Thesis specifies the essence of energy-efficiency gaps, and their types substantiate their system-forming determinants and define the basic principles of state policy for their minimization.
Thus, the energy-efficiency gap in the national economy is a discrepancy between the potential and actual levels of energy-efficiency of the national economy, due to the use of inefficient technologies of energy production, transportation and consumption, limited green investment for their renewal, asynchrony of government regulation of the energy sector in Ukraine.
The typology of approaches to the assessment of energy-efficiency gaps by an integrated combination of two criteria features – the dominant element of the assessment model and the object of comparison, is developed. A methodological tool fo estimating energy-efficiency gaps is developed. It is based on the use of stochastic frontier analysis and Shepard's energy distance function. Besides, it considers the random nature of endogenous determinants for energy-efficiency gaps and their causal relationship with the globalization levels, political economy openness, and urbanization as exogenous determinants. In Ukraine, the average level of energy-efficiency gaps during the study period was 0.12. The critical bifurcation points were in 2009 and 2015. It was explained by the impact of the global financial crisis and the escalation of military-political conflicts in the country. The growing dynamics of the level of energy efficiency gaps in Ukraine was due to the excess of the negative effect of growth in exports of primary energy resources and the use of inefficient technologies for their processing over the positive impact of imports of energy-efficient innovations.
A retrospective analysis of the dynamics of changes in the level of energy-efficiency gaps for 2002-2019 in Ukraine showed that the minimum size of energy-efficiency gaps was in 2010 and 2016 when the strategies and programs for the energy sector development were ratified.
The systematic framework to forecast by energy-efficiency gaps using Box-Jenkins methodology with autoregressive integrated modelling ARIMA is deepened. The findings allowed concluding that the foresight trend of energy-efficiency gaps was growing, and critical bifurcation points occur in 2024 and 2027. In this case, the targets of the state strategy realization for the transition to a carbon-neutral economy are substantiated, considering the identified bifurcation points.
The indices of the quality of the institutional environment in Ukraine for 2002-2019 confirmed the hypothesis that the impact of institutional determinants on the volume of energy-efficiency gap should be studied element by element, rather than integrally. The overall effect of institutional determinants on the size of energy-efficiency gaps was more than 30 % determined by the political stability of the government and more than 60 % by the level of public intolerance of corruption. It is these detriments that are the conditions for ensuring the effectiveness of the state policy of minimizing the energy-efficiency gap in Ukraine.
The co-integration ties in Ukraine in the chain "the institutional environment quality ↔ volume of attracted green investments in the energy sector ↔ volume of energyefficiency gaps" are empirically confirmed. Targets of investment and institutional determinants, the achievements of which cause annual minimization of energy-efficiency, are identified. It is established that the time lag of manifestation of the influence of the determinants of energy-efficiency gaps' minimization was one year. To reduce the volume of energy-efficiency gap by 1 % in the next year, it was necessary to increase the indices of public rejection of corruption and political stabilization of the government by 1 % and 3 %, respectively, and the volume of green investments in the energy sector – by 15 %.
While maintaining the current format of the state regulatory policy, the rate of return of the energy market of Ukraine to equilibrium on its own, without cardinal state intervention, is meagre. In order to bring this speed closer to the maximum level, it was necessary to increase the index of public rejection of corruption to 1.47 points, and the index of political stability of the government – to 2.38 points.
Keywords: carbon-neutral economy, energy security, energy-efficiency, green energy transition, national economy, energy-efficiency gaps, green investments, sustainable development.
