The treatment of flue gases from fossil fuel fired power stations by tri-reforming with natural gas or by coal gasification could become an attractive approach for converting the Co-2, H2O, O-2, and N-2 contained in these flue gases via syngas processing into useful products, such as methanol, hydrogen, ammonia, or urea. The present study determines the constraints for achieving such thermochemical reactions under conditions of thermoneutrality, by reacting the flue gases with water, air, and natural gas or coal at 1000-1200 K. The implications of such reactions are examined in terms of CO2 emission avoidance, fuel saving, economic viability, and exergy efficiency. (c) 2006 Elsevier B.V. All rights reserved.