This paper analyses the economical viability of replacing fossil energy by renewable sources by taking CO>sub>2>/sub> emission legislation into account. A single chemical industry case, formic acid production, is studied in a tangible manner to provide a concrete example for industrial managers and legislators. The practical case was supported by examining scientific and other databases. This study indicates that new environmental legislation makes it economically viable to replace fossil energy by renewable sources, such as wood biomass. However, the results indicate that the current and coming legislation do not cover the entire product life cycle of carbon dioxide releasing chemical products. The results of this paper can be utilised by managers of companies with high-energy consumption and/or high usage of fossil raw materials.