This article analyses the influence of supporting scheme variants on the profitability of a projected investment of residential photovoltaic systems. The focus of the paper lies in evaluating the feasibility for the power system of solar power generation technologies to achieve a balance between energy generation and support costs in a more efficient way. The case study is based on a year-long time series of examples with an hourly resolution of electricity prices from the Nord Pool power market, in addition to the power demand and solar generation of Latvian prosumers. Electric energy generation and the consumption of big data from more than 100 clients were collected. Based on these data, we predict the processes for the next 25 years, and we estimate economic indicators using a detailed description of the net metering billing system and the Monte-Carlo method. A recommendation to change the current net system to a superior one, taking into account the market cost of energy, concludes the paper.

Biomethane is one of the most promising renewable gases (hereafter – RG) – a flexible and easily storable fuel, and, when used along with the natural gas in any mixing proportion, no adjustments on equipment designed to use natural gas are required. In regions where natural gas grids already exist, there is a system suitable for distribution of the biomethane as well. Moreover, improving energy efficiency and sustainability of the gas infrastructure, it can be used as total substitute for natural gas. Since it has the same chemical properties as natural gas, with methane content level greater than 96 %, biomethane is suitable both for heat and electricity generation, and the use in transport. Biomethane is injected into the natural gas networks of many Member States of the European Union (hereafter – the EU) on a regular basis for more than a decade, with the Netherlands, Germany, Austria, Sweden and France being among pioneers in this field. In most early cases, permission to inject biomethane into the natural gas grids came as part of a policy to decarbonize the road transport sector and was granted on a case-by-case basis. The intention to legally frame and standardise the EU’s biomethane injection into the natural gas networks came much later and was fulfilled in the second half of the present decade. This paper addresses the biomethane injection into the natural gas grids in some EU countries, highlights a few crucial aspects in this process, including but not limited to trends in standardisation and legal framework, injection conditions and pressure levels, as well as centralised biogas feedstock collection points and the biomethane injection facilities. In a wider context, the paper deals with the role of biomethane in the EU energy transition and further use of the existing natural gas networks.

The purpose of this study was to analyze the economical suitability of numerous on-site renewable electricity generation technologies which were intended to be used in a recently built industrial facility designed and utilized as a warehouse. The facility was located in the vicinity of Riga, Latvia. Data were collected and calculations were performed within the scope of the project “Mitigating Energy Poverty through Innovative Solutions” as part of several planned activities to address the broad spectrum of energy poverty and self-reliance issues in both the residential sector and small-scale industrial facilities. During the project, evaluations of various renewable energy technologies, including PV installations, wind energy installations, battery storage solutions, and hybrid technologies, were carried out. The aim of these evaluations was to develop an electricity production–consumption model for efficient and cost-effective energy use and to reduce greenhouse gas emissions from the test facility. A model was created and subsequent research scenarios were developed based on a payback period instead of the net present value criterion. The project was carried out over several steps to develop a calculation methodology. The open access databases of energy resource providers were used to evaluate statistical data and make forecasts for the analysis of the electricity consumption of companies. MATLAB/Simulink 23/2 was used for the data analysis, and the H-TEC method was employed. This made it possible to modulate the required production capacity as the model allowed for the addition of new modules to modules already installed. The project results proved that despite high initial investment costs, renewable energy sources and efficient storage systems can provide cost-effective solutions and reduce dependence on fossil fuels in the long term.

