Jonathan Whale

Recent global initiatives to increase renewable energy capacity have presented a pathway to simultaneously meet future electricity demands and achieve decarbonization. However, emerging economies have seen marginal growth partly because of ineffective energy policies enacted to propagate the adoption of these renewable energy technologies. Using Ghana as a case study, this research focused on assessing the impact of energy policies on deploying renewable energy technologies, specifically focusing on renewable energy-based hybrid mini-grids. The weighted sum multi-criteria decision and SWOT analysis methods were used to evaluate the policies' effectiveness. The results highlighted that numerous energy policies implemented across Ghana did not fully promote mini-grid development. The study showed that only the renewable energy master plan and the scaling-up renewable energy program had clearly defined strategies for mini-grid development. The study revealed that financial constraints, complex implementation strategies and limited monitoring mechanisms are the main reasons why the policies are ineffective in promoting the industry in Ghana.

This study introduces a novel approach to wind energy by investigating a novel Active Axis Wind Turbine design. The turbine is neither a horizontal nor vertical axis wind turbine but has an axis of operation that can actively change during operation. The design features a rotor with a single blade capable of dynamic pitch and tilt control during a single rotor rotation. This study examines the potential to balance the centrifugal and aerodynamic lift forces acting on the rotor blade assembly, significantly reducing blade, tower, foundation and infrastructure costs in larger-scale devices and decreasing the levelised cost of energy for wind energy. The design of a laboratory prototype rotor assembly is optimised by varying the masses and lengths in a lumped mass model to achieve equilibrium between centrifugal and lift forces acting on the turbine’s rotor assembly. The method involves an investigation of the variation of blade pitch angle to provide a balance between centrifugal and aerodynamic forces, thereby facilitating the cost advantages and opening the opportunity to improve the turbine efficiency across a range of operation conditions. The implication of this study extends to different applications of wind turbines, both onshore and offshore, introducing insight into innovation for sustainable energy and cost-effective solutions.

Energy storage in electrochemical hybrid capacitors involves fast faradaic reactions such as an intercalation, or redox process occurring at a solid electrode surface at an appropriate potential. Hybrid sodium-ion electrochemical capacitors bring the advantages of both the high specific power of capacitors and the high specific energy of batteries, where activated carbon serves as a critical electrode material. Herein, we have demonstrated that a porous honeycomb structure activated carbon derived from Australian hemp hurd (Cannabis sativa L.) in aqueous Na2SO4 electrolyte showed a specific capacitance of 240 F/g at 1 A/g. The hybrid sodium-ion device employing hemp-derived activated carbon (HAC) coupled with electrolytic manganese dioxide (EMD) in an aqueous Na2SO4 electrolyte showed a specific capacitance of 95 F/g at 1 A/g having a capacitance retention of 90%. The hybrid device (HAC||EMD) can possess excellent electrochemical performance metrics, having a high energy density of 38 Wh/kg at a power density of 761 W/kg. Overall, this study provides insights into the influence of the activation temperature and the KOH impregnation ratio on morphology, porosity distribution, and the activated carbon's electrochemical properties with faster kinetics. The high cell voltage for the device is devoted to the EMD electrode.

The introduction of phosphorous (P), and oxygen (O) heteroatoms in the natural honeydew chemical structure is one of the most effective, and practical approaches to synthesizing activated carbon for possible high-performance energy storage applications. The performance metrics of supercapacitors depend on surface functional groups and high-surface-area electrodes that can play a dominant role in areas that require high-power applications. Here, we report a phosphorous and oxygen co-doped honeydew peel-derived activated carbon (HDP-AC) electrode with low surface area for supercapacitor via H3PO4 activation. This activator form phosphorylation with cellulose fibers in the HDP. The formation of heteroatoms stabilizes the cellulose structure by preventing the formation of levoglucosan (C6H10O5), a cellulose combustion product, which would otherwise offer a pathway for a substantial degradation of cellulose into volatile products. Therefore, heteroatom doping has proved effective, in improving the electrochemical properties. The improved performance is attributed to the high phosphorous doping with a hierarchical porous structure, which enables the transportation of ions at higher current rates. The high specific capacitance of 486, and 478 F/g at 0.6, and 1.3 A/g in 1M H2SO4 electrolyte with a prominent retention of 98% is observed for 2M H3PO4 having an impregnation ratio of 1:4.

With less than seven years before the UN’s Sustainable Development Goals deadline, the race is on to achieve universal access to affordable, reliable and modern energy services in low-income communities in developing countries. These communities are mostly distant from central grids and economically suitable for off-grid mini-grid systems. Data suggest that these mini-grids are not sustained and often fail after a few years of operation. The authors investigated the challenges of an existing mini-grid system in Ghana and proposed measures to overcome them. Field surveys with expert stakeholders and users of the system were conducted to examine the challenges. The results showed that 98% of the residents use power for domestic purposes. The inability to pay for the power consumed was the highest-ranked challenge the users faced followed by power quality issues. From the expert stakeholders’ perspectives, economic challenges were the most significant barriers with a mean score range of 3.92 to 4.73 on a 1–5 Likert scale, followed by political challenges. The researchers propose that implementers must optimize non-hardware costs and promote local component manufacturing to address these economic challenges. In addition, we suggest that the government review the government-driven policy and involve the private sector.

