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Renewable energy sources (RES) are the key element of sustainable energy systems. To accommodate the intermittency of wind (and solar) electricity generation, energy storage is critical. The aim of the study was to evaluate the potential of wind energy storage in the existing hydropower plant reservoirs in Latvia with the pumped hydroelectric energy storage (PHES) technology, considering the current and projected future wind energy capacities. An algorithm was developed and used for data aggregation and analysis, calculations, and forecasting. The three River Daugava hydroelectric power plants are the largest electricity producers in Latvia, and their generation capacity depends on seasonal variations. Currently, Latvia's electricity generation from RES is the highest during the spring season when maximum hydropower potential is utilized. However, wind energy has a potential to grow and could supplement hydropower throughout the year. Decreasing the existing administrative procedure heaviness to faster achieve the climate neutrality targets and energy autonomy by increasing RES development in Latvia is a way to create sustainable energy production. A rational future scenario in Latvia is to expand wind parks and integrate pumped hydroelectric energy storage systems in the existing cascade hydropower plants.

More production is needed as fish consumption increases. The increasing demand for fish also has implications for fish feed, the efficiency of its production and sustainability. Three protein alternatives – Black Soldier Fly, Yellow Mealworm, and Soybean – are compared to assess the sustainability of raw materials and their environmental impact. Each alternative has advantages and disadvantages. The advantages of Black Soldier fly and Yellow Mealworm are a valuable source of protein, sustainable growth (as the feed can be used in food waste) and no need for arable land. The disadvantages of Black Soldier fly and Yellow Mealworm are cost, unbalanced diets can adversely affect growth, and the nutritional impact on fish varies depending on the species of fly or mealworm. The advantages of soybeans are price, availability, and high protein content, while the disadvantages are the lack of essential amino acids, which affect the quality of the fish, and poor taste. An LCA study has been carried out on the proteins of black soldier fly, yellow mealworm and soybean. The most important impact categories from the PEFCR are climate change, particulate matter, acidification, land use, terrestrial eutrophication, and water use. The total single point value for the Black Soldier fly protein is 1.43E+01 µPt, the Yellow mealworm protein is 3.89E+02 µPt and the Soybean protein is 9.72E+01 µPt. The significant effect is due to the electricity consumption and the ingredients used in the feed. Sensitivity analysis was carried out for Black Soldier fly protein and Yellow Mealworm protein production where feed formulation was varied. In both sensitivity analyses, the lower environmental impact is from the new feed structure, which may be due to the use of food waste and wheat as feed ingredients in the new feed structure.

Sustainable development in the agriculture sector can be boosted by integrating a sustainable bioeconomy and transforming renewable resources into added-value products. There are various methods to determine, measure, and compare the extent of sustainability. We promote the bioeconomy concept by utilizing agricultural waste in biopolymers considering the sustainable development in the agriculture sector. This research aims to evaluate biopolymer alternatives based on sustainability criteria and indicators using the integrated multi-criteria decision analysis approach under the sustainability umbrella. We evaluated the PLA, PHA/PHB, starch, protein, and cellulose-based biopolymers. As a result, the cellulose-based biopolymer shows the best performance. The research findings provide valuable information to establish a sustainable pathway for biopolymer production for industries.

The share of renewable energy in heat and power generation is expected to increase significantly and reach record levels in the coming decades. As a result, emerging energy storage technologies will be key elements in balancing the energy system. To compensate the variability and non-controllability of seasonally generated renewable energy (RES) (daily fluctuations in solar radiation intensity, wind speed, etc.) development of sufficient energy storage infrastructure in the regions will play a major role in transforming RES supply potential into reality. However, local public authorities that are responsible for creating an enabling policy environment for RES infrastructure development in regions encounter numerous challenges and uncertainties in deploying sufficient energy accumulation that often remain unanswered due to a lack of knowledge and on-site capacity, which in turn significantly hinders the regional path to climate neutrality. In this study, the PESLTE analytical framework and composite index methodology is applied to examine the multidimensional factors that influence the deployment of renewable energy storage technologies in municipalities: political, economic, social, legal, technological, and environmental. Developed model is approbated in a case study in a Latvian municipality where four different alternative energy storage technologies are compared: batteries for electricity storage, thermal energy storage, energy storage in a form of hydrogen, and energy storage in a form of biomethane.

