The solar panels, installed and operated by SunEdison, now generate about 3 percent of the brewery's electricity needs.
Last year the brewery also constructed a bio-energy recovery system, which provides more than 15 percent of the brewery's fuel needs by turning nutrients in brewing wastewater into renewable biogas used to decrease the use of natural gas.
Other conservation and efficiency improvements at the Fairfield brewery include a project to recover steam to heat water in the brewhouse, and replacing brewery lighting with energy-efficient fixtures on timers, according to the brewery.
The improvements have helped the brewery decrease fuel use by 38 percent, water use by 32 percent, and electricity use by 14 percent since 2004.
"Our increased use of alternative energy sources is the latest example of how we strive to be the best beer company in a better world," Kevin Finger, general manager of the Anheuser-Busch Fairfield brewery, said in a prepared statement.