Despite the optimism behind the growth in renewable energy (RE) and its deployment in 2011, and particularly in the aftermath of the Fukushima nuclear disaster, progress has remained inadequate and "too slow" in tackling the problem of accumulating carbon emissions in the atmosphere. Caveats have also been surfaced about the future development of RE and energy efficiency technologies since a mosaic of setbacks are hindering large scale clean energy development. In academia, perceptions of clean energy and energy efficiency technologies have been largely investigated from public acceptance point of view and to a narrower extent from the industrial and business landlords' point of view. However, studies that address these challenges to early-stage researchers and professors are limited, though they appear to play a pivotal role in advancing the science of RE. In this context, we conducted a survey-based study among a group of early-stage researchers (PhDs) and professors, who participated in two training courses in the UK and Cyprus. A total of 122 questionnaires were collected from the participants. The study found that progress in RE development was perceived to be developing moderately worldwide and hibernating in some countries. The respondents, regardless of their level of professional expertise and country's income class, perceived the prime factors hindering RE development worldwide were the lack of governmental policies, competition from fossil fuels (conventional and non-conventional), and lack of public awareness and support. Based on the respondents' geographical location, European academics perceived the lack of public support, Asian academics perceived the lack of supportive governmental policies, and African academics perceived the lack of mobilized public finance as key barriers to RE development. The participants emphasized the need to increase financial support for clean energy R&D, gradually adopt the uptake of renewables, and encourage synchronous and gradual elimination of fossil fuel subsidies. (C) 2014 Elsevier Ltd. All rights reserved.