Last week, an explosion at an Xcel substation in east Denver left tens of thousands of people temporarily without power, including those inside Rose Medical Center.

More problems arose yesterday, as thousands of customers, including the hospital, once again lost power after the temporary replacement site at 13th Avenue and Jackson Street failed (via CBS4).

Xcel Energy spokesman Mark Stutz says the station shut down at 2:53 p.m., after a device that deflects lightning broke down. Power was fully restored about an hour later, when a replacement device was installed, notes The Denver Post.

While the cause of last week’s explosion remains under investigation, it is clear that the repairs will end up costing Xcel customers—probably pennies a month, if approved by regulators, reports 9News.