Hydrogen is the most abundant chemical element on the Earth, and it has really a wide variety of applications, starting from use in refining, petrochemical industry, steel manufacturing, and ending with use in energy production and renewable gas (hereinafter – RG) blending for gradual replacement of natural gas in all sectors of the national economy. Being practically emission-free, if produced in sustainable way or from renewable energy sources (hereinafter – RES), hydrogen is regarded as one of the most promising energy sources for decarbonisation of practically the entire segment of industrial and energy production. Growing pressure of the European climate neutrality targets has triggered special interest in production, use, storage and transportation of hydrogen – especially the green one, which can be used in at least four fundamental ways: as a basic material, a fuel, an energy carrier and an energy storage medium. In the context of sector coupling, however, hydrogen facilitates decarbonisation of those industrial processes and economic sectors in which carbon dioxide (hereinafter – CO₂) emissions can either not be reduced by electrification or this reduction would be minimal and linked to very high implementation costs. At the same time, development of an extensive hydrogen economy is the key to the achievement of the European climate protection targets, with the European Commission’s (hereinafter – EC) Hydrogen Strategy, a framework created in 2020 to develop and promote sustainable hydrogen economy in the European Union (hereinafter – EU), in its centre. Green hydrogen also will take its legitimate place in the gaseous fuel diversification risk management strategy, as this gaseous fuel is not only one of the most perspective future energy sources, but also one of the most volatile and demanding sources. In the process of gaseous fuel diversification in the EU and worldwide, new logistical chains and supply – demand networks of green hydrogen will emerge. Therefore, adequate addressing of potential challenges of this new regional and global production, delivery and consumption framework will be of utmost importance for secure, safe and predictable functioning of future energy systems.

The existing European Union (EU) natural gas network provides large capacity to integrate renewable (RGs) and low-carbon gases. Today, hydrogen contributes only a few percent to Europe’s energy consumption and is almost exclusively produced from fossil fuels and used in the industry. Nevertheless, hydrogen has a significant role to play in emission reduction in hard-to-decarbonize sectors, in particular, as a fuel in transport applications and as a fuel or feedstock in certain industrial processes (steel, refining or chemical industries, the production of “green fertilizers”). Carbon dioxide (CO₂) in reaction with hydrogen can also be further processed into synthetic fuels, such as synthetic kerosene in aviation. In addition, hydrogen brings other environmental co-benefits when used as fuel, such as the lack of air pollutant emissions. However, in transitional phase from fossil to RG, namely, renewable or green hydrogen, natural gas/biomethane and hydrogen blends, are needed to gradually replace natural in existing gas transmission and distribution networks. The gas networks are believed to be able to use natural gas/biomethane and hydrogen blends with 5–20 % of hydrogen by volume. Most systems and applications are able to handle it without a need for major infrastructure upgrades or end-use appliance retrofits or replacements. The promotion of hydrogen network such as European Hydrogen backbone (EHB) is gaining momentum in Europe. To decarbonize the natural gas grids, the threshold of hydrogen in the existing grid systems must be increased, which can be done by means of wider natural gas/biomethane and hydrogen blending and simultaneous transportation in currently operational gas networks.

The role of demand response increases considerably with a higher share of renewable energy sources in the energy mix, characterized with more frequent energy market price fluctuations due to mismatch between uncontrollable weather-dependent production and currently relatively inflexible energy consumption. Reallocation of energy consumption from high-price hours to lower price hours helps to avoid extra costs to the entire economy and ensures the possibility to minimize fossil-based energy generation, therefore contributing to the achievement of zero-emission goals. The research aims to analyze involvement stimulating factors of demand-side management and demand response from the angles of various energy sector participants, identifying barriers and enabling a successful implementation and wider development of this important energy transition facilitator. The qualitative methods are as follows: utilizing the conducted literature review; and scrutinizing scientific publications, reports and legal acts. As a result, the authors point out the five main aspects: pricing mechanisms, incentives, technology, government regulation and customer awareness. Demand response requires spectacular human and technological resources and administrative, financial and educational efforts. However, the demand response addresses many challenges, such as cost savings, innovation, integration of renewable energy sources, effective, stable and safe power grid performance, reduced need for costly infrastructure modifications, and greenhouse gas emission reduction. The abovementioned benefits influence what the demand-response brings, and are crucial for modern society and a successful energy transition.