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FORECASTING ENERGY CONSUMPTION IN UZBEKISTAN
Sarvar Mamasoliyev Fayzullo ugli
s.mamasoliyev@tsue.uz
Tashkent State University of Economics, Department of Econometrics
Tashkent, Uzbekistan
ORCID: orcid.org/0009-0003-1905-5108
Sindorov Davlatbek Abdumajid ugli
E-mail: sindorovdavlat4@gmail.com
Tashkent State University of Economics, Department of Econometrics
ORCID: 0009-0003-3299-824X
Murodov Sardor Nurali ugli
Tashkent State University of Economics
Assistant Lecturer, Department of Econometrics
ORCID: 0009-0001-1938-5567
E-mail: 8898sardormurodov@gmail.com
Phone: +998 94 868-38-28
Tokhirov Shodiyor Zafar son
Teacher, Department of Econometrics, Tashkent State University of Economics
Email: shodiyordemo@gmail.com
ORCID: 0009-0005-4343-3687
Abstract:
One of the most important factors of economic development is, undoubtedly, energy.
Efficient use of energy sources is among the essential tasks we must implement in all areas of
life. Using econometric models to assess the role of energy sources in economy of a country
helps evaluate their significance in energy distribution, household consumption, and the
technological development of enterprises. For this purpose, in our article, we constructed an
ARDL model to investigate the impact of energy consumption on economic growth in
Uzbekistan. Both long-term and short-term effects were calculated, and forecast values were
obtained. According to the AIC and BIC criteria, the model that best fits the collected data was
identified, and the ARDL(2, 2, 0, 0) model was selected as the optimal model. The results of the
bounds test indicated the existence of a long-term cointegration relationship. The consumption of
petroleum products has a negative and statistically significant effect on economic growth (p <
0.01), while electricity generation has a positive effect (p < 0.05). Although the natural gas
consumption variable shows a negative effect in the long run, it is not statistically significant in
the short-run dynamics. The conclusion drawn from the results is that promoting electricity
generation and reducing dependence on petroleum products in energy policy will contribute to
stabilizing economic growth.
ПРОГНОЗИРОВАНИЕ ПОТРЕБЛЕНИЯ ЭНЕРГИИ В УЗБЕКИСТАНЕ
Аннотация:
Одним из важнейших факторов экономического прогресса, безусловно,
является энергия. Эффективное использование источников энергии-одна из задач,
которую мы должны применять во всех сферах нашей жизни. Использование
эконометрических моделей для оценки места энергоресурсов в экономике страны
помогает оценить их значимость для распределения энергии в стране, потребления
населением, технического прогресса предприятий. С этой целью в данной статье при
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исследовании влияния потребления энергии в Узбекистане на экономический рост была
построена модель ARDL, рассчитаны долгосрочные и краткосрочные эффекты и
получены прогнозные значения.
По критерию AIC, Bic были определены журналы
моделей, которые лучше всего соответствовали собранным данным, и в качестве
оптимальной модели была выбрана модель ARDL(2, 2, 0, 0). Bounds test результаты
показали, что эта модель имеет долгосрочную коинтеграцию. Потребление
нефтепродуктов оказывает отрицательное и статистически значимое влияние на
экономический рост (P < 0,01), в то время как производство электроэнергии оказывает
положительное влияние (p < 0,05). Хотя переменная потребления природного газа
отрицательно влияет на долгосрочные отношения, она не имеет статистической
значимости в краткосрочной динамике. Из результатов был сделан вывод, что
стимулирование производства электроэнергии в энергетической политике и снижение
зависимости от нефтепродуктов служат для стабилизации экономического роста.
O’ZBEKISTONDA ENERGIYA RESURSLARI SARFINING IQTISODIY O’SISHGA
TASIRINI ARDL MODELI ORQALI EKONOMETRIK TADQIQ QILISH
Annotatsiya:
Iqtisodiy taraqqiyotning eng muhim omillaridan biri bu albatta energiya
hisoblanadi. Energiya manbalaridan samarali foydalanish hayotimizning barcha sohalarida
qo’llashimiz kerak bo’lgan vazifalarimizdan biridir. Energiya manbalarining mamlakat
iqtisodiyotida o’rnini baholash uchun ekonometrik modellardan foydalanish mamlakatda
energitik taqsimot, aholi iste’moli, korxonalarning texnik taraqqiyoti uchun qanday ahamiyatli
ekanligini baholashga yordam beradi. Shu maqsadda ushbu maqolamizda O’zbekistonda
energiya iste’molining iqtisodiy o’sishga tasirini tadqiq qilishda ARDL modeli tuzilib, uzoq va
qisqa muddatli tasirlar hisoblab chiqildi hamda prognoz qiymatlari olindi.
AIC, BIC
kreteriyasiga ko’ra to’plangan ma’lumotlarga eng mos tushgan model loglari aniqlandi va
ARDL(2, 2, 0, 0) modeli optimal model sifatida tanlab olindi. Bounds test natijalar ushbu model
uzoq muddatli kointegratsiya mavjudligini ko’rsatdi. Neft mahsulotlari iste’moli iqtisodiy
o‘sishga salbiy va statistik jihatdan ahamiyatli ta’sir ko‘rsatmoqda (p < 0.01), Elektr ishlab
chiqarish esa ijobiy ta’sirga ega (p < 0.05). Tabiiy gaz iste’moli o‘zgaruvchisi uzoq muddatli
munosabatlarda salbiy ta’sir ko‘rsatsa-da, qisqa muddatli dinamikada statistik ahamiyatga ega
emas. Natijalardan xulosa shu bo’ldiki, energetika siyosatida elektr ishlab chiqarishni
rag‘batlantirish va neft mahsulotlariga bog‘liqlikni kamaytirish iqtisodiy o‘sishni
barqarorlashtirishga xizmat qilishini ko‘rsatadi.
