Reducing the total emissions of energy generation systems is a pragmatic approach for limiting the environmental pollution and associated climate change problems. Socio economic activities in the ...21st century is highly determined by the energy generation mediums, particularly the renewable resources, across the world. Therefore, a thorough investigation into the technologies used in harnessing these energy generation mediums should contribute to their further advancement. Concentrated Solar Photovoltaics (CSP) and Enhanced Geothermal Energy (EGE) are considered as emerging renewable energy technologies with high potential to be used as suitable replacements for fossil products (petroleum, coal, natural gas etc.). Despite the accelerated developments in these technologies, they are still facing many challenges in terms of cost. This review paper presents a detailed background about these renewable energy technologies and their main types such as solar tower, parabolic trough, and so on. Also, the principle challenges impeding the advancement of these energy technologies into commercialisation are discussed. Possible solutions for the main challenges are presented and the future prospects for such energy generation mediums are reported.
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•Technologies for harnessing concentrated solar photovoltaics and enhanced geothermal energy are thoroughly discussed.•Challenges impeding the advancement of these energy generation mediums are also presented.•The future prospects of concentrated solar photovoltaics and enhanced geothermal energy are captured in this investigation.•Some recommendations for easy commercialization of these technologies are also reported.
•Pretreat the waste paper for 60min improves the methane yield by 20.60%.•The highest methane yields were achieved at F/I ratio 0.3.•The net energy was positive for all process conditions with a ...maximum of 2.19Wh/gVS.•Response surface methodology (RSM) with a Composite Central Design (CCD) was applied.•An optimized methane yield of 253.62ml/gVS was achieved for 55min pretreatment and 0.3 of F/I ratio.
In the anaerobic digestion of lignocellulosic materials such as waste paper, the accessibility of microorganisms to the fermentable sugars is restricted by their complex structure. A mechanical pretreatment with a Hollander beater was assessed in order to reduce the biomass particle size and to increase the feedstock’ specific surface area available to the microorganisms, and therefore improve the biogas yield. Pretreatment of paper waste for 60min improves the methane yield by 21%, from a value of 210ml/gVS corresponding to untreated paper waste to 254ml/gVS. 30min pretreatment have no significant effect on the methane yield. A response surface methodology was used to evaluate the effect of the beating time and feedstock/inoculum ratio on the methane yield. An optimum methane yield of 253ml/gVS was achieved at 55min of beating pretreatment and a F/I ratio of 0.3.
Cell walls and lignin component disruption treatments are needed to enhance the hydrolytic phase and the overall biodegradability of lignocellulosics during an anaerobic digestion process. Given ...their abundant availability in nature, low impact on food market prices and low lignin content, aquatic plants result in being particularly suitable for biofuel conversion.
A preliminary study on the effects of a Hollander beater mechanical pretreatment has been conducted in batch mode focusing on biogas yields from five different species of Irish seaweeds in co-digestion with sludge. A second experiment on Laminaria Digitata species has been carried out using a Response Surface Methodology (RSM) with treatment times (0–10 min), mesophilic range of temperatures (35–39 °C) and sludge amounts (100–300 ml). Results from biogas yields of treated macroalgae have been found to be up to 20% higher when compared to untreated ones. A mathematical model of the biogas volume behaviour has been developed and the ideal conditions identified.
► Relates different seaweed species to biogas yield and evaluates extra biogas yield from mechanical pretreatment. ► Compares co-digestion of treated/untreated macroalgae to sludge-only digestion. ► Mechanically pretreated feedstock produced up to 13% extra biogas. ► No significant effect by temperature variations in the mesophilic range 35–39 °C. ► Contains optimisation conditions for fermentation of Laminaria sp. to biogas.
