This thesis focuses on multistage stochastic programming for CO2 emissions management models. It defines the multistage stochastic programming in general, portfolio selection problem with utility function but also with other new approaches such as using risk measures, chance constraint or second order stochastic dominance. For testing this models we need to also reformulate our problems to fit scenario tree which are generated. For some models we also need to reduce the dimension of scenario tree. Thus some techniques for scenario tree dimensionality reduction are discussed. We try to apply all these approaches to our data and get results on real data from power energy sector. For this sector, the decisions about allowances might be very important as they are not granted any allowances.

El sector de pasta i paper és considerat un dels set sectors industrials més intensius en consum energètic. La producció i consum d'electricitat i de vapor esdevenen les fonts majoritàries d'emissions de gasos d'efecte hivernacle en aquest sector industrial. Les fàbriques papereres poden assolir objectius de reducció d'emissions mitjançant reducció en origen (substitució de combustibles, introducció d'energies renovables) o bé a partir de mesures d'eficiència energètica en el propi procés. En aquest context, s'ha desenvolupat un mètode de distribució d'emissions que permet assignar a cada unitat d'operació del procés paperer, el seu grau de responsabilitat en emissions. També s'han avaluat diferents mètodes de càlcul de factors d'emissió de vapor i electricitat, tant per plantes de cogeneració com per sistemes individuals. A partir d'aquesta avaluació s'han proposat nous mètodes alternatius als analitzats. Aquests mètodes i els factors d'emissions s'han aplicat a dues fàbriques papereres catalanes. / Pulp and paper sector is considered one of the seven industrial sectors with a higher energy intensive profile. Power and steam production and consumption are the main responsible for green house gas emissions of this industrial activity. Paper industries can achieve reductive emission targets by considering emissions origin (replacing fuels, aplying renewable energies) as well as improving energy efficiency of the process itself. An emission allocation tool has been developed with the purpose of approaching to each unit operation of the papermaking process its related emissions share. In addition, energy-emission factors regarding power and steam generation in combined heat and power plants and in single heat and power systems have been evaluated. Some new methods for calculating different emission factors have been proposed after the analysis. Two Catalan paper mills have been used as case-studies to apply, both allocation method and emission factors.