CO 2 emission and oil use reduction through black liquor gasification and energy efficiency in pulp and paper industry

Abstract

We examine consequences of new energy technologies in the pulp and paper industry with respect to net CO 2 emissions and oil use. The entire production chain from the extraction of primary resources is included in the analysis. Stand-alone production of electricity and transportation fuel from biomass is included to balance the systems compared, so that they produce the same CO 2 emission and oil use reductions. The technologies considered are black liquor gasification (BLG) with electricity and motor fuels production in chemical pulp mills and increased energy efficiency in thermomechanical pulp mills. The technologies are evaluated with respect to net CO 2 emission, oil use, primary energy use, biomass use and monetary cost. We find that BLG in chemical pulp mills is favourable compared to stand-alone production of fuels and electricity from biomass. It is more efficient to implement BLG with motor fuels production and stand-alone electricity production from biomass, than to implement BLG with electricity production and stand-alone production of motor fuels. Increased energy efficiency in refining of thermomechanical pulp gives CO 2 savings more efficiently than stand-alone production of electricity from biomass. Sensitivity analysis indicates that our conclusions are robust with respect to energy and biomass prices and the choice of coal or natural gas for marginal electricity. Newsprint from thermomechanical pulp would require slightly less biomass and have lower costs than paper from chemical pulp, per metric ton (t) product, when the systems are also required to render the same oil use and CO 2 emission reductions. Substituting mineral fillers for 25% of the chemical pulp changes the balance in favour of the chemical pulp paper. At an oil price of 40 US$/barrel, all studied pulp and paper mill technology improvements give unchanged or reduced monetary costs also when oil use and CO 2 emissions are not balanced with stand-alone bioenergy plants.