This paper uses empirical evidence to examine the causality relationship between electricity consumption and economic growth in OPEC countries by using annual data (1980–2011); this paper also utilises the panel cointegration and panel-based error correction approach models and framework. To the best of the authors' knowledge, most of the studies in this field have applied the error correction models, auto regressive distributed lag and panel data based on fixed-effect model in which coefficients obtained by these models cannot be deemed as a general finding applicable for other countries. The superiority of our article is in applying full modified ordinary least square estimation method for heterogeneous panels; our study also has stable and consistent coefficients and is also a dynamic model. Moreover, with regard to previous studies, our paper includes more countries which increase the reliability of the results. The results indicate that a long-run relationship exists between real gross domestic product (GDP), electricity consumption and trade activities that involve export and import (control variable). The short-run results also indicate the importance of electricity consumption to economic growth and vice versa, supporting the feedback hypothesis which asserts that energy policies oriented towards improvements in electricity consumption efficiency would not adversely affect real GDP. It also apears that policies for energy efficiency have no statistically significant impact on economic growth in long run.

This study explores the long-run impact of idiosyncratic and common shocks on industry output in Ghana while controlling for the effects of investment. In order to deal with the second-order bias problem, this study employed canonical cointegration and fully modified ordinary least-squares (OLS) regressions, which are more robust to second-order bias problems. Different models are, therefore, specified and estimated. Fully modified OLS and canonical cointegration are extended in successive steps in order to verify if the inclusion of idiosyncratic and common shocks improves the statistical properties of the model. Secondly, a backward approach, in which idiosyncratic and common shocks are excluded successively, is also adopted. Preliminary findings showed signs of long-run equilibrium. The a priori expectation and the statistical importance of investment are established in both fully modified OLS and canonical cointegration models. This result is robust using both the Bartlett and Parzen kernels. However, while the elasticity value for investment is invariant to the model and kernel type used for fully modified OLS, the opposite result is found for canonical cointegration. Importantly, the absolute value of the investment elasticity is kept within the limits of 0 and 1. The impacts of idiosyncratic and common shocks are negative and statistically significant in the long run for both fully-modified OLS and canonical cointegration. This result is robust to the Bartlett and Parzen kernels. Result based on the fully modified OLS also showed that the sizes of the elasticity values for both idiosyncratic and common shocks are sensitive to the model type and kernel type used. Despite the differences in the elasticity values, result for both models are qualitatively similar.

This study examines the general relationships between crude oil consumption, real oil price and real GDP using a quarterly time series from 1993 to 2012. Specifically, the long-term and short-term GDP and price elasticities of oil consumption per capita were estimated using dynamic panel and pooled data regressions based on Nerlove's oil demand model for 25 countries that represent 75 per cent of global oil demand. Price elasticities were found for most OECD countries. These estimates were low and consistent with previous estimates. According to the study results, the short-run price elasticity ranged between −0.05 and −0.20 and the long-run between −0.11 and −0.36. Price elasticities for most non-OECD countries were either positive or insignificant. Estimates of GDP elasticities varied. The short-run GDP elasticity was between 0.15 and 1.09, while the long-run was between 0.21 and 1.54. On average, income elasticity for OECD countries was found to be slightly higher than for non-OECD countries. Contrary to expectations, we found China's income elasticity to be 0.34 in the short run, but it was 0.76 in the long run.

Period-wise energy coefficients for members of the Organization of the Petroleum Exporting Countries (OPEC) were calculated, showing diverse behaviour among them. Behaviour of aggregate OPEC coefficients reflects the general trend among its member nations. Acceleration of transportation fuel demand fuelled high intensities in the mid-1970s. An overall economic downturn in the 1980s did not dampen demand growth, but in fact accelerated in the industrial and household, public and commercial (HPC) sectors, thus keeping energy coefficients above 1. Energy coefficients were headed towards unity in the 1990s, before finally settling under 1 in the 2000s. We caution from interpreting these developments as improvements in efficiency, as OPEC member countries have not become ‘post-industrial’ as more value-added industries, infrastructure development and stability encourage consumption. Electricity coefficients can be used as a proxy for consumer behavioural efficiency, as the HPC sector is its largest consumer. After the 1990s, almost all OPEC member countries had higher electricity coefficients than energy ones, due to reasons spanning from higher urbanisation and population growth rates, to low electricity prices. This suggests that electricity use in the industrial and HPC sectors will be a major driver of future demand growth for those countries, especially as their service sector grows and their economies diversify.

This study attempts to predict energy intensity interactions between China, the United States, Japan and EU by developing a restricted VARX model by proposing energy intensities of the countries interact with each others, and gross domestic product (GDP) levels per capita and Organization of Petroleum Exporting Countries (OPEC) oil-based current energy prices affect energy intensities of the countries based upon the direction of group causalities. There exist significant causal interactions between energy intensities of the countries up to lag five either increasing efficiency or not. China's current GDP level affects its own energy use and EU's energy intensity positively, on the other way; EU's current GDP level affects only China's energy intensity while Japan's current GDP level only affects its own energy intensity negatively, *ceteris paribus*. It is found that OPEC oil-based current energy prices only affect the United States' energy intensity but not others' energy intensity, *ceteris paribus,* for the period of 1971–2009. Evaluating cumulative effects of energy intensities of all countries, it is found that each country has experienced higher energy intensity and consumed energy less efficiently even there have been existing new technology-embodied equipments used and alternative energy sources developed in energy consumption for the years.