Jesse Hall and hundreds of other buildings around Columbia went black last week, but only for an hour.

March 29 marked Columbia’s sixth year participating in the annual Earth Hour movement, where businesses, organizations and residents of voluntarily turn off their lights from 8:30 to 9:30 p.m. to raise awareness on energy use.

During this year’s hour, Columbia dropped 2.1 megawatts, or 1 percent, of its electrical load, according to a city news release. Last year’s drop was 2 megawatts.

To calculate the Earth Hour drop, the city compared Earth Hour electric usage to average of Saturday electrical usage during the designated hour.

“We look at what the community electricity averages and then at Earth Hour,” Columbia sustainability manager Barbara Buffaloe said.

Buffaloe said the department knows that sometimes the drop in electricity usage is unintentional since it falls during a time when some people go to bed or have turned off their lights to leave their house. However, data from two city substations showed that the decrease in electric load came from residential areas and was higher-than-average.

“We looked at measurements of each substation,” Columbia Water and Light spokeswoman Connie Kacprowicz said. “Substations break up usage of power more than Columbia’s power as a whole.”

The biggest drop came from the substation in the northwest section of Columbia, which includes the Columbia Mall. The next-biggest drop came from the residential area located in the southeast section of Columbia.

While most businesses aren’t open that late on Saturdays, Sycamore Restaurant and Eleven Eleven in downtown Columbia decided to participate by replacing their main dining lights with candlelight, Buffaloe said.

“Industry and commercial businesses use a lot of energy in the community, but (voluntarily turning off lights) is similar to voting with your switch,” Buffaloe said. “Every little bit counts.”

Buffaloe said there are ways to decrease the electrical load that go behind Earth Hour. She suggested residents work to improve energy efficiencies in their own homes, take fewer car trips, use public transportation, walk or ride bikes and support local food production or have a garden. The goal is to decrease greenhouse gas emissions as much as possible.

“Earth Hour is a symbolic gesture to get people aware of the need to save energy,” Kacprowicz said.

Buffaloe calls electric usage sustainability outside of Earth Hour “going beyond the hour.”

Columbia was one of thousands of cities that participated in the worldwide event this year. The World Wildlife Fund started the event in Australia in 2007. Since the event’s inception, more than 100 countries have participated in Earth Hour.