Search

The hydrogen economy requires the right conditions to produce hydrogen by sustainable routes and provide it to local and international markets for suitable applications. This study evaluated the political, economic, social, technological, legal, and environmental (PESTLE) conditions that can be instrumental in adopting hydrogen technologies most effectively by encapsulating aspects relevant to key stakeholders from hydrogen technology developers through to end-users. For instance, the analysis has shown that countries within a government effectiveness index of 0.5 and −0.5 are leading the planning of hydrogen economies through strategic cooperation with hydrogen technology developers. Furthermore, the combination of a Doughnut and PESTLE analysis created a novel approach to assessing the adoption of hydrogen technologies while evaluating the impact of the hydrogen economy. For instance, the estimated ammonia demand in 2050 and subsequent anthropogenic nitrogen extraction rate will be about two and a half times more than the 2009 extraction rate.

Hydrogen presents an opportunity for Africa to not only decarbonise its own energy use and enable clean energy access for all, but also to export renewable energy. This paper developed a framework for assessing renewable resources for hydrogen production and provides a new critical analysis as to how and what role hydrogen can play in the complex African energy landscape. The regional solar, wind, CSP, and bio hydrogen potential ranges from 366 to 1311 Gt/year, 162 to 1782 Gt/year, 463 to 2738 Gt/year, and 0.03 to 0.06 Gt/year respectively. The water availability and sensitivity results showed that the water shortages in some countries can be abated by importing water from regions with high renewable water resources. A techno-economic comparative analysis indicated that a high voltage direct current (HVDC) system presents the most cost-effective transportation system with overall costs per kg hydrogen of 0.038 $/kg, followed by water pipeline with 0.084 $/kg, seawater desalination 0.1 $/kg, liquified hydrogen tank truck 0.12 $/kg, compressed hydrogen pipeline 0.16 $/kg, liquefied ammonia pipeline 0.38 $/kg, liquefied ammonia tank truck 0.60 $/kg, and compressed hydrogen tank truck with 0.77 $/kg. The results quantified the significance of economies of scale due to cost effectiveness of systems such as compressed hydrogen pipeline and liquefied hydrogen tank truck systems when hydrogen production is scaled up. Decentralization is favorable under some constraints, e.g., compressed hydrogen and liquefied ammonia tank truck systems will be more cost effective below 800 km and 1400 km due to lower investment and operation costs.

The dairy industry accounts for 9–14% of East Africa's agricultural gross development product. Due to lack of milk cooling facilities, dairy farmers in areas without access to reliable grid electricity face problems of high milk spoilage and limited access to formal markets, which limits their income and standard of living. This article examines the economic viability for a number of configurations of off-grid solar, wind, biomass and biogas based milk-cooling systems serving a community in Tanzania. Key risk factors having the greatest impact on system viability are identified and a stochastic approach, by means of a Monte Carlo simulation is employed to determine the risk-adjusted economic performance of the project. The results indicate that biogas based systems offer the most viable option, with an internal rate of return of around 25%, a net present value of around $9000 and a projected increase in farmers' monthly income of at least 78%. Despite specific risk factors, the 300-L cooling system had an 82% probability of a positive net present value. However, larger system cooling capacities have a significant likelihood of a financial loss. Consequently, risk mitigation strategies designed to increase the probability of economic success are proposed.

The lack of modern electricity supply has been a major impediment to proper functioning of the healthcare centers in the rural areas, contributing to high maternal and child mortality rates in a country. Therefore, this study focuses on how to address the identified problem so that the healthcare centers or clinics in the remote areas can provide timely delivery of medical services for the concerned people. This paper, then, presents the analysis of stand-alone hybrid renewable energy systems for basic healthcare services in the rural areas, where there is no grid energy supply or the supply from the existing grid is erratic and unreliable. One major factor that informs the selection of the hybrid energy system in this study is that it promises high reliability compared to a single energy system. The research presents a statistical analysis of the potential of wind and solar energies for a selected rural locations in Nigeria based on the available long-term hourly and daily meteorological data. It employs an optimal technical and economic design and sizing of hybrid electrical power systems’ components such as the wind, PV, battery and inverter systems, using the hybrid optimisation software (HOMER). Results show that Sokoto and Jos sites exist in the high wind potential regions, while the remaining sites are only suitable for small wind applications. Values obtained for global radiation show that all the sites enjoy considerable solar energy potential suitable for varying degree of solar energy applications. PV/wind/diesel/battery hybrid system configuration is considered optimum for rural health center at Iseyin, Sokoto, Maiduguri, Jos and Enugu, while hybrid systems involving PV/diesel/battery is considered ideal for Port-Harcourt, due to the quality of renewable energy potential. Hence, it was concluded that, the abundance of wind and solar resources in the country create an ideal environment for inclusion of renewable energy systems in the design and implementation of standalone power supply systems to improve rural healthcare delivery.

