Biomass is the only renewable organic resource available in great abundance. If exploited to its fullest extent, it has the capacity to completely replace fossil fuels for energy generation, simultaneously maintaining a clean environment, free from the greenhouse gases. Technologies for the production of the third — and fourth- generation biofuels are likely to have a very great impact on reducing the problem of global warming caused by the GHGs and in taking us from an era of carbon neutral environment to a carbon-negative environment. These include biofuels produced by upgraded pyrolysis and gasification technologies and solar-to-fuel technologies. The concept of biorefineries has already made the biomass conver­sion technology a great attraction among industry investors because biorefineries have the potential of reaping great profits by generating costly fuels as the main product, and in addition to this, costlier value-added products such as chemicals, as by-products, the original cost of the initial raw material being almost negligible. The future biorefineries would use efficient feedstock upgrading processes, where the raw materials are continuously upgraded and refined. Fractionating the biomass into its core constituents before using it as feedstock will give the much lacking uniformity in the biomass, making the processing in a biorefinery all the more efficient. Only the residue remaining after all the useful components are converted, should be used for generation of heat and electricity. This will ensure complete usage of the biomass. The catalytic cracking/upgrading technologies used in the thermochemical conversion methods are likely to improve with the use of nano­particle-based catalysts. Simultaneously, the development of biocatalysts will enable biomass conversions under milder conditions, and with greater efficiencies, leading to more environment friendly ‘‘green’’ processes. Bioethanol and biodiesel are the two biofuels that have the potential of replacing gasoline. The rapid advances and the unlimited scope of the biochemical conversion technologies and the algal conversion processes are likely to make this a reality in the near future. Genetic manipulation of microorganisms to improve production of efficient cel — lulases and hemicellulases will go a long way in improving yields and reducing conversion times in the biochemical conversion of lignocellulosic biomass. Recombinant DNA technology is being applied to bacteria and fungi in order to achieve this. Strains of microorganisms which have the ability to co-ferment different types of substrates simultaneously, will improve the economy and effi­ciency of the biochemical conversion processes. On the other hand, transgenically modified plants can be grown which will have a reduced lignin content and an upregulated cellulose biosynthesis. ‘‘Plant factories’’ can be set up, where such genetically modified plants can be grown which have the capacity to capture and store more carbon so that the overall energy density of the biomass increases. The bright future of biomass conversion into energy is clearly evident from the large number of integrated biorefineries which have already come up in different parts of the world.