Technological Advancements and Future Directions in Green Energy

The energy transition, and with it the shift to renewable energy sources, is progressing. However, further measures are needed to accelerate expansion to achieve the European as well as global energy and climate goals. This chapter examines the potential of plug-and-play photovoltaic (PV) systems, which are smaller than traditional PV systems and designed to be installed without the need for professional technical knowledge. As such, this work demonstrates the functionality, applicability and economics of plug-and-play PV systems. Due to the time lag between PV generation and consumption, surpluses often occur. Conventionally, these surpluses are not utilized or remunerated, or only to a limited extent. By integrating energy storage, these surpluses can be accumulated and made available for use at a later time, which can notably increase the self-consumption and thus the economic efficiency of the system. As part of this work, the options for optimizing plug-and-play PV systems with and without energy storage are presented.

The objective of this study is to analyze the influence of various parameters on the expected lifespan of transformers, assess the economic viability for utilities and end-users to implement photovoltaic generation systems, and measure the extension of transformer lifetime. For power distribution transformers, understanding the working temperature and humidity is crucial. Abnormal values of these parameters result in electrical and mechanical stress, ultimately affecting the transformer’s lifespan.

As an alternative, distributed solar generation systems with storage in batteries were explored. Different scenarios involving solar panels and inverters were analyzed to determine the optimal solution for load relief, reduction in operating temperature, and improvement in the utilization factor, consequently enhancing the overall lifespan.

The Philippines emerged as a promising site for wave energy harvesting, considering significant wave height and wave period. A comprehensive assessment was conducted of potential ocean wave energy sites along the Philippine coastline specifically in Baler, Aurora by integrating data from Jason-2 and 3 satellite altimeters, SWAN model simulations, and in-situ measurements, utilizing Matlab and SWAN software. Rigorous validation methodologies were emphasized to ensure data accuracy through validation with in-situ measurements. The study revealed the influence of monsoon seasons on wave energy potential, offering insights into seasonal variations. Despite reduced energy potential during the westerly monsoon, significant wave energy during the easterly monsoon remained attractive. Maximum energy could be harnessed with a significant wave height of 2.5–3.0 m and a wave period of 7–8 s. These findings contribute to understanding site selection criteria, potential estimation, and methodologies in wave energy generation.

Green hydrogen (GH₂) has been considered a promising alternative to fossil fuels in chemical and energy applications. In this study, a comparative analysis is performed for the life cycle of GH₂ production, through pressurized Alkaline electrolysis (ALE), sourced with different renewable energy options in Portugal, especially hydropower, PV solar, and wind energy. GWP impact is assessed using SimaPro software concerning the construction materials and operation requirements for the hydrogen production project with 15 MW capacity and 20 years lifetime. Four electricity supply technology scenarios for the electrolyzer system are investigated, namely, hydropower, wind turbine, PV solar, and the electricity grid mix in Portugal. LCA results demonstrated that hydrogen from the hydropower scenario has the lowest GWP impact of 0.26 kg CO₂eq /kgH₂, followed by 1.76 for the wind turbine scenario, followed by 2.94 for the PV solar scenario, and 7.4 kg CO₂eq /kgH₂ for the grid mix scenario. The GWP values obtained are lower than the common conventional steam methane reforming method (11.89 kg CO₂eq /kgH₂).

With rapid urbanization, effectively separating household and construction waste is vital for environmental protection and resource recovery. This study aims to optimize the performance of disc screen equipment in separating these waste types. By adjusting the inclination angle of the disc screen and the shaft speed of the discs, the optimal parameter settings were determined to maximize separation efficiency and accuracy. The triangular disc screen equipment XS-S-1560, featuring adjustable inclination angle and shaft speed, was utilized for the experiments. Household and construction waste from the Yangzhou region of China were used as experimental materials. The results demonstrated that, for household waste, an inclination angle of 0° and a shaft speed of 75 rpm achieved a screening efficiency of 97.507%. For construction waste, an inclination angle of 14° and a shaft speed of 80 rpm resulted in a screening efficiency of 94.949%. These findings provide scientific evidence for the application of disc screen equipment in material recycling facilities, contributing to enhanced economic and environmental sustainability. The developed regression models provide reliable predictions for optimizing disc screen operations, ensuring higher purity and market value of recycled materials. This research underscores the importance of tailored optimization for different waste compositions and highlights the potential for further advancements in solid waste treatment technologies.

