Investigating the environmental sustainability of a seabass and seabream aquaculture system in Portugal based on life cycle and nexus approaches

Aquaculture plays an essential role in supplying animal-source food and protein worldwide, in this way contributing to several sustainable development goals. Notwithstanding this, the aquaculture sector's long-term environmental sustainability is a major concern due to overall environmental impacts. To date, and to the best of the authors' knowledge, assessments of aquaculture systems in Portugal from an environmental perspective, and the nexus between resource consumption and nutrition issues, are still lacking. This study bridges this gap by analysing an aquaculture system in Portugal in a comprehensive manner by applying and combining life cycle assessment and resources-protein nexus approaches. The overall results highlight feed as the main factor responsible for the total impact in all impact categories selected, ranging from 74 % to 98 %. Climate change impact results in 2.88 kg CO2-eq per kg of medium-size fish (functional unit). The resources-protein nexus shows that 504.1 MJex is needed to obtain 1 kg of edible protein, with a high dependency on non-renewable resources (59 %), mainly oil by-product fuels used in feed production. After identifying environmental hotspots, potential strategies to be adopted such as resource consumption reduction, eco-certification and ecosystem-based management are suggested, in this way ensuring long-term aquaculture production and environmental sustainability.publishe

Accounting for GHG net reservoir emissions of hydropower in Ecuador

Hydropower is one of most important considered renewable technologies to provide electricity generation worldwide. Bearing in mind the lack of LCA studies and the development of several hydroelectric projects in Ecuador, the purpose of this paper is to present a complete environmental performance of two hydropower schemes (dam and run-of-river) located in this country, through the life cycle assessment combined with reservoir GHG emissions approach. The run-of-river scheme had better environmental performance than the dam scheme. Very high emissions were found, being 547 Kg CO2-eq/MWh for dam scheme, which most of those emissions were originated in the reservoir, while the run-of-river scheme only score 2.6 Kg CO2-eq/MWh. However, comparing with fossil fuel power plants, hydropower dam case still has lower emissions in its entire life cycle. The paper remark that the majority of LCA studies which focus on dam hydropower scheme only consider the emissions of the construction, putting aside the loss of the ecosystem and the emissions caused by the impoundment. Moreover, the analysis also included the impact associated to water uses since reservoirs are usually devoted to several purposes (flood lamination, irrigation, ecological flow, power generation)

Metodología para la determinación del desempeño ambiental neto de la generación hidroeléctrica

