What’s the cost of power grid line losses -- and what’s to be done about them?

Utilities have long accepted that the laws of physics dictate a certain amount of power lost as heat as it’s transmitted from generator to end-user. California lost about 6.8 percent of its power to line losses in 2008, at a value of about $2.4 billion in electricity.

Losses of 7 percent or so are the norm today in the United States, a rule that holds across Europe as well. Japan has gotten line losses down to 5.1 percent through a $100 billion transmission buildout in the 1990s, but it’s an exception. Utilities in developing nations can see losses in the double-digit percentage range.

That’s a lot of power lost, and it has a corresponding value in carbon. To be precise, the 1.4 trillion kilowatt-hours lost out of 20 trillion used around the world each year represent about 1.2 trillion metric tons of carbon dioxide emissions. Cutting it by a third would add up to 53 gigawatts of power plants that wouldn’t need to be built, or 290 million metric tons of CO2 not put into the atmosphere, according to CTC Global.

Plenty of technology is on hand to help out. On the transmission side, high-voltage direct current transmission lines like those being built at a record-shattering pace in China are promising significant efficiency improvements over their AC cousins. Superconducting high-voltage cables can theoretically get that line loss down to zero (with a bit of conversion loss), but they’re too expensive for all but the most congested, high-priced power hotspots.

For already existing transmission grids, synchrophasors are providing real-time measurement of power quality, which allows grid operators to do things like run transmission lines at higher capacity when they’re sure it’s safe to do so, or see congestion ahead of time to reroute around it. We've got smart grid contenders including Cisco, Alstom and S&C Electric Co. working on the synchrophasor front, which includes a lot of hardcore data crunching along with grid sensors and communications.

On the distribution grid level, we’re seeing conservation voltage reduction (CVR) or volt/VAR optimization (VVO) deployments that lower overall voltage across the grid, both for overall efficiency and to shed load during peak demand times. That can push 4 percent to 6 percent efficiency gains, and save enough power to avoid building new power plants -- a key to meeting emissions targets. ABB (and Ventyx), Schneider Electric (and Telvent), General Electric, S&C Electric Co., Utilidata and others are all working on this distribution-side efficiency.