U.S. nuclear energy facilities generated electricity at a record high level of reliability in 2015, according to preliminary estimates, again demonstrating nuclear energy’s value to consumers, the stability of the electric grid and to the nation’s economy.

Ninety-nine nuclear power plants operating in 30 states posted an estimated average capacity factor of 91.9 percent, based on preliminary 2015 data compiled by the Nuclear Energy Institute. That surpasses the industry’s prior record set in 2007 by one-tenth of a percentage point. Capacity factor measures the total electricity generated as a percentage of potential generation for the entire year.

The amount of electricity generated in 2015 exceeded the amount produced in 2014, even though one less plant operated due to the 2014 closing of Vermont Yankee. This record efficiency is even more important as states strive to meet new carbon-reduction targets for the electric sector.

“The 2015 data confirm yet again what a tremendous asset nuclear energy technology is,” said NEI Chief Nuclear Officer Anthony Pietrangelo. “U.S. nuclear power plants continue to operate at exceptional levels of safety and reliability, while generating affordable electricity that consumers and our economy rely on. This is due to the hard work and dedication of the highly skilled men and women who work at these facilities and the reactor vendors and suppliers who provide support services.”