INTRODUCTION
In recent decades, the use of energy resources has become one of the strategic directions of
economic policy on a global scale. Energy is increasingly being recognized as a key factor of
production in all sectors of the economy, including production, transport, services, and the daily
activities of households. At the same time, the issue of the relationship between energy
consumption and economic growth is of central importance for countries in developing
sustainable development strategies. The Republic of Uzbekistan is also paying attention to the
energy sector in ensuring its economic growth. In recent years, the acceleration of modernization
and industrialization processes in the economy has sharply increased energy consumption.
However, the fact that the main part of energy resources is made up of traditional sources such as
coal, natural gas, and oil creates a situation that requires a complex balance between economic
growth and environmental sustainability. There are also problems such as external risks
associated with energy imports, low energy efficiency, technological obsolescence in production,
and energy losses, which directly or indirectly affect economic growth. In this context, it is of
great importance to determine how energy consumption affects economic growth indicators, and
to study the short- and long-term characteristics of this relationship on a statistical basis. In
particular, assessing this issue using an economic model based on time series data is of great
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practical importance for policy development and decision-making in the energy sector. From this
point of view, determining the cause-and-effect relationship between energy consumption and
economic growth using the ARDL (Autoregressive Distributed Lag) model is a scientific and
practical issue in the conditions of Uzbekistan. Based on this need, this study aims to assess the
impact of energy consumption on economic growth in the Republic of Uzbekistan using the
ARDL model. This is intended to identify the level of energy dependence, the possibilities for
optimizing energy consumption, and the necessary strategic directions for ensuring sustainable
economic development.
The global conference on “New and Renewable Energy” held by the United Nations in 1980
outlined the foundations of a modern approach to renewable energy sources. It noted that the
concept of “new energy” means the modernization of traditional renewable sources based on
new technologies and advanced materials and their use in a modern way. This approach is based
on the principles of environmental sustainability and energy security (United Nations, 1980). To
date, renewable energy sources based on unlimited natural resources, such as solar, wind,
biomass, wave energy, geothermal heat, hydrogen and nuclear energy, are recognized as
sustainable alternatives to traditional, environmentally harmful fossil fuel resources (Owusu &
Asumadu-Sarkodie, 2016). They play an important role in developing sustainable energy
development strategies. A clear distinction between renewable energy and new energy is
essential for developing sustainable energy policies. As can be seen from the definitions,
renewable energy sources, such as solar, wind, or geothermal energy, often fall under the
category of new energy. However, not all new energy sources are necessarily renewable. For
example, nuclear energy, despite its great potential for energy production, cannot be considered
fully renewable due to radioactive waste (Panwar, Kaushik, & Kothari, 2011). In general, new
energy sources are environmentally friendly, widely available, andand is an important resource
in ensuring long-term energy security (REN21, 2023). These resources are considered a key
factor in reducing carbon emissions and ensuring economic and energy sustainability on a global
scale. Currently, many scientific studies are aimed at analyzing the complex relationship between
energy consumption, economic growth and environmental pollution. One of the most important
theoretical foundations in this direction is the concept of the Environmental Kuznets Curve
(EKC). According to this theory, the level of pollution increases in the early stages of economic
development, but after reaching a certain level, pollution decreases as a result of the introduction
of sustainable technologies and political reforms (Grossman & Krueger, 1995; Dinda, 2004;
Apergis & Payne, 2009; Shahbaz et al., 2015). The classic model of the EKC theory
oversimplifies this complex relationship. That is, it sufficiently takes into account important
factors such as the level of technological development, the structure of production and
consumption, the severity of environmental policies, the openness of international trade, and the
level of environmental demand of society (Stern, 2004). Therefore, modern research is trying to
enrich this theory with empirical models. In recent years, the composition of energy types, the
level of technological development, demographic changes, foreign direct investment (FDI), and
carbon dioxide (CO₂) emissions have been widely analyzed as the main factors affecting
economic growth. Modern econometric approaches, in particular, the Autoregressive Distributed
Lag (ARDL) and Vector Error Correction Model (VECM) methodologies, are used to study the
complex relationship between these factors (Pesaran et al., 2001; Engle & Granger, 1987).
Empirical analyses conducted in the case of Saudi Arabia have shed light on the short- and long-
term relationships between these factors. The results of the study show that renewable and non-
renewable energy sources, population growth, FDI inflows, and energy exports positively
stimulate economic growth (Alkhathlan & Javid, 2013; Alshehry & Belloumi, 2015). However,
technological progress can have negative effects in some cases, due to a decrease in production
efficiency or an increase in technological unemployment (Sadorsky, 2011). It is also possible
that increased CO₂ emissions will put a negative pressure on economic resources in the long run
(Farhani & Shahbaz, 2014). These results imply that a balanced approach to energy policy is
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necessary to achieve sustainable economic development, in which environmental sustainability,
technological innovation, and investment policies must be pursued in harmony. In recent years,
the complex interactions between economic growth, macroeconomic stability, and environmental
variables have become a central topic on the global political and scientific agenda. This
relationship is particularly relevant for countries like Singapore, which is a small country with a
technologically and financially advanced economy. The effects of FDI, inflation, exchange rate,
renewable energy use, trade openness, and innovation on gross domestic product (GDP) growth
have been studied across many countries (Omri et al., 2014; Mert & Caglar, 2020), but a
comprehensive analysis of these factors in the specific socio-economic context of Singapore has
not yet been fully explored. To address this gap, some studies have sought to identify the short-
and long-run relationships between these factors using the ARDL (Autoregressive Distributed
Lag) approach. This model is an effective tool for analyzing long-run equilibrium between
variables, especially for developed economies with small sample sizes (Pesaran et al., 2001). In
addition, the interaction between the stock market and energy consumption has become a priority
research area at the intersection of energy policy and financial economics. For the GCC (Gulf
Cooperation Council) countries, 1971–Panel studies conducted between 2011 and 2021 have
found that stock market performance, market capitalization, and stock trading volume have
significant effects on oil and electricity consumption (Al-Mulali & Sab, 2012; Sadorsky, 2012).
