North America's biggest 100-percent biomass plant is a former coal plant under conversion about a two-hour drive west from Thunder Bay, Ontario. The facility burned its last load of coal and powered down one year ago, but it's all abuzz with activity now. I got an up-close look at the upgrades in-progress as part of a tour of renewable energy companies, groups, and facilities sponsored by the Ontario Ministry of Economic Development, Trade and Employment (MEDTE).