This study has constructed a brand-new clean and low-carbon production mode and established an oilfield as the first carbon-neutral factory for oil and gas production in China targeting Scope 1 and 2 greenhouse gas emissions. To achieve zero carbon emissions in oil and gas field enterprises through energy conservation and emission reduction measures in the production and manufacturing process is an important goal of the current transformation and development. This study systematically creates a method through energy consumption sorting, carbon verification, clean resource analysis, process energy saving optimization, scheme comparison and economic evaluation in planning layout, and implementation process of carbon-neutral factories construction. According to this method, this study sorts and optimizes the energy consumption of the central processing facility in the operation area. It utilizes solar energy, newly installs equipment such as photovoltaic module, heat pump, electromagnetic heater, and covers all the production needs with green electricity. Finally, it completely replaces the associated gas, and successfully builds carbon-neutral and achieves certification from authoritative institutions.

Promoting the use of renewable energies and reducing the emissions caused by the consumption of fossil fuels have become significant points for the global industrial community. Green hydrogen, produced from renewable sources, is a promising energy vector, but its implementation has been hurdled by its cost premium in relation to grey hydrogen. One way to increase the economic feasibility of green hydrogen is to market the byproduct O₂. In our previous work, an oxygen liquefaction process was developed to be used in a water electrolysis plant that can output liquid oxygen (LO₂) with lower specific energy consumption and cost than other O₂ production methods like cryogenic distillation (CD) and pressure swing adsorption (PSA). In this study, life cycle analysis is conducted for a 50 MW water electrolysis plant with an integrated oxygen liquefaction unit aiming at assessing its global warming potential (GWP) in four different energy supply scenarios of the Portuguese context. The energy and material balance were determined by simulation with the Aspen Plus software and then GWP impact was assessed using SimaPro software. The results demonstrated that adding an oxygen liquefaction unit to the electrolysis plant only increased the GWP by 6.5–6.8%, compared to the isolated water electrolysis plant. Additionally, the GWP of the O₂ liquefied in the unit proved to be inferior by 34–81%, depending on the energy source, when compared to the LO₂ produced at air separation units. Lastly, the cost analysis showed that for the Portuguese case, the 50/50 combination of solar photovoltaic (PV) and onshore wind energy outputs similar levelized cost of H₂ (LCOH) and levelized cost of LO₂ (LCOLO2) as the current grid mix, being the lower costs achieved when the contribution of solar is higher, reaching LCOH equal to 3.37 €/kg_H2 and LCOLO2 equal to 0.058€/kg_O2 for 80PV/20Wind ratio.

It is evident that developed economies have made significant progress in terms of renewable energy due to their early advancements. In contrast, emerging economies are falling behind in this aspect. While there has been some catching up by emerging economies in the last decade, there is still a considerable distance for them to cover. Our analysis mainly focuses on calculation of renewable energy efficiency in developed as well as in emerging economies using Stochastic Frontier Analysis or SFA, which supports the above conclusions and underscores the need for further developments. This work also introduces a non-parametric model to check for the relationship between sustainability and renewable energy efficiency. How this efficiency impacts sustainability through non-parametric estimation known as Local Linear Dummy Variable Estimation, and obtained positive results indicating a pressing need for the development of renewable energy—a contribution that will lead towards greater sustainability efforts.

The concept of sustainable green technologies in construction industry has drawn considerable attention among researchers in recent decades. Considering the significant role of passive cooling technologies in enhancing the thermal performance of residential buildings, this study explores the challenges and barriers towards the development of high-performance building envelopes incorporating passive technologies in Australia. This article is a part of an ongoing comprehensive research aiming at facilitating the adoption of high-performance passive envelopes in Australian residential sector. Through an in-depth investigation of the literature followed by interviews with construction professionals, the major barriers and their significance have been revealed. While the existing literature puts emphasis on the technological aspects of passive cooling, the results of this study reveal the crucial role of policy and regulations in mitigating the existing challenges. Insights from this research provide the construction industry managers with a comprehensive understanding of the major barriers to the adoption of passive cooling technologies and solutions to develop high-performance building envelopes.