A centralized server managed by an employer receives reports of renewable energy generation from many remote generation sites belonging to its employees, and then summarizes and details the generation for certification by a certifying standards process. Renewable energy power generation monitors are placed at independent remote locations owned by the employees that collectively report to the server any fractional units of renewable energy power generation represented in aggregate by particular REC's traded on the e-trading platform. And, an ad-hoc sellers consortium automatically aggregates fractional and small units of REC's into marketable lots according to individual preferences of participating small sellers, and the marketable lots of REC's are offered for sale on the e-trading platform.