PAETEC co-founder Arunas Chesonis, who left the company when the Windstream purchase was completed, has a new job in a new field, but among old friends.

Renewable energy firm Sweetwater Energy Inc.  led by another PAETEC co-founder, Jack Baron said on Friday it has named Chesonis as its CEO. Chesonis had been serving as Sweetwater’s chairman of the board. Sweetwater Energy turns sugars into water-based solutions from non-food plant materials. The company then sells the solution to refineries, which turn it into biofuels, biochemicals and bioplastics.

Sugar is the new oil,” Chesonis said in a prepared statement. “Most of the products, including plastics and biochemicals that have been traditionally made from petroleum, are increasingly being made from sugar, a sustainable and renewable resource that we can economically manage. Ive been working with companies and universities across the renewable energy spectrum in the last several years to develop new technologies that are ready for prime time, and its extremely gratifying to join such a promising young company right here in Rochester.”

Baron started Sweetwater Energy in 2008; he left as head of PAETC’s energy division to do that. Baron will become president and COO of Sweetwater Energy when Chesonis joins  the company did not specify a date.

Arunas and I have long talked about how the renewable energy sector is a new frontier where large-scale monopolies like big oil companies are facing brand new competition from companies like Sweetwater Energy,” said Baron. “In many ways, the industry is much like telecom back when we founded PAETEC.”

PAETEC was founded in 1998, during the boom of the CLEC years. The service provider survived the telecom bust of the early 2000s, going on to thrive through multiple acquisitions and a diversified strategy  equipment and software divisions, as well as energy, for example. Chesonis was a key figure during those years at industry conferences and smaller, partner-focused events. This past August, PAETEC shocked the competitive telecom industry by agreeing to sell to Windstream, which has been moving away from its rural residential roots into the lucrative business market.