The abandonment of conventional sources in favor of energy from renewable energy sources (RES) has a global dimension, and the dynamic increase in the share of energy from photovoltaic systems in the energy mix of many countries results from the possibility of obtaining it both on a small scale (micro-installations) and as part of economic investments (photovoltaic power plants). The study aimed to assess the economic efficiency of 22 photovoltaic farms located in northeastern Poland. The research covered 5 solar power plants with a capacity of up to 799 kWp (I), 13 between 800 and 1100 kWp (II), and 4 installations of 1.98 MWp (III). The evaluation was based on net present value (NPV), internal rate of return (IRR), payback period (PP), profitability index (PI), accounting rate of return (ARR). Additionally, a sensitivity analysis was carried out regarding the value of economic indicators. The analysis shows that all studied PV farms are economically justified investments (NPV > 0) regardless of the adopted scenario. Solar power plants of the largest analyzed capacity (group III) resulted in being the most profitable ones, but no linear relationship between the level of productivity and profitability was established. Due to the large variation in terrain shape in northeastern Poland, landscape value and social benefits, which are difficult to assess, the support system for investments regarding the construction of photovoltaic power plants proved to be the most effective in group I.

The idea of “good quality of life” cities was introduced to Poland in 2006, when the Polish National Cittaslow City Network was founded i.a. by Lidzbark Warmiński. In the context of popularizing the idea—slow-style of life—it was decided to undertake research aimed at identifying the influence of the Cittaslow concept on the initiation of actions that have a positive impact on local sustainable development. Referring to the main objective of the study, the hypothesis was accepted stating that membership in the Cittaslow network has a positive impact on the local development of the city, as it is a source of new projects undertaken by the authorities that improve the quality of life of the inhabitants and at the same time are implemented with the participation of local communities. The hypothesis was verified in a survey conducted in 2017 and 2019 among the residents of the city of Lidzbark Warmiński, using a questionnaire. As the research shows and the research of other authors confirms, the quality of life in cities belonging to the Cittaslow network has significantly improved over the last few years. Residents also assessed the degree of satisfaction of their needs and the level of development of the local city against other cities in the region. Obtaining the opinion of residents regarding the Cittaslow network as a direction of local sustainable development, as well as assessing its impact on the quality of life of the urban community turned out to be important from the perspective of further analysis. This issue is important because the idea of the international association Cittaslow is to promote the potential of smaller towns as an alternative to living in big cities, the rush and progressive globalization. Cities in the network are committed to sustainable development by shaping a conscious urban policy, the right relationship between economic growth, the environment and improving the quality of life of residents.

Environmental Biotechnology deals with preservation and restoration of fauna, flora, and their environment. The utilisation of environmental biotechnology has significantly affected the world and will be one of the most valuable tools for improving the quality of life for future generations b y providing cost effective mechanisms for preserving and restoring natural resources. Biotechnology will also revolutionise many industrial processes by providing the ability to produce energy and chemicals through green processes that will minimise the impact of industrial activities on the environment and reduce the world's dependence on non-renewable energy resources. It will also enable the use of biological systems for the remediation of contaminated water and soils that result from many anthropogenic activities. The journal is devoted to biotechnological processes that preserve, protect and restore nature, mainly: • cytogenetic and molecular diagnostics of living andancient organisms,

In terms of supporting the development of green economy, it is important to understand the role of environment in stimulating its development. The results of an empirical study conducted in 2017 on a randomly selected sample of 578 enterprises of the SME sector, directly related to green economy, indicated that not only macroenvironment (the policy pursued, the creation of global institutional solutions supporting the development of resource-efficient technologies) but also meso-and microenvironment affected the development of green economy. A major role in this regard is served by the activity of local government units and by the activities of non-governmental organisations that form the institutional environment of enterprises. These institutions have tools and instruments, which they can use to stimulate the process of "greening" of the local economy.

The study analyzed the structure of water shortages in plant crops and the available groundwater resources that can be used to satisfy these needs. The research was carried out in Braniewo poviat, which can be considered representative of the conditions of Central and Eastern Europe. A clear upward trend in the temperature value was observed, which influenced the changes in the duration of thermal seasons and agricultural periods. It also increases the intensity of the evapotranspiration process, which results in the reduction of water resources. The presence of significant water shortages, especially in the cultivation of root crops, such as, for example, late potato or sugar beet, justifies the need to irrigate these plants. Due to unevenly distributed surface water resources, groundwater is used as a source of irrigation. It was found that in the case of many crops, the areas with the greatest water shortages were those with average or high abundance in available groundwater. When indicating the possibility of abstracting large amounts of groundwater for use in plant production in Braniewo poviat, one should consider the fact that, in the long term, their exploitation may cause negative environmental effects.