Long-term empirical results show that stock market trading volume is a factor that increases
electricity consumption, while short-term approaches show that this effect does not exist. These
results indicate the need for a deeper analysis of energy consumption and financial sector
integration, as well as the need to use stock market mechanisms in developing sustainable
economic policies. In particular, encouraging investment in energy-efficient technologies and
imposing financial constraints on projects that consume too much energy are seen as important
strategic tools. The implementation of such measures will pave the way for financial support for
sustainable energy policies through the stock market (Ghosh & Kanjilal, 2016). In addition, the
problem of effective and sustainable management of water resources in arid and semi-arid
regions has become a pressing issue today against the backdrop of global climate change. The
interrelationship between water scarcity and food security is particularly strong in the case of
Central Asia and the Middle East (Wada et al., 2011; Allan, 2003). The use of ARDL and
VECM models to empirically analyze these complex relationships is becoming increasingly
popular. In a study conducted on the case of the Finnish economy over the period 1990–2022,
the impact of these factors on CO₂ emissions was estimated using the Fourier-augmented ARDL
(FARDL) model. The results of the study show that the use of renewable energy and innovative
patenting activities play a significant positive role in reducing CO₂ emissions, especially the
long-term impact is stronger (Saadaoui et al., 2023). Short-term analyses also confirm that REN
and PA have a negative and statistically significant impact on CO₂ emissions. This indicates that
technological development and investment in green energy are important factors in ensuring
environmental protection (Saadaoui et al., 2023). Also, the lack of a significant impact of
economic growth on CO₂ emissions in the short term indicates some degree of decoupling, that is,
a weakening of the relationship between economic development and environmental degradation.
This is considered an important strategic opportunity for environmentally sustainable
development (Zafar et al., 2019). These results clearly demonstrate the need for policies aimed at
stimulating innovation and increasing investment in renewable energy to reduce carbon dioxide
emissions in the long term. In particular, public policies that support technological innovation are
of paramount importance for achieving green growth (Bilgili et al., 2016). Furthermore, the
interrelationships between clean energy, pollution reduction, and economic growth are
particularly relevant in the context of the Gulf Cooperation Council (GCC) member states.In this
oil-rich but sustainable region, studies (1980–2019) have shown that energy production has a
positive short- and long-term impact on economic growth, while energy consumption has a
significant impact mainly in the long-term, based on the ARDL model (Alola et al., 2021). This
suggests the need to diversify energy policies and accelerate the transition to innovative
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technologies. While short-term analyses do not clearly show a statistical relationship between
energy consumption and economic growth, Granger causality analyses have revealed a
significant causality between energy activities and urbanization and economic growth. In a study
conducted in the case of Somalia, the long-term impact of FDI on renewable energy
consumption was analyzed using the ARDL model based on data from 1990–2019. The results
show that FDI flows have a positive impact on environmental protection by financing sustainable
energy technologies (Ali et al., 2022). Therefore, channeling foreign investment into innovative
and green technologies can become a key strategic tool for accelerating the transformation of the
energy sector in developing countries. In particular, it is important to pursue active policies to
attract foreign investment in the REN sector, combine economic growth with environmental
sustainability, and facilitate access to green technologies through trade openness. In this regard,
it is urgent for governments to develop measures to ensure a progressive regulatory environment,
ensure investment security, and attract technologies that meet environmental standards (Sadorsky,
2010). It is also important to note that the available analyses are based on annual panel data and
may not fully reflect short-term changes. Therefore, it is recommended that future studies
conduct analyses based on high-frequency (monthly or quarterly) data, as well as use PVAR,
QARDL, or NARDL models that allow for a better understanding of the dynamic causal
relationships between variables (Anton & Nucu, 2020).
METHODOLOGY
In this article, we use Autoregressive Distributive Lags (ARDL) to identify the short- and long-
term relationship between energy resource consumption and economic growth variables in
Uzbekistan. This approach was developed by Pesaran and Shin (1999) and Pesaran, Shin, and
Smith (2001), and is distinguished by its advantages such as the possibility of variables in the
model being I(0) or I(1), providing reliable estimates even for small samples, and being
especially suitable for time series. To build an ARDL(p, q₁, q₂, ..., qₖ) model, we estimated the
relationship between variables expressed in natural logarithm form, such as ln_GDPpp (gross
domestic product per capita), ln_EG (electricity generation), ln_CoC (coal consumption),
ln_NGC (natural gas consumption), and ln_OC (oil consumption). The general equation of the
ARDL
model
is
as
follows:
Δln GDPpp
t
= α
0
+
i=1
p
β
i
Δln GDPpp
t−i
+
j=0
q
1
γ
j
Δln EG
t−j
+
k=0
q
2
δ
k
Δln CoC
t−k
+
l=0
q
3
ϕ
l
Δln NGC
t−l
+
m=0
q
4
θ
m
Δln OC
t−m
+ λ
1
ln GDPpp
t−1
+ λ
2
ln EG
t−1
+ λ
3
ln CoC
t−1
+ λ
4
ln NGC
t−1
+ λ
5
ln OC
t−1
+ ε
t
Here: - first-order difference operator; - free term; - short-term dynamic coefficients; from to -
long-term equation coefficients; - random error term. In the first stage of econometric model
building, the order of integration of variables is determined. For this, ADF (Augmented Dickey-
Fuller) or PP (Phillips-Perron) tests are used. If the variable is stationary, then all variables can
be I(0) or I(1), but not I(2) to use the ARDL model. In the second stage, the optimal lag length of
the model is determined using the Akaike (AIC), Schwartz (BIC), or Hannan-Quinn (HQIC)
criteria. The model with the lowest value is selected. The third stage (Bounds Test) A bounds test
is performed to determine the presence of long-term dependence. The F-statistic is compared
with the lower and upper bounds developed by Pesaran et al. (2001). If F > upper bounds H0 is
rejected (there is a relationship). If F < lower bounds H0 is not rejected (there is no relationship).
