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  • Environmental Assessment: Life Cycle Assessment of biofuels from seaweed using the MacroFuels concept

    Introduction

    The objective of the MacroFuels project is to advance the technologies for producing liquid transportation biofuels from cultivated seaweed (or macroalgae). As a result, it is hoped that it will be possible to provide more sustainable transport fuels.

    The MacroFuels concept sets out to progress the technologies for producing third generation biofuels from seaweed by assessing current system design concepts. These designs are informed by lab scale testing, field trials and modelling completed within the other work packages of the MacroFuels project. The biofuels production scenarios targeted as part of the MacroFuels concept are:

    • Bio-ethanol via fermentation (EtOH process);

    • Bio-butanol and bioethanol via ABE (acetone, butanol and ethanol) fermentation (ABE Process); and

    • Bio-furanics via biphasic reaction with toluene and water, and reaction with bio-butanol and hydrogen.

    This study reports an environmental life cycle assessment (LCA) of those biofuels which could be produced under the MacroFuels concept. The LCA evaluates the full value chain and thereby provides a better understanding of the potential environmental impacts of the large-scale cultivation of seaweed and its use as a feedstock for the production of biofuels.

    A key driver for the development of biofuels in Europe is the renewable Energy Directive (2018/2001/EC) (the RED). The RED sets a target of 14% of energy for transport to come from renewable sources by 2030. For a biofuel to count towards this target, it must fulfil certain sustainability criteria set out in the RED with respect to greenhouse gas (GHG) emissions and should be identified as no / low risk for additional impacts from indirect land use change. Indirect land use change can increase the net GHG emissions from terrestrial crops used as biofuels, but seaweed is seen as a low risk crop in this context, as it is grown in the sea and will not displace land used to grow food.

    Goal and Scope of the Study

    The goal of this LCA was to conduct a ‘cradle-to-grave’ assessment of the MacroFuels concept. This will inform its future development by appraising the potential environmental impact of producing biofuels from seaweed for use as transport fuels and allow comparison of the calculated GHG emissions of these fuels with reported values for those produced from other sources.

    The objectives of the LCA are as follows:

    1. To increase MacroFuels’ understanding of the life cycle environmental impacts of the biofuels from seaweed concept;

    2. Identify where the main environmental impacts occur (the so-called ‘hotspots’) in the full value chain for the production of biofuels from seaweed to support the design of systems for seaweed cultivation and processing to biofuel;

    3. Compare the life cycle impacts of the ethanol, butanol and furanic fuels produced; and

    4. Benchmark the biofuels assessed under the MacroFuels project against:

    a. Equivalent conventional, fossil-based, fuels and currently available biofuels; and

    b. Sustainability criteria for GHG emissions under the Renewable Energy Directive (2018/2001).

    Product System Studied and Functional Unit

    The study investigates the potential environmental impacts of the following products produced via the three processes outlined above. An important step in both the EtOH and ABE processes is the hydrolysis of the seaweed prior to fermentation. This can be completed by either acid hydrolysis or enzyme hydrolysis and both processes are considered, as follows.

    • Ethanol (EtOH process - acid hydrolysis);

    • Ethanol (EtOH process - enzyme hydrolysis);

    • Ethanol (ABE process - acid hydrolysis);

    • Ethanol (ABE process - enzyme hydrolysis);

    • Butanol (ABE process - acid hydrolysis);

    • Butanol (ABE process - enzyme hydrolysis);

    • Furanics fuel additive; and

    • Furanics fuel (10%) / bio-butanol (90%) blend

    The functional unit this study is defined as:

    1 MJ of biofuel used as transport fuel in an internal combustion engine.

    Life Cycle Stages Considered

    The LCA carried out was ‘cradle-to-grave’. This means that all significant life cycle stages associated with the product systems studied were considered, from raw materials, through processing and production, to distribution, use, waste collection, recycling or management at end of life.

    Energy and material inputs were traced back to the extraction of resources, and emissions and wastes from each life cycle stage were quantified. Figure 0-1 shows the system boundary of the LCA.

