Thermodynamic, economic and environmental assessment of energy systems including the use of gas from manure fermentation in the context of the Spanish potential

One of the prospective technologies that can be used for energy generation in distributed systems is based on biogas production, usually involving fermentation of various types of biomass and waste. This article aims to bring novelty on the analysis of this type of systems, joining together thermodynamic, economic and environmental aspects for a cross-cutting evaluation of the proposed solutions. The analysis is made for Spain, for which such a solution is very promising due to availability of the feedstock. A detailed simulation model of the proposed system in two different cases was built in Aspen Plus software and Visual Basic for Applications. Case 1 involves production of biogas in manure fermentation process, its upgrading (cleaning and removal of CO2 from the gas) and injection to the grid. Case 2 assumes combustion of the biogas in gas engine to produce electricity and heat that can be used locally and/or sold to the grid. Thermodynamic assessment of these two cases was made to determine the most important parameters and evaluation indices. The results served as input values for the economic analysis and environmental evaluation through Life Cycle Assessment of the energy systems. The results show that the analysed technologies have potential to produce high-value products based on low-quality biomass. Economic evaluation determined the break-even price of biomethane (Case 1) and electricity (Case 2), which for the nominal assumptions reach the values of 16.77 €/GJ and 28.92 €/GJ, respectively. In terms of environmental assessment the system with the use of biogas in gas engine presents around three times better environmental profile than Case 1 in the two categories evaluated, i.e., carbon and energy footprint.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 799439. Dr. Martín-Gamboa states that thanks are due to FCT/MCTES for the financial support to CESAM (UID/AMB/50017/2019), through national funds

Revisiting the role of steam methane reforming with CO2 capture and storage for long-term hydrogen production

Road transport is associated with high greenhouse gas emissions due to its current dependence on fossil fuels. In this regard, the implementation of alternative fuels such as hydrogen is expected to play a key role in decarbonising the transport system. Nevertheless, attention should be paid to the suitability of hydrogen production pathways as low-carbon solutions. In this work, an energy systems optimisation model for the prospective assessment of a national hydrogen production mix was upgraded in order to unveil the potential role of grey hydrogen from steam methane reforming (SMR) and blue hydrogen from SMR with CO2 capture and storage (CCS) in satisfying the hydrogen demanded by fuel cell electric vehicles in Spain from 2020 to 2050. This was done by including CCS retrofit of SMR plants in the energy systems model, as a potential strategy within the scope of the European Hydrogen Strategy. Considering three hypothetical years for banning hydrogen from fossil-based plants without CCS (2030, 2035, and 2040), it was found that SMR could satisfy the whole demand for hydrogen for road transport in the short term (2020–2030), while being substituted by water electrolysis in the medium-to-long term (2030–2050). Furthermore, this trend was found to be associated with an appropriate prospective behaviour in terms of carbon footprint.This research has been partly supported by the Spanish Ministry of Economy, Industry and Competitiveness (ENE2015-74607-JIN AEI/FEDER/UE)

Prospective techno-economic and environmental assessment of a national hydrogen production mix for road transport

Fuel cell electric vehicles arise as an alternative to conventional vehicles in the road transport sector. They could contribute to decarbonising the transport system because they have no direct CO2 emissions during the use phase. In fact, the life-cycle environmental performance of hydrogen as a transportation fuel focuses on its production. In this sense, through the case study of Spain, this article prospectively assesses the techno-economic and environmental performance of a national hydrogen production mix by following a methodological framework based on energy systems modelling enriched with endogenous carbon footprint indicators. Taking into account the need for a hydrogen economy based on clean options, alternative scenarios characterised by carbon footprint restrictions with respect to a fossil-based scenario dominated by steam methane reforming are evaluated. In these scenarios, the steam reforming of natural gas still arises as the key hydrogen production technology in the short term, whereas water electrolysis is the main technology in the medium and long term. Furthermore, in scenarios with very restrictive carbon footprint limits, biomass gasification also appears as a key hydrogen production technology in the long term. In the alternative scenarios assessed, the functional substitution of hydrogen for conventional fossil fuels in the road transport sector could lead to high greenhouse gas emission savings, ranging from 36 to 58 Mt CO2 eq in 2050. Overall, these findings and the model structure and characterisation developed for the assessment of hydrogen energy scenarios are expected to be relevant not only to the specific case study of Spain but also to analysts and decision-makers in a large number of countries facing similar concerns.This research has been partly supported by the Spanish Ministry ofEconomy, Industry and Competitiveness (ENE2015-74607-JIN AEI/FEDER/UE

Influence of stratification, heat and removal of teguments on breaking of seed dormancy in almond