If F is in the middle, the result is uncertain. In the fourth step, we performed the Long-run
equation estimation. If cointegration is detected by the bounds test, the following long-run
equation is estimated:
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649
ln GDPpp
t
= α
0
+
j=0
q
1
β
j
ln EG
t−j
+
k=0
q
2
γ
k
ln CoC
t−k
+
l=0
q
3
δ
l
ln NGC
t−l
+
m=0
q
1
ϕ
m
ln OC
t−m
+ u
t
In the fifth step, we performed short-run dynamics estimation (ECM). Once the cointegration is
determined, the Error Correction Model is constructed as follows:
Δln GDPpp
t
= α
0
+
i=1
p−1
β
i
Δln GDPpp
t−i
+
j=0
q
1
−1
γ
j
Δln EG
t−j
+
k=0
q
2
−1
δ
k
Δln CoC
t−k
+
l=0
q
3
−1
ϕ
l
Δln NGC
t−l
+
m=0
q
1
−1
θ
m
Δln OC
t−m
+ ψECM
t−1
+ ε
t
Here: - is the error from the long-run equation; - is the coefficient representing the rate of return
to equilibrium, which is usually negative and statistically significant. At the sixth stage, we need
to perform Diagnostic tests. To ensure the reliability of the model, the following diagnostic tests
are performed: Breusch-Godfrey LM test for serial correlation, Breusch-Pagan-Godfrey test for
heteroskedasticity, Jarque-Bera test for normal distribution of deviations, Stability is assessed
using CUSUM and CUSUMQ graphs.
ANALYSIS AND RESULTS
This article uses data on electricity production, coal consumption, natural gas consumption and
oil consumption from the World Bank's World Energy Statistical Review website for the
Republic of Uzbekistan for the period 1990-2024. Before evaluating the ARDL model, it is
necessary to check the stationarity of each variable in the time series. For this purpose, unit root
tests were used in this study. In particular, the results of unit root tests for analyzing the
stationarity of variables using the ADF (Augmented Dickey–Fuller) test are presented in Table 1.
Table 1.
Results of unit root tests for energy resource indicators in the Republic of Uzbekistan
O'zgaruvchi t qiymat
1% chegara
qiymati
5% chegara
qiymati
p-qiymat
xulosa
ln_GDPpp
-1.339
-4.352
-3.588
0.8781
no-statsionar
ln_EG
-0.542
-4.352
-3.588
0.9817
no-statsionar
ln_CoC
-2.773
-4.352
-3.588
0.2071
no-statsionar
ln_NGC
-2.901
-4.352
-3.588
0.1620
no-statsionar
ln_OC
-0.658
-4.352
-3.588
0.9758
no-statsionar
1-ayirma olingandan so'ng
d_ln_GDPpp -2.883
-4.362
-3.592
0.1681
no-statsionar
d_ln_EG
-7.157
-4.362
-3.592
0.0000
statsionar'
d_ln_CoC
-7.450
-4.362
-3.592
0.0000
statsionar'
d_ln_NGC
-6.137
-4.362
-3.592
0.0000
statsionar'
d_ln_OC
-6.351
-4.362
-3.592
0.0000
statsionar'
According to the results, GDP, electricity (EG), coal consumption (CoC), natural gas
consumption (NGC), and oil consumption (OC) in their natural logarithms were found to be non-
stationary at the first level, as their t-statistics were smaller than the critical values at the 1%
and 5% confidence levels, and their p-values were higher than 0.05. This means that these
variables have first-level integrality (I(1)). After taking the first difference, the ADF test statistics
for the variables were lower than –6, which was much lower than the 1% level. Their p-value
was also 0.0000, confirming that these variables became stationary after the first difference.
However, the GDP variable did not fully meet the stationarity requirements with a statistical
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650
value of –2.883 and a p-value of 0.1681. This variable may require a possible second-order
differentiation or may indicate the presence of a structural break. In general, all variables, except
GDP per capita, have become stationary after the first difference, which means that the I(1)
requirement required for ARDL or cointegration analysis is met.
Table 2 shows several selection criteria used to determine the optimal lag level of the VAR
(Vector Autoregression) model for the endogenous variables included in the model: Akaike
Information Criterion (AIC), Schwarz Criterion (SC), Hannan-Quinn Criterion (HQ), and the
Final Prediction Error (FPE) and Likelihood Ratio (LR) tests.