    Figure 0-1 System boundaries of LCA based on life cycle of biofuel from seaweed according to the MacroFuels concept

    The Macrofuels concept considers a biorefinery with a processing capacity of 1.2 Mtonne seaweed (dw) per year, as this equivalent to that of an existing large bioethanol plant in the port of Rotterdam, the Netherlands. 

    Seaweed cultivation

    The study assumes that only brown seaweed (Saccharina latissimi) is used as feedstock in the EtOH and ABE processes and only red seaweed (Palmaria palmate) is used as feedstock for the furanics process. It has been assumed that two harvests a year of these crops is possible. The cultivation systems and yields for both seaweeds are assumed to be the same.

    The design of the seaweed cultivation system was based on a concept published in open literature (Groenendaal, Vandendaele, & Vroman, 2017; Sioen, 2015). The growing substrate for the seaweed is sheetnets, made from polyester non-woven material, held horizontally in the water by chains and bouys and arranged in repeating segments for a total effective area of the seaweed field of 18,460 ha. This will produce 1.2 Mtonne seaweed (dw) per year for the biorefinery.

    Processing seaweed to biofuel

    The data for processing seaweed to biofuel have been sourced from MacroFuels deliverable 6.2, Techno-economic Evaluation and Health and Safety Risk Assessment. Table 0-1below summarises the production processes for each scenario considered in the Macrofuels concept.

    Author(s): Donald Reid , Jed Mawdsley, Jonna Fry, Michael Collins, Simon Aumônier

  • Environmental Deterioration of Fish Farms in Japanese Enclosed Bays and Measures for their Environmental Management

    Fish farming using net pens in some Japanese enclosed bays started in the late 1950s and was referred to as “the conversion of catching fisheries to rearing fisheries.” Net pen aquaculture has increased rapidly in popularity in the enclosed coastal areas of Japan since the 1970s. Total yields from net pen aquaculture recently reached approximately 270,000 metric tons, the majority of which is contributed by the culture of yellowtail, salmon, and red sea bream (Shirota 1990, MAFF 2005). A major problem of using net pens that has yet to be solved is that the fish are reared at extremely high densities with limited space and they require large amounts of food. Dissolved oxygen (DO) tends to decrease in the water in the net pens during the night due to respiration of the fish and the cessation of photosynthetic activities of phytoplankton (Hirata and Kadowaki 1990). Only 10% - 20% of the food fed to cultured fish contributes to their somatic growth. The remainder tends to be discharged as waste in the form of organic particles and inorganic nutrients outside the net pens, often causing organic enrichment of the sediment just below the fish farm and eutrophication of the water in the coves and bays where the fish farms are located (Tsutsumi and Kikuchi 1983; Hirata et al. 1994).

    Author(s): Hiroaki Tsutsumi

  • Environmental eco-friendly marine resource macro algae (Seaweeds): an omnipotent source for value added products and its applications - A review

    The consequent reduction of land resources by human activities such as pollution, over exploitation, industrialization, migration etc., has lead man to search for other alternative ways to meet the demands for well-being. When this has been the existing situation in most of the developing countries, kelp forest resources like seaweeds which are known for its potentially strong bioactive compounds can be the best fit to fulfill numerous requirements such as nutritious food, biofuels, biofertilizer and pharmaceuticals to cure different diseases and other industrial applications. From the history till date seaweed has been employed in various sectors like food, pharmaceuticals, agriculture, waste water treatment and so on. Malnutrition and poverty have become the major issue in many of the developing nations, hale and healthy life can be guaranteed by seaweed food products and also people can be self- employed. Besides many research works done regarding seaweeds this review provides a collective idea about the potentials and wide range applications of seaweed, a marine macroalgae.

