Various technologies to reduce emissions from the transportation sector have emerged in the past decades, including biofuels and electric vehicles. Electrification is vital to decarbonization, but it is insufficient alone and may not apply to all transportation sectors. There is considerable interest in biofuels to complement electrification in decarbonizing transportation. In this study, we evaluate the extent to which biomass can contribute to the decarbonization of the transportation sector as electrification of the light-duty fleet increases. Using two biomass availability scenarios established at two different price points (≤$40 per dry ton and ≤$60 per dry ton), the study examines how electrification and biomass resources can be used to meet near-term societal transportation needs when biomass use is prioritized towards different transportation sectors. We consider the transportation sector as a whole, including the light-duty, heavy-duty, marine, and aviation sectors. The results show that biofuels could fulfill about 27% of energy demand across the heavy-duty, aviation, and marine sector at ≤$40 per dry ton and more than 50% at ≤$60 per dry ton by 2050, while electrification could be the primary means of decarbonizing light-duty vehicles. While in 2050 transportation-related greenhouse gas emissions could be 26% lower than in the baseline case with extensive electrification of the light-duty sector, this percentage could be increased to 37% and 52% at ≤$40 per dry ton and ≤$60 per dry ton, respectively, with increased market penetration of biofuels in the other transportation sectors.

This work presents a mathematical model for the simultaneous optimisation of water and energy usage in hydraulic fracturing using a continuous time scheduling formulation. The recycling/reuse of fracturing water is achieved through the purification of flowback wastewater using thermally driven membrane distillation (MD). A detailed design model for this technology is incorporated within the water network superstructure in order to allow for the simultaneous optimisation of water, operation, capital cost, and energy used. The study also examines the feasibility of utilising the co-produced gas that is traditionally flared as a potential source of energy for MD. The application of the model results in a 22.42% reduction in freshwater consumption and 23.24% savings in the total cost of freshwater. The membrane thermal energy consumption is in the order of 244 × 10³ kJ/m³ of water, which is found to be less than the range of thermal consumption values reported for membrane distillation in the literature. Although the obtained results are not generally applicable to all shale gas plays, the proposed framework and supporting models aid in understanding the potential impact of using scheduling and optimisation techniques to address flowback wastewater management.

Achieving the United States' target of net-zero greenhouse gas emissions by 2050 will require technological transformations and energy sector migration.

Renewable MCCI bio-blendstocks with advantageous properties co-optimized with engines and a ducted fuel injection could reduce engine-out emissions leading to reduced total cost of vehicle ownership and a potential to penetrate the market at scale.