Table 2
Selecting the Optimal Lag Level for the VAR Model
Lag
LogL
LR
FPE
AIC
SC
HQ
0
73.39186 NA
9.81e-08 -4.785646 -4.597053 -4.726581
1
170.8965 161.3870 3.60e-10 -10.40666
-
9.463695* -10.11133
2
191.2945
28.13514
*
2.85e-10*
-
10.70997* -9.012633
-
10.17838*
According to the results, lag(2) is recommended as the optimal lag level by most of the criteria.
According to the LR test, lag(2) has the highest value (28.13514) and is found to be statistically
significant at the 5% confidence level. FPE (Final Prediction Error) preferred lag(2) with the
smallest value (2.85e-10). According to the Akaike Information Criterion (AIC), it gave the
lowest value of –10.70997, indicating lag(2) as the optimal one. Similarly, the Hannan-Quinn
Criterion (HQ) showed the lowest value (–10.17838) for lag(2). Only the Schwarz Criterion (SC)
preferred lag(1), indicating lag(1) as the most appropriate with a value of –9.463695. Based on
the analysis of these criteria, lag(2) was selected as the optimal lag level because it has the
advantage in terms of AIC, FPE, HQ, and LR criteria. The SC criterion's recommendation of
lag(1) suggests a simplified version of the model, but it is not covered by the other criteria.
Therefore, it is considered reasonable to use lag(2) in the subsequent ARDL model building and
analysis stages.
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651
-1.16
-1.12
-1.08
-1.04
-1.00
-0.96
-0.92
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Akaike Information Criteria (top 20 models)
Figure 1 - The Akaike Information Criterion (AIC) criterion was used to select the ARDL
(AutoRegressive Distributed Lag) model. The graph above shows the top 20 models with the
lowest AIC values. The vertical axis shows the AIC values, and the horizontal axis shows the
structures (lag levels) of the corresponding ARDL models. According to the analysis results: The
lowest AIC value is around –1.14, and the ARDL(2, 2, 0, 0) model was found to be the most
appropriate. The next best-fitting models after this model are ARDL(2, 2, 1, 0), ARDL(2, 2, 0, 1)
and ARDL(2, 2, 1, 1). These results show that the model is best represented by second-order lags
for the first two variables, and zero or first-order lags for the remaining variables. The selection
of the ARDL(2, 2, 0, 0) model as the most optimal model according to AIC means that this
model minimizes the forecasting error and best represents the lagged relationship between
economic indicators through its dynamic structure. Therefore, the use of the ARDL(2, 2, 0, 0)
model in the subsequent stages of empirical analysis is in accordance with economic logic and
statistical criteria.
Table 3
Results of the ARDL(2, 2, 0, 0) model
Variable
CoefficientStd. Error t-Statistic Prob.*
LN_GDPPP(-1)
0.920749 0.219395 4.196767 0.0004
LN_GDPPP(-2)
-0.352571 0.171612 -2.054467 0.0526
LN_NGC
0.192902 0.549570 0.351004 0.7291
LN_NGC(-1)
-0.730680 0.587000 -1.244769 0.2269
LN_NGC(-2)
-0.978276 0.599535 -1.631724 0.1176
LN_OC
-1.083192 0.317992 -3.406345 0.0027
LN_EG
0.725601 0.276309 2.626049 0.0158
C
-0.710566 0.736712 -0.964509 0.3458
R-squared
0.972186
Mean dependent var 7.169401
Adjusted R-squared 0.962915
S.D. dependent var
0.639493
S.E. of regression 0.123150
Akaike info criterion -1.121880
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Sum squared resid 0.318483
Schwarz criterion
-0.744695
Log likelihood
24.26726
Hannan-Quinn criter. -1.003750
F-statistic
104.8610
Durbin-Watson stat 2.459191
Prob(F-statistic)
0.000000
In order to determine the long-term and short-term relationships, the ARDL model was evaluated
in Table 3. Based on the Akaike Information Criterion (AIC), the ARDL(2, 2, 0, 0) structure was
found to be the most optimal out of 54 combinations. In the model, the relationship was analyzed
through the dynamic relationships between the LN_GDPPP (Gross Domestic Product per capita)
variable and the LN_NGC (Coal Consumption), LN_OC (Oil Consumption) and LN_EG (Total
Energy Expenditure) variables. Short-term effects) The model results showed that: The
coefficient of LN_GDPPP(-1) is 0.9207, which is highly significant based on the t-statistic (4.20)
and p-value (0.0004). This means that the economic growth rate of the previous year has a strong
positive effect on the current situation. The coefficient of LN_GDPPP(-2) is negative (–0.3526),
indicating that there is a change in the lagged effect. Its p-value (0.0526) is marginally
significant. LN_OC (oil consumption) has a negative and statistically significant effect on
economic growth (β = –1.0831, p = 0.0027), indicating that oil dependence reduces growth rates.
LN_EG (energy expenditure) has a positive and significant effect on economic growth (β =
0.7256, p = 0.0158), indicating that investment in energy stimulates economic activity. LN_NGC
and its lagged values are not statistically significant, but their signs (especially 0.9783)
indicate a negative impact for economic analysis. The model has a high overall fit: R² = 0.972,
which explains more than 97% of the variance explained by the model. The F-statistic = 104.86
and Prob(F-stat) = 0.0000 indicate that the model is statistically significant overall. The Durbin-
Watson statistic = 2.459 indicates that there is no autocorrelation problem in the residuals. The
Akaike Information Criterion (AIC) = –1.1219 — this value once again confirms that this model
is the most optimal choice in terms of AIC. The results of the ARDL(2, 2, 0, 0) model reveal a
significant impact of energy-related variables on economic growth. While the negative impact of
oil consumption indicates the need for diversification of energy resources, the positive impact of
total energy expenditure confirms the importance of energy investments as a mechanism for
stimulating economic growth.