Global annual textile consumption has doubled in the last two decades and is expected to keep increasing. Since the textile system operates primarily in a linear way, it is highly polluting and creates a lot of waste. But nevertheless, it has a high potential for circularity since most textile products can be recycled or reused. Today most of the waste ends up in landfills, and less than 1 % is recycled back into textiles. This study aims to gather information and evaluate which textile product group has the highest potential for circular economy growth. It covers three main textile product streams: fashion, home, and technical textiles. The groups were compared using fifteen criteria: environmental impact, washes, landfilled waste, recycled waste, origin of fabric, projected lifetime, market demand, production volume, international trade, labour productivity, value added, energy efficiency of production technologies, innovation capacity, employment, and enterprises. Input values have been found for each sustainability indicator by using and mathematically transforming data from the scientific literature. The evaluation method used in this study was multi-criteria decision analysis. The results indicated that the fashion textile group has the most significant potential for circular economy development, mainly because it is the largest textile product stream, and the development of a circular economy could be cost-effective.

The marketability of fish depends on the visual appearance of the fish, so the feed ingredient pigment contributes to the nutritional value and visual appearance of the product. The benefits of a natural pigment derived from microalgae are the ecological benefits, as the culture can fix carbon and release oxygen. The economic aspect is a benefit of synthetic pigments. The Life Cycle Assessment (LCA) method was used to determine the environmental impact of natural and synthetic pigments. The results obtained from the LCA are expressed according to the impact categories defined by the Product Environmental Footprint Category Rules (PEFCR). A sensitivity analysis was also carried out comparing the environmental impacts of electricity generated with hydropower or using a field mix from Norway for the natural pigment. The total single score value for natural pigment is 1.17E+01 mPt and the largest impact is from sodium nitrate and electricity. The sensitivity analysis results for electricity from the country mix is 1.82E+01 mPt. The total single score value for synthetic pigment is 8.24E−01 mPt, with the largest impact from methanol. Synthetic pigments have a lower environmental impact than natural pigments, but a sensitivity analysis shows that the environmental impact can be reduced by choosing an alternative to electricity. It should be noted that the comparison presented represents a general comparison of alternatives, as the input data is derived from a literature review.

To achieve the climate targets set by 2030 and become climate neutral by 2050, each Member State must develop a National Energy and Climate Plan (hereinafter NECP) containing practical and effective measures to achieve the targets. The research sought a connection between the measures or action lines in the Latvian NECP related to agriculture and forestry, the European Green Deal goals and related strategies. The effectiveness of the agricultural and forestry measures defined in the Latvian NECP was evaluated by defining appropriate indicators, an expert survey and a composite sustainability index. The results show that the effectiveness of agricultural and forestry measures is most influenced by quality, financing, and specificity factors. The lowest-scoring measures were specific measures whose impacts cannot be measured and are not explicitly mentioned in the European Green Deal. Therefore, the description of the measures should be more detailed, with specific activities, indicators to be achieved, and amounts and funding sources planned for each activity.

There is no one unique parameter with value which can represent bioeconomy sustainability and development. However, many different parameters can be used to describe the economic, social, environmental technological aspects of bioeconomy. The paper present combined approach with using multi criteria decision analysis (MCDA) and fuzzy cognitive map (FCM) analysis methods for bioeconomy sustainability index. Study describe methodology of fuzzy cognitive map developing, including expert involving, obtained data from survey combination to bioeconomy indicators and categories. The weight of selected FCM components were normalized using MCDA method. The critical points of the applied method and opportunities for improvement have been identified. The role of respondents in the results is also considered.