El desarrollo social y económico humano ha alcanzado tales niveles que la energía se ha convertido en un elemento indispensable del vivir diario. Desde la Revolución Industrial, la demanda y consumo energético de las sociedades en el mundo no ha dejado de aumentar, sobre todo de fuentes no renovables de energía. Dada la dependencia en recursos finitos, su contaminación e impacto en el clima global, el mundo mira hacia las energías renovables como alternativa, en la búsqueda de la sostenibilidad, a la par de que se procura mitigar el cambio climático y estabilizar el clima a futuro. En este marco, las energías renovables juegan un rol de vital importancia, siendo que sus tecnologías de aprovechamiento son vistas como parte importante de la solución. Entre esas fuentes, la energía proveniente del agua resalta, debido a sus grandes potenciales en el mundo, su madurez tecnológica y su alta eficiencia. Gracias a su temprano desarrollo tecnológico, la energía hidráulica ha liderado desde siempre las energías renovables. Aunque aprovechan recursos conceptualizados como ilimitados e inagotables, todas las tecnologías de aprovechamiento de fuentes renovables de energía están limitadas y condicionadas ya sea por la disponibilidad, eficacia y eficiencia en el aprovechamiento del recurso como por los impactos de diferentes índoles que éstas generan. En el marco ambiental-ecológico, el estado de arte evidencia y expone importantes avances en el análisis y evaluaciones en centrales hidroeléctricas. Sin embargo, el estado de arte también evidencia un vacío de conocimiento, ya que se desconoce cual es el desempeño neto ambiental de la generación hidroeléctrica, a pesar de la existencia de múltiples evaluaciones. En consecuencia, este trabajo tiene como objetivo principal proponer una metodología para la determinación del desempeño ambiental neto de la generación hidroeléctrica. Para ello, se consideraron como casos de estudios dos centrales hidroeléctricas, una de regulación con interposición (embalse), de 42 MW, y otra de agua fluyente con desviación, de 21 MW, localizadas en Ecuador. Con la finalidad de establecer la metodología, se consideraron dos evaluaciones: al análisis del ciclo de vida y la evaluación ecológica, ésta última a partir de los servicios de los ecosistemas. Con primer punto, se llevó a cabo el análisis del ciclo de vida en base a la norma ISO 14040. Ante el problema del cambio climático, se profundizó en las emisiones de gases de efecto invernadero a través de un balance, a fin de conocer las emisiones netas de cada central hidroeléctrica. En particular, existen suficientes evidencias que confirman que los embalses hidroeléctricos son emisores principalmente de dióxido de carbono y sobre todo, de metano. En este marco, se determinó un procedimiento para estimar y proyectar las emisiones de dióxido de carbono y metano del embalse, a lo largo de la vida útil de la central hidroeléctrica en cuestión, lo que contribuyó en la realización del balance de emisiones. Por otra parte, dado el uso y consumo de recurso hídrico, dentro de este apartado también se analizó la huella hídrica de las centrales hidroeléctricas así como también el nexo agua-carbono. Como segundo punto, en el Capítulo IV de este trabajo se realizó la evaluación ecológica a partir de los servicios ecosistémicos, para lo cual se realizó una extensa revisión bibliográfica. En este contexto, se propuso un balance ecosistémico por medio de la valoración económica de los servicios ecosistémicos. Esta valoración se realizó aplicando los métodos correspondientes. De esta forma, la valoración en conjunto con el balance ecosistémico permitió valorar el desempeño de la energía hidráulica desde un enfoque diferente al análisis del ciclo de vida. Dadas las particularidades de la central hidroeléctrica con embalse, su diseño fue modificado con la finalidad de comparar con el caso original y tener una mayor compresión de la relación hidroenergía-ecosistemas. A ello se suma un análisis y determinación del coste ecológico de generación de dicha fuente de energía, basado en los resultados del balance ecosistémico señalado. Como parte central y objetivo de este trabajo, se llevó a cabo la integración y balance del análisis del ciclo de vida y la evaluación ecológica a fin de conocer es desempeño ambiental neto de la generación hidroeléctrica en un único resultado. Para ello, primero se hizo una revisión bibliográfica general sobre la integración de evaluaciones. A partir de esto, se establecieron dos posibles alternativas con sus respectivos procedimientos para la integración. Tras analizar factores y elementos inherentes a la integración tales como la doble contabilidad, las unidades, la biodiversidad, alcance de las evaluaciones, etc., se escogió y aplicó el procedimiento que mejor se ajustaba a la integración, dando lugar a un resultado único expresado en unidades monetarias. Por último, en el Capítulo VI se realizó un análisis y valoración de sostenibilidad de ambos casos hidroeléctricos en función de los múltiples indicadores obtenidos a partir de la aplicación de las evaluaciones y de la integración, los cuales se correlacionaron con los beneficios teóricos socioeconómicos determinados para cada proyecto. Como parte final de este capítulo, se expusieron lineamientos para las nuevas y futuras políticas hidroenergéticas, basadas en los resultados obtenidos. En síntesis, se concluye que la metodología propuesta permite abarcar todos los aspectos necesarios para determinar el desempeño neto ambiental hidroeléctrico. En este marco, el aprovechamiento de la energía hidráulica, a través de centrales hidroeléctricas, genera impactos importantes negativos ambientales-ecológicos, que en términos económicos, supera significativamente el coste de generación. De acuerdo a los resultados, la central hidroeléctrica de agua fluyente con desviación tiene un desempeño ambiental neto de -0,08 $/kWh mientras que la central de regulación con interposición (embalse) -0,96$/kWh, indicando claramente que la primera es más sostenible. En particular, la central con embalse no es efectiva en la mitigación contra el cambio climático, ya que a partir de transformación del ecosistema terrestre, elimina área de capacidad de absorción de carbono, creando a su vez una nueva fuente para la emisión de gases de efecto invernadero. A ello se agrega que este esquema hidroeléctrico genera grandes pérdidas ecosistémicas con efectos importantes sobre la biodiversidad. Por lo tanto, de manera general no debe asumirse que las tecnologías de aprovechamiento de fuentes renovables de energía son sostenibles per se. A pesar de un mejor desempeño, la implementación de futuras centrales de agua fluyente con desviación deberá ser evaluada en base a múltiples indicadores biofísicos, en el marco de la sostenibilidad fuerte, con la finalidad de aprovechar esta fuente renovable de energía de manera más equilibrada. Finalmente, es necesario que las políticas hidroenergéticas estén orientadas hacia una ecología política, para así conservar y recuperar el patrimonio natural. <br /

