Electricity has been restored to 14,000 customers in Denver and Lakewood after a nearly three-hour outage Tuesday afternoon, an Xcel Energy spokesman said. Xcel still doesn't know what caused the outage about 11:30 a.m. Tuesday, but power returned about 2:11 p.m., Stutz said. The utility is investigating the cause. The outage impacted customers in an area bounded by Alcott Street to Miller Street and 10th Avenue to Yale Avenue. On a freezing day, the outage could have impacted residents whose homes have electric-powered heating. Stutz said electrical outages can also impact people in natural gas-heated homes who have an electronically controlled furnace.