En: XIII GREMPA Meeting on almonds and pistachios = XIIIème Réunion du GREMPA sur l'amandier et le pistachier . Zaragoza : CIHEAM-IAMZ, 2005. Eds: Oliveira M.M., Cordeiro V.-- Meeting of the Mediterranean Research Group for Almond and Pistachio, 2003/06/01-05, Mirandela (Portugal).-- 5 pages, 2 figures.[EN] The effect of stratification, heat, and endocarp and tegument removal on the breaking of seed dormancy was studied in 3 almond cultivars. In the first assay, the nuts with endocarp were stratified at 7 degrees C for 15 weeks. In the second, the nuts with endocarp were stratified at 7 degrees C for 4 weeks. Then, non-germinated seeds were kept at 22 degrees C for 7 weeks more to promote germination. Then, the remaining non-germinated nuts were cracked and the tegument was removed. The percentage of germinated seeds of each cultivar was recorded weekly in both assays. The results showed a different effect of each treatment on seed germination for each cultivar, related to their flowering time. The removal of the endocarp and the tegument in seeds that had not fulfilled their chilling requirements, produced the same effect as stratification and, finally, similar percentages of seed germination were observed in comparison with the first treatment.[FR] "Influence de la stratification, de la chaleur, et de l'élimination des téguments sur la rupture de dormance des semis d'amandier". Au cours de ce travail nous avons étudié l'effet de la stratification, de la chaleur, et de l'élimination de l'endocarpe et du tégument dans la rupture de la dormance de 3 variétés ('Desmayo Largueta', 'Del Cid' et 'Wawona') d'amandier [P. dulcis (Mill.) D.A. Webb] avec des dates de floraison distinctes. Dans le premier traitement, les semis avec endocarpe ont été stratifiés pendant 15 semaines à 7ºC. Dans le second traitement, les semis avec endocarpe ont été stratifiés à 7ºC pendant 4 semaines. Les semis qui n'ont pas germé ont été exposés à 22ºC pendant 7 semaines et après cette exposition l'endocarpe et le tégument ont été supprimés des semis qui n'ont pas germé. Chaque semaine le pourcentage de germination des semis a été calculé. Les résultats ont mis en évidence une relation entre les besoins de stratification des semis et la date de floraison de chaque variété. Le traitement à la chaleur ne peut pas induire la germination des semis qui n´ont pas satisfait leurs besoins en froid. L'élimination de l'endocarpe et du tégument produit une augmentation de la germination similaire à l´effet de la stratification de telle façon que les pourcentages finaux de germination sont similaires dans les deux traitements.This work has been financed by the project “Mejora genética del almendro” (AGL2001-1054-C03- 01) from the Spanish Ministry of Science and Technology.Peer reviewe

