BANGOR – Customers of Bangor Hydro Electric Co. may have noticed a slight hike in their electric bills. That’s because the company implemented a 4 percent electric transmission rate increase at the beginning of July.

The increase will affect all Bangor Hydro residential, commercial and industrial customers and would work out to about $3.50 for the average residential customer with a bill of $85.

But company officials say that Bangor Hydro is working hard to keep costs down for consumers and has reduced distribution rates by more than 20 percent over the past seven years.

The money will be used to build new transmission lines to connect to diverse energy sources such as renewable wind, solar, hydro and tidal power, the company said.

“The costs to maintain a reliable transmission system have increased for Bangor Hydro and other New England utilities,” said spokeswoman Susan Faloon. “Reliability standards changed in the summer of 2003 when 50 million customers lost power in the Northeast. These transmission projects will help us continue to meet those standards for all customers.”