Energy poverty in the majority of the rural households in Kenya is a threat to economic and social development; hence the availability of an affordable and reliable domestic energy source is important. This study investigated: the potential resources for biogas for cooking, suitable anaerobic digesters that could be deployed in rural households, and also the viability of a small community biogas business model. Conservative estimates of the business model parameters and sensitivity analysis revealed that there was adequate biogas potential in central and western Kenya while water scarcity affected other regions' opportunities. Cattle manure was the predominant feedstock, although crop waste has possibilities to contribute to biogas production. Economically and technically, the inflatable tubular digester was found to be the most suitable type for biogas production in rural Kenya. Discounted cash flow analysis of the business model proved a profitable business to supply an affordable household energy at 0.55€/Kg of biogas, with projected household savings of 249€ annually. Labor cost was found to have high significance on the feasibility of the business model which was also sensitive to changes in biogas revenues. Kenya's rural areas have significant biogas potential to reduce energy poverty, generate income and aid social development.

Despite the strong support for exergy in thermodynamics, the industry still relies on energy based power plant efficiencies. The paper exposes errors with energy based efficiencies and improves the graphical representation of plants efficiencies. Among others, energy efficiencies cannot recognised that Combined Heat and Power (CHP) plant may be less efficient than condensing plants or that fossil fuel based plants should always be more efficient than any biomass plants because irreversibilities from biomass spontaneous thermo-chemical reactions are much higher than with coal or natural gas. Profitability equations fail to distinguish the true technical efficiency so exergy must be used, if only to enhance power plants understanding. Two novel graphs are introduced. Graph #1 combines all in a single graph; total, electrical and thermal exergy efficiencies. Graph #2 splits thermal exergy efficiency into two components related to; plant thermal losses and useful heat output quality. Data from 24 existing and design plants is used to support the graphs. Graph #1 shows different rankings of efficiencies than what is typically understood by the industry. Graph #2 shows that achieving further higher thermal energy efficiency barely increases the total exergy efficiency. If possible, it is better to increase the useful heat output quality.

This paper presents an overview of the Malawi energy situation and the potential of renewable energy resources including solar, wind, biomass, hydro and geothermal. Despite a range of efforts by local and international stakeholders to increase access to modern energy sources in the country, 89 per cent of Malawi׳s energy is still sourced from traditional biomass mainly fuel wood. Only 8 per cent of the population in Malawi have access to electricity but installed capacity of electricity generation is lower than demand. This leads to load shedding by the electricity supplier; consequently electricity supply in Malawi is unreliable and micro and macroeconomic activities are significantly affected. Solar, non-traditional biomass (crop residues and forest residues not burnt on three stone fireplaces, and biogas), hydro, wind and geothermal are potential energy resources that could enhance Malawi׳s energy security. However, unreliable financing mechanisms for large scale energy projects; shortage of trained human resource; lack of coordination among local institutions; unclear regulation enforcement; and sometimes political governance impede sustainable delivery of energy projects. The Malawi energy policy targets and drivers are also discussed in the paper. Based on the prevailing energy situation, a PESTLE analysis is provided in this paper outlining a novel thinking for addressing the political (P), economic (E), social (S), technological (T), legal (L), and environmental (E) challenges that constrain the development of renewable energy technologies in Malawi.

Solar thermal systems, that provide auxiliary energy for space heating, represent a growing opportunity in European countries like Austria and Germany. However, such systems are as yet not widely known in the rest of Europe, unlike thermosyphon water heating systems. In addition, the need for energy conservation and reduction of CO 2 emissions, to combat climate change, demands the use and advance of renewable energy sources in new sectors than for common domestic water heating. The purpose of this research work is to present a full cycle of operational results of a hybrid solar thermal-biomass space heating system in Greece. The hybrid heating system was installed at the Centre for Renewable Energy Sources (CRES), Pikermi, central Greece in September 2005 with the intension to provide all the heat requirements for a specific office block of 60 m 2 area. The system was analyzed and optimized over a period of 6 months. The solar contribution during the actual measurement period (60% of the operating period) covered 52.9% of the total heating demand. The operational results of this unit from November 2005 till April of 2006 are presented and analyzed. The main parameters presented here include the operation of the system, the results, the coverage fraction ( f %) of the solar and the biomass subsystems, the actions taken to increase its efficiency and the technical problems faced along with possible solutions to overcome them.