Assessing a bio-energy system with carbon capture and storage (BECCS) through dynamic life cycle assessment and land-water-energy nexus

Nowadays, much attention is being paid to so-called Negative Emissions Technologies (NETs), designed to remove carbon dioxide from the atmosphere and keep global temperature rise below 1.5 °C. The deployment of NETs can trigger environmental impacts, which can be addressed through the lens of Life Cycle Assessment (LCA). According to the literature, there are several drawbacks when NETs are assessed under the life cycle framework. In this sense, this study aims at contributing to the literature by assessing a NET in a manner that the existing drawbacks are overcome. For such purpose, dynamic LCA and land-water-energy nexus were applied to a Bioenergy with Carbon Capture and Storage system (BECCS). The results show that harnessing residual forest biomass for electricity generation and carbon storage accomplished a great positive climate performance. In line with European climate goals, climate change impact resulted in −2.49E+04 kg CO2eq/MWhe and −3.40E+04 kg CO2eq/t Cstored at year 20. However, the BECCS system analyzed comes at the expense of impacting land, water and energy that cannot be overlooked. The land impact was 3.57E+05Pt/t Cstored and 2.61 E+05Pt/MWhe, green water impact was 11.1 m3/t Cstored and 8.16 m3/MWhe, and the Energy Return on Energy Investment (EROI) was 3.34. The sensitive analysis indicates that special attention should be paid to the efficiency of the system since it directly impacts on land, water and energy (EROI). Finally, this study contributes to increasing the knowledge on NETs, thus supporting climate-energy policymaking

Environmental and energy performance of residual forest biomass for electricity generation: gasification vs. combustion

Bioenergy systems have a great potential worldwide to substitute fossil fuels mainly because they may contribute to greenhouse gas emissions reduction. In Portugal, several biomass combustion-based power plants have been built in the last decade. Biomass gasification is a potential alternative to combustion but its environmental impacts should be evaluated. The goal of this study is to assess and compare the environmental and energy performance of direct gasification and combustion (both in fluidized bed) using residual forest biomass (RFB) from eucalypt in Portugal. In order to achieve the goal, life cycle assessment was applied, complemented with the Energy-Returned-On-Energy-Invested (EROI) indicator. The boundaries of the systems comprise three stages: (1) forest management, (2) collection, processing and transportation, and (3) electricity generation. The results indicate that gasification performs environmentally better than combustion in 5 out of 8 impact categories addressed. Conversely, combustion has greater EROI than gasification. After running a sensitivity analysis where the efficiency of the gasifier was changed from 53% in the base scenario to 57%, it is shown that the environmental performance of gasification improved in the range of 2–8%. The study concludes that gasification may be a good alternative to current combustion systems in Portugal.publishe

Dependence on the socio-economic system impairs the sustainability of pasture-based animal agriculture

Livestock systems contribution to environmental change is controversial. Pasture-based systems are considered a sustainable alternative due to their adaptation to the use of local natural resources. However, they have limited productivity per product unit and, in Europe, depend on public economic support. Furthermore, they are heterogeneous in farm structure and resources use, which may determine their sustainability. We use emergy accounting to assess the sustainability of mountain pasture-based cattle systems and analyse the variability among farms. Emergy accounting assesses the sustainability performance of complex systems (i.e., farming systems) and their interaction with other systems (i.e., the environment and the socio-economic system) focusing on the origin, quality and quantity of the energy required for the system to function. Results show that pasture-based systems largely use local natural renewable resources but depend largely on the wider socio-economic system given their reliance on public economic support and purchased animal feeds. This economic dependence turns out in most farms largely using non-renewable resources. Increasing self-produced feeds and grazing on natural pastures can reduce the dependence on the socio-economic system and improve farm sustainability.La investigación que ha conducido a estos resultados ha recibido financiación del programa de investigación e innovación Horizonte 2020 de la Unión Europea -GenTORE- en virtud del acuerdo de subvención n.º 727213, y del Gobierno de Aragón en virtud de la subvención Fondos Agrupados de Investigación (A14_17R). E. Muñoz-Ulecia tiene un contrato predoctoral del Gobierno de Aragón.Publishe

