UPDATE (10 p.m. Sunday): Power is starting to return to certain parts of Portland.
The AEP-Texas power outage map shows more than 2,200 customers currently are without power in Portland.
According to the AEP-Texas spokesman Omar Lopez, the estimated restoration time is 11:30 p.m. for about 2,100 customers.
The remaining 100 are expected to have power restored at about 1:30 a.m. Monday.
Lopez said crews are still assessing and don't yet have an exact cause for the outage.
This is a developing story. Check back with KRIS 6 News for updates.