Generally speaking most utilities, grid operators and regulators don't really worry too much about transmission and distribution line losses. After all, the costs are generally passed on to the consumer or "socialized." Surprisingly, utilities are often considered the largest single consumer of electricity as T&D losses range from about 6% (in Japan) to nearly 24% (in India). The ACCC conductor, generally used to increase the capacity of existing transmission and distribution lines to accommodate load growth or very high emergency loads, is also being used to reduce line losses by 25 to 40% or more depending upon load level.

 

This is due to the very low electrical resistance of the fully annealed type 1350-O aluminum used in most ACCC conductor designs, as well as the fact that most ACCC designs also use compact trapezoidal-shaped strands, which enables the incorporation of up to 28% more aluminum with no weight or diameter penalty, as the composite core is much lighter than steel. 

 

While every transmission engineer recognizes that line losses increase exponentially with current (think I^2R), the ACCC conductor, while rated for emergency operation up to 200 degrees C (~390 F), actually runs substantially cooler and more efficiently compared to other conductors of the same diameter and weight under any load condition.  The chart below was created from data compiled by Hydro One wherein a number of Drake size conductors were placed on a 65 meter (215 foot) test span and a current of 1,600 amps was applied.  You can see not only that the ACCC conductor exhibited the least amount of thermal sag (upper blue line), it also ran 60 to 80 degrees C (140 to 176 F) cooler than the other conductors under the same load.  This represents a huge reduction in line losses.

 

Considering that generation capacity is wasted supporting those losses, reducing losses can not only reduce fuel consumption and associated emissions, it can also 'free up' generation capacity that can now be deployed to 'paying customers.' Whether or not your organization considers line losses when they evaluate the never ending list of upcoming projects, at the end of the day, investment in efficiency does pay dividends.   To see this for yourself, request a free copy of CTC Global's CCP software program discussed in the sidebar below.  To better understand how utilities are beginning to identify and assess the true value of investment in transmission, please also check out the group known as WIRES.  There is a link to their website directly below.  Take a look at the Brattle report "The Benefits of Electric Transmission: Identifying and Analyzing the Value of Investments." It is available on the WIRES website.