**1. Introduction**

The growing impact of the ecological footprint on the environment from activities in the energy sector indicates the need to modernise and increase the level of implementation of environmentally sustainable technologies, which makes the search for ways to

**Citation:** Koval, V.; Borodina, O.; Lomachynska, I.; Olczak, P.; Mumladze, A.; Matuszewska, D. Model Analysis of Eco-Innovation for National Decarbonisation Transition in Integrated European Energy System. *Energies* **2022**, *15*, 3306. https://doi.org/10.3390/en15093306

Academic Editor: Peter V. Schaeffer

Received: 12 April 2022 Accepted: 28 April 2022 Published: 1 May 2022

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transition to national decarbonisation particularly relevant. The purpose of modernisation is to build such an energy system based on the intensification of clean production and the smart specialisation of regional development, which promotes the development of innovative (environmentally sustainable) technologies that significantly increase the share of renewable energy in the overall production structure. For Ukraine, given the current conditions of European integration, the focus should be on the threats and risks of energy and administrative decentralisation and mechanisms for their appropriate response in the context of the integration of the national energy system with the EU energy system. Despite the reduction in sulphur dioxide emissions in Ukraine in 2018–2020 to 20% annually, mainly due to the replacement of renewable energy production of electricity by heat generation capacity, there is still a need for further national decarbonisation of Ukraine's energy sector through environmental modernisation.

The proclamation of the new Green Deal Strategic Plan by the European Union in December 2019 [1] marked a new stage in its development, which is a significant transformation of public consciousness, and its implementation requires fundamental and ambitious goals to address pressing climate and environmental issues. Decarbonisation, minimisation of carbon emissions and transition to alternative energy sources—the central elements of the Green Deal—will be the basis for a number of fundamental transformational transitions, measures for regulatory adaptation and the introduction of protection mechanisms. As a political framework, this European agenda is a response to the challenges of global climate change, environmental pollution and, in light of its initiatives, the positioning of the European Union as a world leader.

Ukraine was chosen as the focus of the study, because after the accession of the Ukrainian energy system to the European ENTSO-E, the energy space became one, creating conditions for mutual strengthening and collective security throughout the region. In recent years, Europe has radically changed its policies regarding fossil fuels. The EU produces approximately one-third of its electricity using local renewable energy resources. The analysis of the role of energy systems in economic transformation to achieve sustainable development is a subject of research interest for European researchers [2]. Thus, the trend of the increasing share of renewable energy in the Ukrainian energy balance is promising.

The current composition of the national energy balance devotes more than half to nuclear generation; however, it is planned to gradually increase the weight of "green" energy to 25% based on the transformation of the energy balance in favour of low-carbon energy sources and the development of new energy technologies that can be used to achieve carbon neutrality. In the structure of the country's own production, the largest shares were: nuclear energy (35.1%), natural gas (27.8%), coal (22.4%) and renewable energy sources (RES) (10.3%). In the structure of total RES production in 2020, the largest share was occupied by biofuels and waste (75.4%). In the structure of electricity production, hydropower was the largest share of RES, but its share decreased by 16.3 percentage points, and, at the same time, the share of solar energy increased by 11.8 percentage points, wind energy increased by 3.3 percentage points, and biofuels increased by 1.2 percentage points [3].

The electricity market in Ukraine has a surplus, so the benefits to European consumers, namely, receiving cheaper energy than in Europe, as well as reducing dependence on Russian energy, are obvious. The stability of the Ukrainian energy system represents an additional reserve of stability for Europe.

In accordance with the strategic course enshrined in the Constitution of Ukraine to attain full membership in the EU and Ukraine's international obligations, the concept of "green" energy transition by 2050 was formed in Ukraine [4].

At the same time, the large-scale process of global support for Ukraine during the military conflict opens up prospects for its early integration into the European energy system, the transformation of its own energy market by carrying out balanced measures, and general economic integration with the EU, especially since national integration intentions coincide with European resource opportunities.

As one of the largest energy markets in Europe, Ukraine's energy market is primarily in need of integration into the European energy system and decarbonisation to ensure the country's energy security. This study highlights the existing resource and innovation trends in the greening of national and regional ecosystems, particularly in the energy sector of Ukraine's economy.

This study identifies the most relevant prerequisites and factors for greening innovation systems at the national and regional levels in the postwar reconstruction of Ukraine's economy, taking into account the latest integration changes in relations between Ukraine and the EU, as well as between Ukraine and the world. The second section is devoted to the analysis of literature sources, both for the ecological component of regional systems (Section 2.1) and for the environmental regulation of alternative energy sources (Section 2.2). Section 3 illustrates the research methodology, consisting of conceptual principles of integration and European environmental programmes (Section 3.1), the method of screening areas for the most favourable development of Ukraine's postwar economy (Section 3.2) and examples of their application (Section 3.3). The fourth section of the article is aimed at examining innovative components of the sustainable postwar development of Ukraine's economy, such as decarbonisation and "green transition" (Section 4.1), with a review of a number of global innovation indices and the analysis of regional innovation development in the country. This section also contains a study of the impact of state regulation on the process of decarbonisation/adaptation in the region (Section 4.2) and applied models of decarbonisation of energy-intensive sectors (Section 4.3). Finally, the findings include the main results of a study on achieving a carbon-neutral level in Ukraine's economy.