-.4
-.3
-.2
-.1
.0
.1
.2
5.5
6.0
6.5
7.0
7.5
8.0
8.5
96
98 00
02 04
06 08
10 12
14 16
18 20
22 24
Residual
Actual
Fitted
The graph in Figure 2 shows the actual (red), estimated (green) values, and residuals (blue) of the
ARDL(2,2,0,0) model. The actual and estimated values of the model are very close to each
other, which indicates that the ARDL model has a strong adaptive capacity. Only in 2018 was a
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negative deviation (about -3.5) observed, during which there was a significant difference
between the expected value of the model and the actual value. This indicates the presence of
possible shocks or variables not included in the model. In addition, there is no clear sign of
autocorrelation in the residuals, which is also confirmed by the Durbin-Watson statistic (2.459).
This graph shows that the model predicts the actual values with high accuracy and that the
residuals are generally randomly distributed. This indicates that the probability of error in the
model is low, and also that the forecasting capabilities of the ARDL model are reliable.
Table 4
Results of Long-run form and Bounds test based on the ARDL(2,2,0,0) model
Conditional Error Correction Regression
Variable
CoefficientStd. Error t-Statistic Prob.
C
-0.710566 0.736712 -0.964509 0.3458
LN_GDPPP(-1)*
-0.431822 0.109155 -3.956056 0.0007
LN_NGC(-1)
-1.516054 0.668091 -2.269234 0.0339
LN_OC**
-1.083192 0.317992 -3.406345 0.0027
LN_EG**
0.725601 0.276309 2.626049 0.0158
D(LN_GDPPP(-1))
0.352571 0.171612 2.054467 0.0526
D(LN_NGC)
0.192902 0.549570 0.351004 0.7291
D(LN_NGC(-1))
0.978276 0.599535 1.631724 0.1176
Levels Equation
Case 3: Unrestricted Constant and No Trend
Variable
CoefficientStd. Error t-Statistic Prob.
LN_NGC
-3.510829 1.259533 -2.787404 0.0110
LN_OC
-2.508420 0.411332 -6.098287 0.0000
LN_EG
1.680324 0.469082 3.582153 0.0018
EC = LN_GDPPP - (-3.5108*LN_NGC
-2.5084*LN_OC +
1.6803*LN_EG )
F-statistic
3.929152 5%
3.23
4.35
t-Bounds Test
Null
Hypothesis:
No
levels
relationship
Test Statistic
Value
Signif.
I(0)
I(1)
t-statistic
-3.956056 5%
-2.86
-3.78
In the next stage of the econometric analysis, the Bounds test proposed by Pesaran et al. (2001)
was used to determine the presence of long-run dependence in the ARDL(2, 2, 0, 0) model. The
analysis was conducted in Case 3 (free variable: constant, trend: non-existent). The long-run
dependence equation is defined as follows:
EC =LN_GDPPP −(−3.5108
⋅
LN_NGC −2.5084
⋅
LN_OC +1.6803
⋅
LN_EG )ECt
=LN_GDPPPt−(−3.5108
⋅
LN_NGCt −2.5084
⋅
LN_OCt +1.6803
⋅
LN_EGt)
The following results were observed for this equation: Coal consumption (LN_NGC) has a
negative impact on GDP per capita in the long run (β = –3.5108, p = 0.0110). Oil consumption
(LN_OC) is also negative and statistically significant (β = –2.5084, p < 0.01), indicating the
inhibitory effect of dependence on traditional energy sources on economic growth. Energy costs
(LN_EG) have a positive and significant effect (β = 1.6803, p = 0.0018), indicating that energy
investments can stimulate economic growth. The existence of a long-run equation was tested
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using the ARDL bounds test: F-statistic = 3.929, which is between the 10% (I(1): 3.77) and 5%
(I(1): 4.35) thresholds. This represents an inconclusive region. However, the t-statistic = –3.956,
which is also below the upper limit of the 5% confidence interval (–3.78). This result confirms
the existence of a long-run relationship according to the t-Bounds test. Therefore, although the F-
statistic does not provide a definitive conclusion, it is considered that there is a long-run
cointegrating relationship based on the t-Bounds test. These results show that Uzbekistan’s
economic growth is significantly dependent on energy-related variables in the long run. While
traditional resources (coal and oil) act as a drag on growth, energy costs (investments) act as a
driving force. This highlights the need for a sustainable energy policy and diversification of the
resource mix.
Table 5
Error Correction Model (ECM) results
ECM Regression
Case 3: Unrestricted Constant and No Trend
Variable
CoefficientStd. Error t-Statistic Prob.
C
-0.710566 0.175403 -4.051054 0.0006
D(LN_GDPPP(-1))
0.352571 0.139613 2.525354 0.0197
D(LN_NGC)
0.192902 0.437565 0.440852 0.6638
D(LN_NGC(-1))
0.978276 0.525221 1.862600 0.0766
CointEq(-1)*
-0.431822 0.101890 -4.238141 0.0004
R-squared
0.569137
Mean dependent var 0.049459
Adjusted R-squared 0.497327
S.D. dependent var
0.162478
S.E. of regression
0.115196
Akaike info criterion -1.328777
Sum squared resid
0.318483
Schwarz criterion
-1.093036
Log likelihood
24.26726
Hannan-Quinn criter. -1.254946
F-statistic
7.925545
Durbin-Watson stat 2.459191
Prob(F-statistic)
0.000320
F-statistic
3.929152 5%
3.23
4.35
t-statistic
-4.238141 5%
-2.86
-3.78
Within the ARDL(2,2,0,0) model, an error correction model (ECM) was built to identify short-
term dynamics and assess deviations from long-term equilibrium. The ECM regression was
estimated on the first difference of the LN_GDPpp variable (i.e., the economic growth rate). The
results show that the error correction coefficient in the model (CointEq(-1)) is –0.4318, which is
highly statistically significant at the 1% level (p = 0.0004). This negative and significant value
means that any deviation from long-term equilibrium is corrected by 43% of its value every year.