Microbial fuel cells (MFCs) are energy conversion devices that simultaneously produce electricity while degrading the wastewater's organic materials. Despite the high potential of the MFCs for ...wastewater treatment, the relatively low power output and the cost of commercially available electrode materials impact their commercialization negatively. Carbon-based nanomaterials (CBNMs) can be used effectively as standalone anode material. However, carbon-based anodes are usually modified to enhance the mechanical and chemical stabilities, increase the electroactive surface area, improve biocompatibility, and increase the electrical conductivity, promoting biofilm formation and/or the electron transfer rate. Moreover, CBNMs can be used at the cathode to support the catalyst or as a standalone non-precious catalyst. This work introduced and discussed the application of different CBNMs, including carbon nanofibers, carbon nanotubes, graphene, graphitic carbon nitrites, and their derivatives or composites in microbial fuel cells.
•Microbial fuel cell performance is discussed.•Application of graphene in microbial fuel cell is presented.•Factors impeding the commercialization of microbial fuel cell is analysed.•Prospects of microbial fuel cell is evaluated and discussed.
Combined heat and power (CHP) in a single and integrated device is concurrent or synchronized production of many sources of usable power, typically electric, as well as thermal. Integrating combined ...heat and power systems in today’s energy market will address energy scarcity, global warming, as well as energy-saving problems. This review highlights the system design for fuel cell CHP technologies. Key among the components discussed was the type of fuel cell stack capable of generating the maximum performance of the entire system. The type of fuel processor used was also noted to influence the systemic performance coupled with its longevity. Other components equally discussed was the power electronics. The thermal and water management was also noted to have an effect on the overall efficiency of the system. Carbon dioxide emission reduction, reduction of electricity cost and grid independence, were some notable advantages associated with fueling cell combined heat and power systems. Despite these merits, the high initial capital cost is a key factor impeding its commercialization. It is, therefore, imperative that future research activities are geared towards the development of novel, and cheap, materials for the development of the fuel cell, which will transcend into a total reduction of the entire system. Similarly, robust, systemic designs should equally be an active research direction. Other types of fuel aside, hydrogen should equally be explored. Proper risk assessment strategies and documentation will similarly expand and accelerate the commercialization of this novel technology. Finally, public sensitization of the technology will also make its acceptance and possible competition with existing forms of energy generation feasible. The work, in summary, showed that proton exchange membrane fuel cell (PEM fuel cell) operated at a lower temperature-oriented cogeneration has good efficiency, and is very reliable. The critical issue pertaining to these systems has to do with the complication associated with water treatment. This implies that the balance of the plant would be significantly affected; likewise, the purity of the gas is crucial in the performance of the system. An alternative to these systems is the PEM fuel cell systems operated at higher temperatures.
Low temperature hydrogen fuel cells are electrochemical devices which offer a promising alternative to traditional power sources. Fuel cells produce electricity with a reaction of the fuel (hydrogen) ...and air. Fuel cells have the advantage of being clean; only producing water and heat as by products. The efficiency of a fuel cell varies depending on the type; SOFC with CHP for example, can have a system efficiency of up to 65%.
What the Authors present here is a comparison between three different configurations of flow plates of a proton exchange membrane fuel cell, the manufacturer’s serpentine flow plate and two new configurations; the maze flow plate and the parallel flow plate. A study of the input parameters affecting output responses of voltage, current, power and efficiency of a fuel cell is performed through experimentation. The results were taken from direct readings of the fuel cell and from polarisation curves produced. This information was then analysed through a design of experiment to investigate the effects of the changing parameters on different configurations of the fuel cell’s flow plates.
The results indicate that, in relation to current and voltage response of the polarisation curve and the corresponding graphs produced from the DOE, the serpentine flow plate design is a much more effective design than the maze or parallel flow plate design. It was noted that the parallel flow plate performed reasonably well at higher pressures but over all statically the serpentine flow plate performed better.
Membrane-based technologies are recently being considered as effective methods for conventional water and wastewater remediation processes to achieve the increasing demands for clean water and ...minimize the negative environmental effects. Although there are numerous merits of such technologies, some major challenges like high capital and operating costs . This study first focuses on reporting the current membrane-based technologies, i.e., nanofiltration, ultrafiltration, microfiltration, and forward- and reverse-osmosis membranes. The second part of this study deeply discusses the contributions of membrane-based technologies in achieving the sustainable development goals (SDGs) stated by the United Nations (UNs) in 2015 followed by their role in the circular economy. In brief, the membrane based processes directly impact 15 out of 17 SDGs which are SDG1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16 and 17. However, the merits, challenges, efficiencies, operating conditions, and applications are considered as the basis for evaluating such technologies in sustainable development, circular economy, and future development.