    Author(s): B.Bharathiraja, P. Devaki, S. Dheepa, R. Mageshwari, J. Jayamuthunagai, M. Chakravarthy, D. Yuvaraj, R. Praveenkumar

  • Environmental effects on growth and fatty acids in three isolates of Derbesia tenuissima (Bryopsidales, Chlorophyta)

    We quantified the effects of temperature, light and nitrogen availability on the growth and fatty acids (FAs) in three isolates of the green seaweed Derbesia tenuissima to portion the environmental and the genotypic (between isolates) components of variation. Growth ranged from 13 to 33% day−1 and 27% of the variation was between isolates and 48% of variation was explained by light intensity. The content of total FA (TFA) ranged from 34 to 55 mg g−1 dw and 49% of the variation was between isolates, while the TFA was 20% lower in the high light and low nitrogen treatment combination. The proportion of omega-3 polyunsaturated FA (PUFA(n-3)) ranged from 31 to 46% of TFA with a strong interactive effect of isolate and temperature. In two isolates, the proportion of PUFA(n-3) increased by 20% under cultivation at low temperature while in a third isolate temperature had no effect. Increases in PUFA(n-3) occurred with a stable content of TFA and high growth rates, leading to net increases in PUFA(n-3) productivity in two isolates. This research highlights the potential for environmental manipulation and strain selection to further improve the productivity and quality of fatty acids in seaweed.

    Author(s): Björn J. Gosch, Rebecca J. Lawton, Nicholas A. Paul, Rocky de Nys, Marie Magnusson

  • Environmental factors influencing the growth of Gracilaria edulis in culture

    The present investigation indicates that G. edulis can be successfully cultivated on commercial scale in the nearshore areas of Gulf of Mannar during the five months period from November to March when the sea is calm. The shallow waters near CMFRI fish farm in Palk Bay are not suitable for G. edulis cultivation as the growth of the plant was affected by various environmental factors mentioned above. The culture experiments of G. edulis conducted earlier by the Central Marine Fisheries Research Institute in 3 - 4 m depth area at Palk Bay near CMFRI fish farm showed good growth of plants as there was less sedimentation, fouling organisms and predators. Hence G. edulis could be cultivated in deep waters in Palk Bay side and attempts may also be made to culture G. edulis in shallow waters at other areas of Palk Bay in order to select the suitable culture sites and period of good growth.

    Author(s): Kaliaperumal, N, Chennubhotla, V S Krishnamurthy, Kalimuthu, S, Ramalingam, J R, Muniyandi, K

  • Environmental Impact on Seaweed Phenolic Production and Activity: An Important Step for Compound Exploitation

     Seaweeds are a potential source of bioactive compounds that are useful for biotechnological applications and can be employed in different industrial areas in order to replace synthetic compounds with components of natural origin. Diverse studies demonstrate that there is a solid ground for the exploitation of seaweed bioactive compounds in order to prevent illness and to ensure a better and healthier lifestyle. Among the bioactive algal molecules, phenolic compounds are produced as secondary metabolites with beneficial effects on plants, and also on human beings and animals, due to their inherent bioactive properties, which exert antioxidant, antiviral, and antimicrobial activities. The use of phenolic compounds in pharmaceutical, nutraceutical, cosmetics, and food industries may provide outcomes that could enhance human health. Through the production of healthy foods and natural drugs, bioactive compounds from seaweeds can help with the treatment of human diseases. This review aims to highlight the importance of phenolic compounds from seaweeds, the scope of their production in nature and the impact that these compounds can have on human and animal health through nutraceutical and pharmaceutical products.

    Author(s): Silvia Lomartire, João Cotas, Diana Pacheco, João Carlos Marques, Leonel Pereira, Ana M. M. Gonçalves

  • Environmental Impacts of Experimental Production of Lactic Acid for Bioplastics from Ulva spp.

    An exploratory Life Cycle Assessment (LCA) was carried out to provide insight into the environmental impacts of using the green seaweed Ulva spp. as a feedstock, for production of bioplastic. The study focused on the production of lactic acid as a precursor of polylactic acid. The study was on the production process: (1) The cultivation of Ulva spp., in an Integrated Multitrophic Aquaculture system; (2) the processing of the biomass for solubilization of sugars; (3) the fermentation of the sugars to lactic acid; (4) the isolation of lactic acid from fermentation broth. The study identified environmental hotspots and compared an experimental seaweed production chain with conventional feedstocks. The main hotspot is derived from electricity consumption during seaweed cultivation. The impact of electricity consumption can be lowered by reducing energy use and sourcing renewable energy, and by improving the material efficiency in the product chain. To improve understanding of the process of production’s environmental impacts, future studies should broaden the system boundaries and scope of sustainability issues included in the environmental assessment.