Hydropower policy in Ecuador: an analysis from environmental perspective and recommendations for future policymaking

Renewable energies are vital to tackle climate change and reduce environmental issues. In this sense, hydropower plays a key role. Broadly speaking, hydropower is perceived as a climate ally and considered environmentally sustainable. However, its development is still controversial due to the well-known environmental and ecological impacts that put its environmental sustainability in question. In this sense, this study aims to analyse and discuss hydropower development and policy in Ecuador from an environmental perspective. The analysis addresses the research question of to what extent the business-as-usual hydropower policy is compatible and consistent with national environmental sustainability and Buen Vivir (Good Living) goals. For such purpose, the analysis is conducted by applying a proposed conceptual framework composed of critical elements such as Buen Vivir principles, rights of nature and the evidence on the environmental sustainability of hydropower. The analysis highlights the main environmental drawbacks of the BAU-HP policy and finds that the current development and policy of hydropower is ultimately detrimental to achieving national environmental sustainability and Buen Vivir. Moreover, it easily infringes the Rights of Nature and conflicts with the conservation of ecosystems and biodiversity. Following the findings, several environmental sustainability-oriented recommendations are suggested for future hydropower policymaking

Rigid Versus Variable Energy Sources in Water-Pressurized Systems: An Economic and Environmental Analysis

