Nowadays, the transport sector is one of the main sources of greenhouse gas (GHG) emissions and air pollution in cities. The use of renewable energies is therefore imperative to improve the environmental sustainability of this sector. In this regard, biofuels play an important role as they can be blended directly with fossil fuels and used in traditional vehicles’ engines. Bioethanol is the most used biofuel worldwide and can replace gasoline or form different gasoline-ethanol blends. Additionally, it is an important building block to obtain different high added-value compounds (e.g., acetaldehyde, ethylene, 1,3-butadiene, ethyl acetate). Today, bioethanol is mainly produced from food crops (first-generation (1G) biofuels), and a transition to the production of the so-called advanced ethanol (obtained from lignocellulosic feedstocks, non-food crops, or industrial waste and residue streams) is needed to meet sustainability criteria and to have a better GHG balance. This work gives an overview of the current production, use, and regulation rules of bioethanol as a fuel, as well as the advanced processes and the co-products that can be produced together with bioethanol in a biorefinery context. Special attention is given to the opportunities for making a sustainable transition from bioethanol 1G to advanced bioethanol.

This study characterizes the influence of the El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) on the most important crops in Spain using statistical analysis of the response of historical yields to ENSO and NAO phases. The response to ENSO phases is weak, being only significant for lemon yields, whereas the response to NAO phases is stronger, being significant for lemon, wheat, rye and olive. The results could be useful for producers, allowing them to adjust crop management, and for politicians, allowing better quantification of national crops limits. KEY WORDS: Agriculture · Spain · NAO · ENSOResale or republication not permitted without written consent of the publisher

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The paper assesses the costs of full-scale membrane bioreactors (MBRs). Capital expenditures (CAPEX) and operating expenses (OPEX) of Spanish MBR facilities have been verified and compared to activated sludge plants (CAS) using water reclamation treatment (both conventional and advanced). Spanish MBR facilities require a production of 0.6 to 1.2 kWh per m, while extended aeration (EA) and advanced reclamation treatment require 1.2 kWh per m. The energy represents around 40% of the OPEX in MBRs. In terms of CAPEX, the implementation costs of a CAS facility followed by conventional water reclamation treatment (physical-chemical + sand filtration + disinfection) ranged from 730 to 850 €.md, and from 1,050 to 1,250 €.md in the case of advanced reclamation treatment facilities (membrane filtration) with a capacity of 8,000 to 15,000 md. The MBR cost for similar capacities ranges between 700 and 960 €.md. This study shows that MBRs that have been recently installed represent a cost competitive option for water reuse applications for medium and large capacities (over 10,000 md), with similar OPEX to EA and conventional water reclamation treatment. In terms of CAPEX, MBRs are cheaper than EA, followed by advanced water reclamation treatment.

The present work reviews the role of biogas as advanced biofuel in the renewable energy system, summarizing the main raw materials used for biogas production and the most common technologies for biogas upgrading and delving into emerging biological methanation processes. In addition, it provides a description of current European legislative framework and the potential biomethane business models as well as the main biogas production issues to be addressed to fully deploy these upgrading technologies. Biomethane could be competitive due to negative or zero waste feedstock prices, and competitive to fossil fuels in the transport sector and power generation if upgrading technologies become cheaper and environmentally sustainable.