Off-grid hybrid power systems with renewable energy as the primary resource remain the best option to electrify rural/remote areas in developing countries to help attain universal electricity access by 2030. However, deploying these systems in West Africa faces several challenges and regularly fail to transition from pilot, donor-sponsored projects to sustainable large-scale implementations. The study examined the drivers and challenges by conducting a review of previous studies done in the region and a short survey in Ghana. Using Political, Economic, Social, Technical, Legal and Environmental dimensions, the review and survey showed that economic challenges have the worst impacts on the sustainable development of off-grid renewable energy-based power systems in WA. Further, the analysis revealed patterns and linkages among the challenges that make it detrimental to focus solely on the most pressing challenges.

Transition to a low carbon economy has a unique set of circumstances which present both challenges and opportunities for the development of its energy policies and require customised energy planning solutions and policies. Each country begins its path to decarbonization from a different starting point. The Northern Territory (NT) of Australia has one of the highest rates of solar insolation in Australia which can be a catalyst for future energy development. This study explores the potential for long-range renewable energy (RE) planning and climate policies for the NT to transition to a low-carbon economy by 2050, while achieving sustainable economic growth by analysing three scenarios: business-as-usual (BAU), High Industry Growth (HIG) and Renewable Energy Export (REE). The results showed that slight variations in inputs and assumptions can affect the need and timing of appropriate policies to support a desired outcome or goal. In conclusion, a low-emissions economy based on an industry powered by renewable energy is possible with the support of a range of effectively timed energy and climate policies. Effective energy transition policies would need to be developed with careful consideration of the unique circumstances and existing barriers in the NT. The future could be a combination of elements in both HIG scenario and a REE scenario. If implemented and sequenced appropriately, energy policies can be effective in laying the groundwork for a smoother transition to low-carbon economy in the NT.

Renewable energy generation and increased electrification are pivotal to reducing greenhouse gas emissions and mitigating climate change. Consequently, global deployment of wind turbines has soared, and the trend is expected to continue. Installed turbines have only recently started reaching the end of their design lives, and waste volumes are projected to escalate rapidly. Approximately 94% of a wind turbine (by mass) is recyclable, but the waste polymer composite blades are most commonly landfilled. This mini-review aims to review current end-of-life (EoL) management practices in the large-scale wind industry for countries with established EoL standards as well as those with less mature regulations. Data on current EoL management practices, initiatives and regulations in industry was sourced primarily from literature reviews and publicly available internet information. Additional insights and perspectives were gained from WindEurope’s EoL Issues and Strategies 2020 seminar and through communication with select individuals from various sectors such as wind energy development and operations, government, industry associations, academia and research organizations. The results show that the decision on EoL options is dictated by the remaining useful life (RUL) of the wind turbines, prevailing policies and electricity prices. The contribution of this article is, firstly, identifying a number of key technical, economic and regulatory questions that must be asked before deciding on the most appropriate EoL option. Secondly, the article identifies factors that impede current EoL management efforts to close the circular economy gap and those that can support sustainable technology deployment. Finally, the article considers the way that countries with a young fleet of wind farms may learn from more experienced nations. There are few proven business cases, and barriers to the profitability and effectiveness of EoL strategies include uncertainty about the assets’ RUL, collection logistics, the size of wind farm operation margins, low waste feedstock and limited markets for recycled products. Designing for circularity, stakeholder collaboration, circular business models and technology-specific regulations can improve EoL sustainability. The research found that wind turbine EoL management is dynamic and complex and needs to consider multiple, often conflicting factors. However, it is necessary and has immense environmental, technical and economic potential as the industry matures and business cases are proven.

Nickel-based bimetallic oxides (BMOs) have shown significant potential in battery-type electrodes for pseudo-capacitors given their ability to facilitate redox reactions. In this work, two bimetallic oxides, NiMoO4 and NiWO4, were synthesized using a wet chemical route. The structure and electrochemical properties of the pseudo-capacitor cathode materials were characterized. NiMoO4 showed superior charge storage performance in comparison to NiWO4, exhibiting a discharge capacitance of 124 and 77 F·g−1, respectively. NiMoO4, moreover, demonstrates better capacity retention after 1000 cycles with 87.14% compared to 82.22% for NiWO4. The lower electrochemical performance of the latter was identified to result from the redox behavior during cycling. NiWO4 reacts in the alkaline solution and forms a passivation layer composed of WO3 on the electrode, while in contrast, the redox behavior of NiMoO4 is fully reversible.

Knowledge of the turbulence in the wakes of wind turbines is important to improve the operation and lifetime of downstream turbines exposed to these wakes. As the investigation of a rotating turbine can be challenging, both experimentally and numerically, static actuator discs can substitute rotating turbines. To investigate the similarity of the turbulence in the wakes and how turbulent inflow alters the result, an experimental wind tunnel study is presented that compares hot-wire measurements in the central wakes of an actuator disc and a model wind turbine (diameter-based Reynolds number Re ≈ 300000). Two turbulent inflows are investigated, an intermittent, i.e. gusty, atmospheric-like inflow generated by an active grid, and a non-intermittent inflow generated by a regular grid. The data is investigated using one-point and higher-order two-point statistics. We find that the wakes of both models have similar properties for all investigated quantities within the far wake. The turbulence in the central wake is independent of the inflow conditions, and both models filter larger scale intermittency in the far wake with regard to the inflow. Also, we find that the turbine generates its own kind of turbulence that dominates the ambient turbulence and has strong features of homogeneous, isotropic turbulence.