Increased energy production and environmental deterioration, related to economic growth, are creating a set of interrelated issues for society and development policymakers. The most challenging issues are caused by increased energy consumption and production and their negative influence on the natural environment. Despite globally accepted sustainable development and green energy policies, the implementation of these policies requires long-term, continued efforts and contributions from each country. This is a challenging task, and no unified, generally accepted solution exists for all economic parties. Countries involved in this process have different backgrounds and development histories. Some of them are only consumers of energy resources, while others are producing, consuming, and selling energy resources.

Countries producing and exporting energy resources significantly differ in economic power and the share of energy resources in the GDP. The range of variations is quite large—from oil rent being 0.4% of the GDP for the UK (natural gas rents at 0.17% of the GDP, and total natural resource rents at 0.59% of the GDP) up to 53% for Iraq (natural gas rents at 0.65% of the GDP, and total natural resource rents at 43.4% of the GDP), and 56% for Libya (natural gas rents at 4.58% of the GDP, and total natural resource rents at 61% of the GDP). A small share allows for the relatively swift replacement of traditional energy resources with renewables. However, in the case of a large share, a country needs significant and long-lasting efforts for energy resource replacement. The issue is that in oil-rich countries, energy resources are not only used for generating electricity but are also the main export item and the primary source of hard currency for the country [1].

During the transition period, policy developers must align the current energy policy, the desired policy, and the steps to transition from the current state to the desired one. The transition to a renewable-based energy system is not a one-step process, especially for countries with a high share of oil and gas in their GDP. Addressing the complexities inherent in the transition requires the development of special models and pre-scenarios before creating detailed long-term scenarios and policies. To find a justified solution to the task, it is necessary to analyze approaches for selecting renewables and designing scenarios.

The solution to the renewable energy transition task requires an analysis of multiple alternatives considering a set of contradictory and conflicting beneficial and cost criteria, often in conditions of partial uncertainty. To address this task, various Multiple-Criteria Decision-Making (MCDM) methods have been used.

In some cases, researchers face situations where statistics describing the implementation of renewable energy technologies are limited and non-representative. In such instances, fuzzy models that rely on experts’ knowledge can help compensate for the lack and deficiency of statistical data. Traditionally, models used in the energy sector have been based on precise and exact data, with a primary focus on the efficiency of solutions. However, in areas without well-established decision-making approaches or with limited experience, decision-makers often have to deal with vague information expressed in linguistic form.

2. Fuzzy Method in Decision-Making within the Energy Sector