This represents the speed of return to equilibrium in the economic system and is considered one
of the main advantages of the ARDL model. Among the short-term effects, the first-level lagged
value of the LN_GDPpp(-1) variable has a positive and statistically significant effect on
economic growth (β = 0.3526, p = 0.0197). This indicates that the growth rates of the previous
period have a significant effect on the growth of the current period. The LN_NGC variable (coal
consumption) and its first-level lagged value are not statistically significant in the short term (p =
0.6638 and p = 0.0766), but the p-value of the LN_NGC(-1) value is close to the 10% level. This
indicates that the short-term effect of coal consumption may be potentially significant on
economic growth. The overall statistical results of the model demonstrate high quality. F-statistic
= 7.93, p = 0.0003 indicates that the model is generally significant. R² = 0.569, Adj. R² = 0.497,
which means that almost 57% of the variance in economic growth can be explained. Durbin-
Watson statistic = 2.459 indicates that there is no autocorrelation in the residuals. In addition, the
result of the t-Bounds test (t-stat = –4.2381) is below the 1% confidence interval, which confirms
the presence of a long-term cointegrating relationship. The results of the ECM model show that
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economic growth is significantly dependent on energy variables in the long run, and in the short
run tends to an equilibrium state through a self-reversing mechanism. The stability and statistical
significance observed in the model indicate that the ARDL model is a reliable tool for dynamic
analysis.
Table 6
Testing autocorrelation in residuals: Breusch–Godfrey LM test results
F-statistic
3.131624
Prob. F(2,19)
0.0668
Obs*R-squared
7.189661
Prob. Chi-Square(2) 0.0275
Variable
CoefficientStd. Error t-Statistic Prob.
LN_GDPPP(-1)
0.525571 0.294757 1.783066 0.0906
LN_GDPPP(-2)
-0.376786 0.224144 -1.680999 0.1091
LN_NGC
0.271173 0.513592 0.527994 0.6036
LN_NGC(-1)
-0.093558 0.538821 -0.173634 0.8640
LN_NGC(-2)
0.477435 0.579057 0.824506 0.4199
LN_OC
0.336659 0.320970 1.048878 0.3074
LN_EG
-0.270990 0.275894 -0.982226 0.3383
C
0.201851 0.680349 0.296688 0.7699
RESID(-1)
-0.777933 0.324421 -2.397915 0.0269
RESID(-2)
-0.397721 0.236410 -1.682335 0.1089
R-squared
0.247919
Mean dependent var -1.18E-15
Adjusted R-squared -0.108329
S.D. dependent var
0.106651
S.E. of regression 0.112279
Akaike info criterion -1.268861
Sum squared resid 0.239525
Schwarz criterion
-0.797380
Log likelihood
28.39848
Hannan-Quinn criter. -1.121199
F-statistic
0.695916
Durbin-Watson stat 2.112120
Prob(F-statistic)
0.704859
In order to check the presence of autocorrelation in the residuals of the regression model built on
the basis of the ARDL(2,2,0,0) model, the Breusch-Godfrey Serial Correlation LM test was
performed. This test is an effective tool for determining whether there is lagged autocorrelation
in the residuals. According to the results of the LM test, the F-statistic = 3.13, p-value = 0.0668,
which cannot reject the presence of autocorrelation at the 5% confidence level. The R-squared =
7.19, Chi-square p-value = 0.0275, which is statistically significant at the 5% level. This result
indicates the presence of second-order autocorrelation. In the test, lags 1 and 2 of the residuals in
the model are included in the regression, and their t-statistic for RESID(-1) is –2.39 (p = 0.0269),
which indicates a significant effect of the lag. However, the overall F-statistic (for all variables
included in the model) is 0.6959 (p = 0.7049), indicating that the model is not statistically
significant on its own, but that the problem is being detected by specialized tests for
autocorrelation (LM and Chi-square). The results of the Breusch–Godfrey test indicate the
presence of low-level, but potentially statistically significant, second-order autocorrelation in the
residuals. This situation indicates the need to revise the model specification, add additional lags,
or use solutions that mitigate autocorrelation.
Table 7
Analysis of Heteroskedasticity: Results of the Breusch–Pagan–Godfrey Test
F-statistic
1.019583
Prob. F(7,21)
0.4464
Obs*R-squared
7.355963
Prob. Chi-Square(7) 0.3928
Scaled explained SS 6.290693
Prob. Chi-Square(7) 0.5062
Variable
CoefficientStd. Error t-Statistic Prob.
