In November 2007 Piet Schenkelaars finalised a study on the opportunities for pulp and paper manufacturers to produce and sell biofuels to external customers. The study was commissioned by Pira International Ltd. (UK). In essence, it focusses on how replacement of conventional (Thomlinson) recovery boilers by black liquor gasification (BLG) systems could be beneficial to pulp and paper manufacturers, both in economic as well as environmental terms.