Even though consumers were enjoying low rates, demand kept increasing. A 1962 long-range plan commissioned by the utility estimated that Muscatine Water and Light would need to make additional improvements in transmission lines, substations, and distribution equipment during the 1960s at an estimated cost of more than $2 million. 

Two things were driving the increase in demand during the 1960s. Summer electric peaks, in particular, continued to grow during the 1950s and 1960s, driven in part by the growth of home and business air conditioning. The second reason for the rapid increase in electric power demand in the 1960s had to do with the continuing economic diversification in Muscatine. What had been a sleepy river town in the years before World War II, dreaming of its once vibrant pearl button industry, had become an industrial dynamo by the mid-1960s. 

In 1964, for the first time in its history, the utility reported half of its operating revenues came from the primary power category–in essence, sales to industrial electric customers. Typical of the industrial resurgence in Muscatine was the rapid growth of HON Industries. Started in an abandoned pearl button factory as the Home-O-Nize Corporation at the end of World War II, HON originally started designing and making kitchen cabinets. By the late 1960s, the firm had become one of the primary manufacturers of steel office furniture in the United States. Other new and expanding major industrial customers included Grain Processing Corporation and its subsidiaries, Kent Feeds Inc. and Americana Seeds Inc., Bandag Inc., Monsanto, Heinz USA/StarKist, and Prime Mover. 

By mid-decade, it was becoming obvious that the 1962 10-year study had underestimated the growth in electric power demand. In 1967, the board of trustees approved the construction of what would become known as Unit 8. 

The new 66,000-kilowatt (kW) turbo-generator doubled capacity of the Muscatine plant for the sixth time in the utility’s history, and from the time that the first contracts were signed until Unit 8 went online in December 1969, little more than three years elapsed. 

By the time the new plant went online, the utility also had a new name. It was changed to Muscatine Power and Water (MPW) in 1967. 

The power plant expansion was accompanied by a real strengthening of MPW’s transmission system. Included in the plans was construction of a 161,000-volt (V) transmission line to connect with Iowa-Illinois Gas and Electric Company at Kilpeck Landing. The utility also increased its power interchange capability with its old neighbor, the Eastern Iowa Light and Power Cooperative.