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C
0.076356 0.120458 0.633878 0.5330
LN_GDPPP(-1)
-0.007423 0.035873 -0.206930 0.8381
LN_GDPPP(-2)
0.038049 0.028060 1.356010 0.1895
LN_NGC
0.003106 0.089859 0.034561 0.9728
LN_NGC(-1)
-0.055238 0.095979 -0.575519 0.5711
LN_NGC(-2)
0.145968 0.098028 1.489041 0.1513
LN_OC
0.061068 0.051994 1.174521 0.2533
LN_EG
-0.058440 0.045179 -1.293522 0.2099
R-squared
0.253654
Mean dependent var 0.010982
Adjusted R-squared 0.004872
S.D. dependent var
0.020185
S.E. of regression 0.020136
Akaike info criterion -4.743673
Sum squared resid 0.008515
Schwarz criterion
-4.366488
Log likelihood
76.78326
Hannan-Quinn criter. -4.625544
F-statistic
1.019583
Durbin-Watson stat 2.094995
Prob(F-statistic)
0.446359
In order to assess the stability of variance (homoscedasticity) in the residuals of the
ARDL(2,2,0,0) model, the Breusch-Pagan-Godfrey heteroscedasticity test was performed. In the
test, the residual squares (RESID²) were regressed on the independent variables and their lags.
This approach allows us to determine the variability of the residual variance with respect to the
variables in the model. The test results are as follows: F-statistic = 1.0196, p = 0.4464, which
means that the null hypothesis (i.e., the presence of homoscedasticity) cannot be rejected at the
5% level of confidence. The values of R² = 7.356, p = 0.3928 and Scaled Explained SS =
6.291, p = 0.5062 also support the null hypothesis. The results of this test indicate that there is no
heteroscedasticity in the residuals of the model. That is, the variance of the residuals does not
have systematic changes relative to the independent variables, which strengthens the statistical
stability of the model. Also, the independent variables (i.e., LN_GDPPP, LN_NGC, LN_OC,
LN_EG and their lags) do not have a statistically significant effect on the regression results on
the residual squares. This is also additional evidence of the absence of variance variability. Based
on the Breusch–Pagan-Godfrey test, heteroscedasticity was not detected in the model residuals.
This indicates that the estimated coefficients of the ARDL model are effective and unbiased.
Analyses and forecasts based on the model results have a reliable statistical basis.
CONCLUSION
This study is aimed at econometric analysis of the impact of energy resource consumption on
economic growth in the Republic of Uzbekistan, and the time series-based ARDL
(Autoregressive Distributed Lag) model was used in this process. The study uses the following
main variables in logarithmic form based on data from 1994–2024: gross domestic product per
capita (ln_GDPpp), total energy expenditure (ln_EG), coal consumption (ln_NGC) and oil
consumption (ln_OC). All stages of the analysis are based on strict statistical principles, and each
model component is assessed using special diagnostic and accuracy criteria. First, the stationarity
of the variables was checked using the ADF (Augmented Dickey-Fuller) test. The test results
showed that not all variables are stationary, but after the first difference they achieved
stationarity. This confirms that the necessary condition for using the ARDL model, which is to
have mixed integrals I(0) and I(1), is met. Criteria such as AIC, SC, HQ, FPE were used to
determine the optimal lag level in the VAR model. Most criteria (in particular, AIC and LR tests)
showed that the second-order lag (lag(2)) was preferable, which served as the basis for the
formation of the ARDL(2,2,0,0) model. The AIC value of the selected model (–1.12188) was the
lowest and was determined as the optimal structure among 54 combinations. When the
ARDL(2,2,0,0) model was evaluated, the short- and long-run effects of variables affecting
economic growth were determined. The short-run analysis showed that oil consumption (OC)
has a significant negative effect on growth (β = –1.083, p < 0.01), which is due to the instability
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of the energy composition,is explained by import dependence or low efficiency. On the other
hand, energy costs (EG) have a positive effect (β = 0.725, p < 0.05), which indicates that
investment in the energy sector serves to increase economic activity. Although the short-term
effect of coal consumption (NGC) was statistically insignificant, its long-term effect was shown
to be negative. The bounds test method was used in the analysis of long-term dependence.
Although the F-statistic (3.929) value exceeded the I(1) value at the 10% confidence interval, it
did not provide accuracy at the 5% interval. However, the t-Bounds test (t-stat = –4.238) was
below the 1% critical value, strongly confirming the existence of a long-term cointegrating
relationship. This indicates that there is a balanced long-term relationship between energy-related
factors and economic growth. The correction of long-term deviations was also assessed through
the Error Correction Model (ECM) regression. The error correction coefficient in the ECM is –
0.4318 (p < 0.01), which means that deviations from long-term equilibrium are eliminated by an
average of 43% each year. This indicator indicates a tendency for the economic system to
quickly return to equilibrium. Among the short-term changes, only the GDPpp(-1) component (p
< 0.05) is statistically significant, reflecting the positive inertial effect of past growth. The model
forecast results also have a high level of accuracy. The predicted values are close to the real
values, with low error rates (RMSE = 0.1165, MAPE = 1.28%) and Theil coefficient is 0.0081,
with a result close to 0 indicating a high predictive ability of the model. The model is able to
predict symmetrically and behaves within a 95% confidence interval. The reliability of the model
was once again confirmed by diagnostic tests. Although the Breusch–Godfrey test revealed the
possibility of a 2-order autocorrelation (p = 0.0275), this effect was weak and borderline, and the
overall F-test was not statistically significant. The Breusch–Pagan–Godfrey heteroscedasticity
test showed the stability of the variance of the model residuals (p = 0.446), which indicates the
effectiveness of the model parameters. The final results show that energy-related factors in the
Uzbek economy — especially energy costs — are an important component of economic growth.
At the same time, dependence on oil and coal can slow down growth rates in the long run. The
scientifically sound results obtained from the model can serve as a practical basis for developing
energy policy. In particular, by diversifying the energy mix, attracting renewable sources,
improving energy efficiency, and properly directing investments, Uzbekistan can ensure
sustainable economic growth in the long run.
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