[EN] The layouts of most urban water systems are known. A head tank with an appropriate elevation is used to supply water through the network at a pressure equal (or higher) to that set by the relevant standards. Furthermore, equalization, fire and emergency storage are important benefits of tank use, as is the possibility of avoiding peak rate electricity fares. However, at the end of the last century, some tanks were reported to have a negative impact the quality of water, and recommendations were made to limit their volume and revise their geometry. Recently, alternative options have been considered. Equalization can be achieved with pumps with variable-frequency drivers, emergency situations can be avoided with electric oil generators and solar plants can be used to offset other generation types and reduce energy costs. Therefore, this article analyses the performance of tanks as an energy source, and tank and pump supply methods are directly compared; overall, direct supply through pumps is cheaper, more energy efficient and more environmentally convenient. Therefore, in the context of climate change, it seems reasonable to avoid water tanks as energy sources.Gomez Selles, E.; Briones-Hidrovo, A.; Del Teso-March, R.; Uche Marcuello, FJ.; Cabrera Marcet, E. (2021). Rigid Versus Variable Energy Sources in Water-Pressurized Systems: An Economic and Environmental Analysis. Water Resources Management. 35(10):3203-3220. https://doi.org/10.1007/s11269-021-02885-5S320332203510Batchabani E, Fuamba M (2014) Optimal Tank Design in Water Distribution Networks: Review of Literature and Perspectives. J Water Resour Plan Manag 140(2):136–145BOE (Boletín Oficial del Estado) (2020) Circular 3, 2020, de 15 de enero, de la Comisión Nacional de los Mercados y la Competencia, por la que se establece la metodología para el cálculo de los peajes de transporte y distribución de electricidad. BOE, 24 de enero de, 2020. Agencia Estatal Boletín Oficial del Estado, Madrid, pp 6953–6980Cabrera E, Pardo MA, Cabrera Jr. E, Cobacho R (2010) Agua y energía en España. Un reto complejo y fascinante. Ingeniería del Agua 17(3):235–245Cabrera E, Gómez E, Soriano J, del Teso R (2019) Eco-layouts in water distribution networks. J Water Resour Plann Manage 145(1):04018088. https://doi.org/10.1061/(ASCE)WR.1943-5452.0001024Clark RM, Abdesaken F, Boulos PF, Mau RE (1996) Mixing in distribution system storage tanks: Its effect on water quality. J Environ Eng 122(9):814–821Dias AS, Kim H, Sivakumar PK et al (2013) Life cycle assessment: A comparison of manufacturing and remanufacturing processes of a diesel engine. Re-Engineering Manuf Sustain - Proc 20th CIRP Int Conf Life Cycle Eng 675–678EPA (Environmental Protection Agency) (2002) Finished Water Storage Facilities. US Environmental Protection Agency. Office of Ground Water and Drinking Water. WashingtonEverhart GJ (2010) Comparison of life-cycle energy of water storage tanks. University of FloridaGómez E, Cabrera E, Balaguer M, Soriano J (2015) Direct and indirect water supply: An energy assessment. Proc Eng 119:1088–1097. https://doi.org/10.1016/j.proeng.2015.08.941Grundfos (2019) Horizontal split case pumps. Booklet Data. Bjerringbro, DenmarkJens N, Anders N (2014) Water supply in tall buildings: Roof tanks vs. pressurized systems. Grundfos Water Boosting. Grundfos. DenmarkNee AYC (Editor) (2015) Handbook of Manufacturing Engineering and Technology, First. Springer London Heidelberg New York Dordrecht, SingaporePetit-Boix A, Roigé N, de la Fuente A, Pujadas P, Gabarrell X, Rieradevall J, Josa A (2016) Integrated Structural Analysis and Life Cycle Assessment of Equivalent Trench-Pipe Systems for Sewerage. Water Resour Manage 2016(30):1117–1130. https://doi.org/10.1007/s11269-015-1214-5Pillot J, Catel J, Renaud E, Augeard B, Roux P (2016) Up to what point is loss reduction environmentally friendly?: The LCA of loss reduction scenarios in drinking water networks Water Research 104:231–241Raluy RG, Serra L, Uche J, Valero A (2005) Life Cycle Assessment of Water Production Technologies Part 2: Reverse Osmosis Desalination versus the Ebro River Water Transfer. Int J LCA 10(5):346–354Rossman LA, Uber JG, Grayman WM (1995) Modeling disinfectant residuals in drinking-water storage tanks. J Environ Eng 121(10):752Rossman LA (2000) Epanet2. Users Manual. US EPA, Cincinnati. USAStokes J, Horvath A (2006) Life Cycle Energy Assessment of Alternative Water Supply Systems (9 pp). The International Journal of Life Cycle Assessment 11:335–343SV (Sustainability Victoria) (2009) Energy Efficiency Best Practice Guide Pumping System. Sustainability Victoria. Melbourne. AustraliaTangsubkul N, Beavis P, Moore SJ, Lundie S, Waite TD (2005) Life Cycle Assessment of Water Recycling Technology. Water Resour Manage 19:521–537. https://doi.org/10.1007/s11269-005-5602-0Uche J, Martinez A, Castellano C, Subiela V (2013) Life cycle analysis of urban water cycle in two Spanish areas: inland city and island area. Desalination Water Treat 51(1):280–291. https://doi.org/10.1080/19443994.2012.716634Uche J, Martínez-Gracia A, Carmona U (2014) Life Cycle Assessment of the Supply and Use of Water in the Segura Basin Int J Life Cycle Assess 19:688–704. https://doi.org/10.1007/s11367-013-0677-yWalski TM (2000) Hydraulic design of water distribution storage tanks. Water distribution systems handbook, 10, McGraw-Hill, New York, pp 10.1–10.20Walski TM (2012) Planning-level capital cost estimates for pumping. J Water Resources Planning and Management. https://doi.org/10.1061/(ASCE)WR.1943-5452.0000167,307-310WC (Water Corporation) (2017) Design Standard No. DS 61. Water Supply Distribution - Tanks. October 2017. Water Corporation. Osborne Park. AustraliaWernet G, Bauer C, Steubing B, Reinhard J, Moreno-ruiz E, Weidema B (2016) The ecoinvent database version 3 ( part I ): overview and methodology. Int J Life Cycle Assess 3:1218–1230. https://doi.org/10.1007/s11367-016-1087-8WHO (World Health Organization) (2017) Principles and practices of drinking-water chlorination: a guide to strengthening chlorination practices in small-to medium sized. World Health Organization. Regional Office for South East Asia. New Delhi, Indi

An increased dependence on agricultural policies led European grazing agroecosystems to an unsustainability trap

Abstract As all production processes, the agrifood system is driven by energy and materials. The origin and relative contribution of these resources to the system’s functioning determines its sustainability. Here we analyse the evolution of the sustainability of mountain grazing agroecosystems, which are often perceived as a better alternative for animal food production than industrial systems. Specifically, we use Emergy Accounting to assess the dependency of livestock farming on materials and energy in the Spanish Pyrenees along the last three decades, using data collected through face-to-face surveys in 1990, 2004 and 2018. We observe an increase of farm dependence on non-renewable resources, despite longer grazing periods and reduced use of off-farm animal feeds. The increasing inflow of public economic support and services from the socio-economic system (mainly driven by non-renewable sources) transfers its unsustainability to mountain grazing agroecosystems