Multi-criteria decision analysis (MCDA) is widely used to solve various decision problems through alternative evaluation. MCDA methods can be used in every field that can define a problem, alternatives and criteria. However, finding the appropriate method can influence the results, in this research five MCDA methods have been tested on the renewable energy sector in Latvia to find the best alternative. The main results showed that TOPSIS, VIKOR and PROMETHEE-GAIA have similar priority selection and the highest ranking was selected for hydropower plant, but MULTIMOORA and COPRAS results were beneficial to Solar PV.

Sustainability targets set by the United Nations, such as Zero Hunger by 2030, encourage the search for innovative solutions to enhance food production while preserving the environment. Alternative protein sources for feed, while conventional resources like soymeal and fishmeal become more expensive and scarcer, is one of the possibilities. Studies on substituting fishmeal with insect meal show promising results in terms of animal growth and feed efficiency. This paper aims to assess the socio-economic benefits and costs of insect meal substituting fishmeal in feed and to highlight the factors influencing performance most. The study evaluates the economic value of insect-based products, waste reduction, and reduced greenhouse gas emissions as socio-economic benefits. It combines empirical data derived from laboratory trials and two case studies covering black soldier fly (Hermetia illucens) and yellow mealworm (Tenebrio molitor). Current analyses reveal negative socio-economic balances, emphasizing that reduction of operating and investment costs through upscaling and technological advancements can give a positive move, as well as factors such as current market valuations for nutrients can change significantly. Thus, a negative balance at the moment does not mean that insect rearing, and larva processing are not desirable from a long-term socio-economic perspective.

This study investigates available resources that has not been used or is used with low added value, such as woody crops, forest residues and invasive species possibilities in case of cellulosic products. Main aspect is this study is market outlook, to see if the products can have positive market sales if produced. Resource have been selected by availability and current usage and properties they contain. Products have been chosen the most basic, to see is there possibility to enter an existing cellulose product markets. GE/McKinsey matrix have been used for clear visual decision making. The results show that only two out of seven products has a potential in international market.

In order to enforce the concepts of bioeconomy and the circular economy, the use of a bottom-up approach at the national level has been proposed: to start at the level of a small region, encourage its development, considering its specific capacities and resources, rather than applying generalized assumptions at a national or international level. Therefore, this study has been carried out with an aim to develop a methodology for the assessment of small rural areas in the context of the circular economy and bioeconomy, in order to advance the development of these regions in an effective way, using the existing bioresources comprehensively. The methodology is based on the identification of existing and potential bioeconomy flows (land and its use, bioresources, human resources, employment and business), the identification of the strengths of their interaction and compare these with the situation at the regional and national levels in order to identify the specific region’s current situation in the bioeconomy and identify more forward-looking directions for development. Several methods are integrated and interlinked in the methodology – indicator analysis, correlation and regression analysis, and heat map tables. The methodology is approbated on one case study – Aizkraukle region – a small rural region in Latvia. During the research recommendations for the development of the circular economy and bioeconomy for the case study have been elaborated.