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•Membrane-based technologies for water and wastewater remediation were summarized.•Challenges facing the development of Membrane-based technologies were discussed.•The role of Membrane-based technologies in achieving SDGs was introduced.•The role of Membrane-based technologies in the circular economy was analyzed.
The EU has set a target to reduce the reducing greenhouse gas emissions by 80–95% in 2050 in comparison to 1990. To implement this roadmap it is necessary to develop the world capacity of using ...renewable energy.
This roadmap can't be implemented without driving the energy market toward 100% renewable and sustainable energy. Connolly et al. 1 have studied the scenario for a 100% renewable energy system in Europe by the year 2050. The transition from a business-as-usual situation in 2050, to a 100% renewable energy Europe has been analysed and discussed. Thellufsen and Lund 2 looked at the transition towards a 100% renewable energy system, it was concluded that energy savings are essential and should be obtained from all types of energy consumption, such as, heating, electricity sectors, industry, and transport.
This editorial presents the different talk and concepts presented at SEEP2014 in Dubai, the conference discussed the recent developments on sustainable energy and environment. One of the keynote presented the concept of Energy Quadrilemma versus Energy Trilemma, it can be seen the strong emphasis on the four different areas (Cost, Environment, Security and Job Opportunities) supporting the movement toward 100% renewable energy, Fig. 1 summarize both concepts.
Ireland with its resource of wind has the potential to use this natural resource and sustain the country’s power needs for the future. However, one of the biggest drawbacks to renewable energy ...generation, particularly wind-generated electricity is that it is an intermittent and a variable source of power. Even at the “best” sites wind varies dramatically from hour to hour and minute to minute. This leads to two main problems:
1) When the wind drops below a lower limit or goes above a higher limit the turbine can shut down and electricity is not produced.
2) Energy is not stored when there is an excess of electricity generated on site.
Because of these problems wind power has a very low capacity credit and backup power is needed to handle the large fluctuation of production.
This paper introduces the current energy system in Ireland and the targets that Irish operators are to achieve in the next decade. A review of energy storage options for Ireland is outlined including the use of hydrogen and fuel cell technology. It is concluded that a project similar to the Norwegian Utsira wind/hydrogen project could be piloted in Ireland and a site similar to Dundalk Institute of Technology could be used to demonstrate and test the system. Going forward to achieve high levels of renewable energy generation, similar distributed wind/hydrogen hybrid systems could reduce the need for curtailment of wind farms, save wasted energy, reduce backup power, reduce transmission losses, generate large revenue by selling power at peak times, ensure security of supply and reduce the need for costly interconnects to Europe.
The reliance on fossil fuels is one of the most challenging problems that need to be dealt with vigorously in recent times. This is because using them is not sustainable and leads to serious ...environmental issues, such as: air pollution and global warming. This condition affects economic security and development. An alternative to fossil fuel is highly possible which will be more environmentally friendly, sustainable and efficient as well. Among all the different technologies associated with renewable energy, fuel cell technologies represent one of the most promising technological advancement to curb the situation.
In this paper, an overview of the technology and its advantages and disadvantages compared with competitive technologies was revealed. The application of different fuel cell types in the stationary and portable sectors was covered. Furthermore, recent challenges and promising developments of current fuel cell technologies in different studied applications were reviewed. Some possible solutions to the challenges were named in this paper for both the portable and stationary fuel cell applications. The paper further seeks to expose the world to the current progress made in the fuel cell industry up to date and possible areas that needs intensified research and modifications to make the fuel cell industry more vibrant and buoyant.
•Overview of the fuel cell technology is given.•Recent challenges facing the fuel cell market in stationary and portable sectors were reviewed.•Up-to-date promising developments of fuel cell technologies in the stationary and portable sectors were covered.
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