    Author(s): Roel J. K. Helmes, Ana M. López-Contreras, Maud Benoit, Helena Abreu, Julie Maguire, Fiona Moejes, Sander W. K. van den Burg

  • Environmental impacts of protein-production from farmed seaweed: Comparison of possible scenarios in Norway

    As the demand for proteins increases with growing populations, farmed seaweed is a potential option for use directly as an ingredient for food, feed, or other applications, as it does not require agricultural areas. In this study, a life cycle assessment was utilised to calculate the environmental performance and evaluate possible improvements of the entire value chain from production of sugar kelp seedings to extracted protein. The impacts of both technical- and biological factors on the environmental outcomes were examined, and sensitivity and uncertainty analyses were conducted to analyse the impact of the uncertainty of the input variables on the variance of the environmental impact results of seaweed protein production. The current production of seaweed protein was found to have a global warming potential (GWP) that is four times higher than that of soy protein from Brazil. Further, of the 23 scenarios modelled, two resulted in lower GWPs and energy consumption per kg of seaweed protein relative to soy protein. These results present possibilities for improving the environmental impact of seaweed protein production. The most important variables for producing seaweed protein with low environmental impact are the source of drying energy for seaweed, followed by a high protein content in the dry matter, and a high dry matter in the harvested seaweed. In the two best scenarios modelled in this study, the dry matter content was 20% and the protein content 19.2% and 24.3% in dry matter. This resulted in a lower environmental impact for seaweed protein production than that of soy protein from Brazil. These scenarios should be the basis for a more environmental protein production in the future.

    Author(s): Matthias Koesling, Nina P. Kvadsheim, Jon Halfdanarson, Jan Emblemsvåg, Celine Rebours

  • Environmental Impacts of Seaweed Farming in the Tropics

    Seaweeds are multicellular algae that occur in marine and brackish-water and that, at some stage in their lives, are attached to a substrate. World-wide there are approximately 10,000 species of seaweeds and at least 221 species of seaweed are utilised by humans. 145 species are used for food while 101 species are used for phycocolloid production (i.e. alginates, agar and carrageenan). Each year around 2 million tonnes dry weight (approximately 13 million tonnes fresh weight) of seaweed is collected at a value of in excess of US$6.2 billion. 50% of this seaweed (by volume) is cultured and approximately 10% of cultured seaweed comes originates in the tropics. In the tropics the vast majority of seaweed farmed is of the genera Eucheuma or Kappaphycus. Approximately 120,000 tonnes dry weight (t dw) of Eucheuma/Kappaphycus are produced annually compared with approximately 15,500 t dw of Gracilaria and 800 t dw of Caulerpa (Zemke-White and Ohno 1999). Most of the Eucheuma/Kappaphucus is farmed in the Philippines (~95,000 t dw), followed by Indonesia (22,000 t dw), Zanzibar (4,000 t dw), Malaysia (800 t dw), Kiribati and Madagascar (both around 400 t dw). Most of the Gracilaria is farmed in Indonesia (~13,500 t dw) and almost all of the Caulerpa is farmed in the Philippines. 

    Author(s): W. Lindsey Zemke-White

  • Environmental life cycle assessment of biogas production from marine macroalgal feedstock for the substitution of energy crops

    The central objective of this paper is to evaluate the production of biogas by the substitution of energy crops with marine macroalgae: mixture of brown (20%) and red algae (80%) as feedstock in an industrial scale biogas plant. This plant operates with the co-digestion of maize (27%), grass (54%), rye (8%) and chicken manure (11) and produces 500 kWh energy. In order to assess environmental friendliness, a life cycle assessment was performed by using the software Simapro. Potential environmental impact categories under investigation were global warming, acidification, eutrophication and land transformation potential. Our results determine the affirmative impact of the codigestion of algae with chicken manure on the emission reductions: 52%, 83%, 41% and 8% lower global warming, acidification, eutrophication and land transformation potentials, respectively per 1 MJ of energy generation, moreover, 84% and 6% lower acidification and land transformation potentials per kg of feedstock.

    Author(s): Funda Cansu Ertem, Peter Neubauer, Stefan Junne

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