Early selection of late-flowering almonds

En: XIII GREMPA Meeting on almonds and pistachios = XIIIème Réunion du GREMPA sur l'amandier et le pistachier . Zaragoza : CIHEAM-IAMZ, 2005. Eds: Oliveira M.M., Cordeiro V.-- Meeting of the Mediterranean Research Group for Almond and Pistachio, 2003/06/01-05, Mirandela (Portugal).-- 6 pages, 4 tables.[EN] The correlations between seed germination or leafing time and flowering time in almond [P. dulcis (Mill.) D.A. Webb] were studied in a population of 502 seedlings from 13 families. The aim of the study was to discover the possibilities of an early selection of those seedlings with late flowering in relation to germination of seeds or leafing time in the following year. The crosses were conducted in 1997. The seeds obtained were germinated by conventional stratification at 7°C, and the number of weeks necessary for the germination of each seed recorded. The trees were planted in 1998. Between 1999 and 2002 their leafing time was recorded, and in 2001 and 2002 also their flowering time. The results indicated that these characteristics bear a relation when considering the population globally, but with a high variability. However, within each family, the correlations between these characteristics were not important and, in most cases, not significant. In the case of germinationflowering, the lack of correlation seems to be the consequence of the germination depending mainly on the female parent. In the case of leafing-flowering, the lack of correlation was due to the positive or negative correspondence between leafing and flowering and to the genotype x environment interaction. In our opinion, to obtain seedlings with an extra-late flowering time, the selection of parents with very late flowering time is essential, with subsequent selection of the seedlings during their first flowering. An early selection regarding the leafing period could be applied with a certain degree of success when, for any reason, interested in selecting late-flowering trees coming from parents with very late and very early-flowering periods. In such cases, the high variability expected could compensate, to a certain degree, for the differences between leafing and flowering.[FR] "Sélection précoce d'amandiers à floraison tardive". Les corrélations entre la germination de la graine ou la date de débourrement et la date de floraison chez l'amandier [P. dulcis (Mill.) D.A. Webb] furent étudiées dans une population de 502 plantes issues de 13 familles. L'objectif de l'étude était de découvrir les possibilités d'une sélection précoce de ces plantes ayant une floraison tardive en relation avec la germination des graines ou la date de débourrement dans l'année suivante. Les croisements furent réalisés en 1997. Les graines obtenues ont germé selon une stratification conventionnelle à 7°C, et le nombre de semaines nécessaires à la germination de chaque graine est enregistré. Les arbres furent plantés en 1998, et leur date de débourrement enregistrée entre 1999 et 2002, ainsi que leur date de floraison en 2001 et 2002. Les résultats indiquèrent que les caractéristiques ont mis en évidence une relation si l'on considère la globalité de la population, mais avec une forte variabilité. Cependant, dans chaque famille, les corrélations entre ces caractéristiques se sont avérées peu importantes et dans de nombreux cas, non signifiantes. Dans le cas de la germination-floraison, la faible corrélation semble être la conséquence du fait que la germination soit contrôlée principalement par le parent femelle. Dans le cas du débourrement-floraison, la faible corrélation serait due à une asynchronie positive ou négative entre le débourrement et la floraison, et aussi à l'interaction entre le génotype et l'environnement. Selon nous, afin d'obtenir des sélections aux dates de floraison très tardives, la sélection de parents avec une date de floraison très tardive est essentielle, avec la sélection de plantes pendant leur première floraison. Une sélection précoce prenant en compte la période de débourrement pourrait être appliquée avec un certain taux de réussite quand, quelle que soit la raison, nous voulons obtenir des sélections très tardives à partir d'un croisement entre un géniteur très précoce et un autre très tardif. Dans ce cas, la grande variabilité attendue pourrait compenser, à un certain degré, des différences entre le débourrement et la floraison.This work has been financed by the project AGL2001-1054-C03-01 ("Mejora Genética del Almendro") from the Spanish Ministry of Science and Technology. The authors also acknowledge the support of the Spanish Ministry of Science and Technology for the contract of Dr. P. Martínez-Gómez.Peer reviewe

Breaking seed dormancy in almond (Prunus dulcis (Mill.) D.A. Webb)

8 pages, 4 tables.-- Available Online 17 Sep. 2003.Seed dormancy affects germination and subsequent seedling growth in many plant species. In this work the effect of temperature (cold and heat treatments), flowering time of genotypes, and hardness of endocarp on the break of seed dormancy in four almond cultivars, including a broad range of flowering dates, was studied. Mature seeds, with and without endocarp, were stratified at 7 °C for 1–10 weeks, followed by 5 weeks at 22 °C. The number of germinated seeds were recorded weekly for each cultivar, and cold and heat treatments. Despite the great variability observed within cultivars, a relationship between chilling requirements of cultivars for flowering and stratification requirements of seeds for germination was observed. With endocarp, stratification time required to overcome seed dormancy ranged between 6 (early flowering cultivars Desmayo Largueta and Ramillete) and 8 weeks (late-flowering cultivars Mono and Wawona) on average. Elimination of the endocarp reduced the period of stratification needed for germination in hard-shelled cultivars by 3 weeks. This effect was less important in soft-shelled almonds. No important differences between cultivars were observed for heat requirements. Two weeks at 22 °C was enough to reach the higher germination percentage after each cold treatment.This work has been financed with the project “Mejora Genética del Almendro” (AGL2001-1054-C03-01) from the “Plan Nacional de I+D” of Spanish Ministry of Science and Technology.Peer reviewe

Pollinizer influence on almond seed dormancy

9 pages, 3 tables.-- Available online 17 Nov. 2004.Breaking seed dormancy is necessary for the completion of germination. Maternal tissues (integument and endocarp) appear to control seed germination, although the effect of the pollinizer has also been described. In this work, the influence of the pollinizer flowering time was studied on the stratification requirements of almond seed germination. Stratification requirements were determined in seeds (with and without endocarp) from crosses between a female progenitor and pollinizers of different flowering dates. The results showed an influence of the pollinizer in the stratification requirements of seeds with endocarp. However, no correlations were found between pollinizer flowering date and stratification requirements, which seem to be determined mainly by the female progenitor. In the case of seed stratification without endocarp, the results did not show any influence of pollinizer on stratification requirements. The observed variability within females (within or between crosses) could be due to differences in the shell characteristics, the different accumulation of inhibitors in the integument, or the genetic nature of the embryos.The work has been financed by the project AGL2001-1054-C03-01 entitled ‘‘Mejora Genética del Almendro’’ from the Spanish Ministry of Science and Technology. The authors also acknowledge the support of the Spanish Ministry of Science and Technology for the contract of Dr. P. Martínez-Gómez.Peer reviewe