alerts in case of tampering.