Zhen Q. Wang, Heng Song, Noritaka Hara et al.

• 2020

Living systems provide a promising approach to chemical synthesis, having been optimized by evolution to convert renewable carbon sources such as glucose to an enormous range of small molecules. However, a large number of synthetic structures can still be difficult to obtain solely from cells, such as unsubstituted hydrocarbons. In this work, we demonstrate the use of a hybrid cellular-heterogeneous catalytic strategy to produce olefins from glucose, using a selective hydrolase to generate an activated intermediate that is readily deoxygenated. Using a new family of iterative thiolase enzymes, we have genetically engineered a microbial strain that produces 4.3 ± 0.4 g L−1 of fatty acid from glucose with 86% captured as 3-hydroxyoctanoic and 3-hydroxydecanoic acids. This 3-hydroxy substituent serves as a leaving group enabling heterogeneous tandem decarboxylation-dehydration routes to olefinic products on Lewis acidic catalysts without the additional redox input required for enzymatic or chemical deoxygenation of simple fatty acids.

A. Dabai, K. Mohammed

Platform : A Journal of Science and Technology • 2021

An enormous amount of wastewater was produced due to domestic, municipal, agricultural, and industrial activities of varying strength and contamination. These usually contained a high level of pollutants that include inorganic and organic pollutants, pesticides, and heavy metals. Physio-chemical treatment approaches were employed to treat these recalcitrant contaminants and effectively handle extremely toxic substances within a short period. However, despite this, these treatments were associated with setbacks, including incomplete pollutant removals, lack of multiple pollutants removal capabilities, excessive sludge production, and cost of energy and chemical employed. Hybrid microbial treatment systems were efficient due to their potential to remove multiple contaminants like heavy metals, BOD, COD, assimilate nutrients, production of renewable energy alternatives, and easily recycled or regenerated. The future bottleneck in terms of best microbial proportions for higher growth rates and removal efficiencies is highlighted. Keywords: algae, bacteria, proportion, heavy metals, adsorption, toxic

Xiaocheng Jiang, Jinsong Hu, Alexander M Lieber et al.

Nano Letters • 2014

Microbial fuel cells (MFCs) have been the focus of substantial research interest due to their potential for long-term, renewable electrical power generation via the metabolism of a broad spectrum of organic substrates, although the low power densities have limited their applications to date. Here, we demonstrate the potential to improve the power extraction by exploiting biogenic inorganic nanoparticles to facilitate extracellular electron transfer in MFCs. Simultaneous short-circuit current recording and optical imaging on a nanotechnology-enabled platform showed substantial current increase from Shewanella PV-4 after the formation of cell/iron sulfide nanoparticle aggregates. Detailed characterization of the structure and composition of the cell/nanoparticle interface revealed crystalline iron sulfide nanoparticles in intimate contact with and uniformly coating the cell membrane. In addition, studies designed to address the fundamental mechanisms of charge transport in this hybrid system showed that charge transport only occurred in the presence of live Shewanella, and moreover demonstrated that the enhanced current output can be attributed to improved electron transfer at cell/electrode interface and through the cellular-networks. Our approach of interconnecting and electrically contacting bacterial cells through biogenic nanoparticles represents a unique and promising direction in MFC research and has the potential to not only advance our fundamental knowledge about electron transfer processes in these biological systems but also overcome a key limitation in MFCs by constructing an electrically connected, three-dimensional cell network from the bottom-up.

K R S Pamintuan, A J S Gonzales, B M M Estefanio et al.

IOP Conference Series: Earth and Environmental Science • 2018

Plant-microbial fuel cells (PMFCs) are an emerging renewable energy source that can utilize wasted organic matter to produce electricity. In this study, the PMFC technology was hybridized to include phytoremediation of nickel. The main purpose of this study was to determine the effect of combining PMFC technology with phytoremediation of nickel. Three systems were designed for this study. System A is a control for PMFC, system B is a control for phytoremediation, and system C is the combination of the two processes. The combined PMFC and phytoremediation system showed that it has a significantly higher power output than the control (system A). The control PMFC had a maximum power density of 0.29 mW/m2, while the hybrid process produced a maximum power density of 0.86 mW/m2 which is three times than the output of the control. In terms of the Ni2+ uptake, the control recorded a metal uptake of 108.79 μg/g dry weight, lower than the Ni2+ uptake of the combined process at 212.42 μg/g dry weight. Overall, the positive results of this study is recommended to be replicated and tested with other plants and heavy metals to establish a new hybrid process of bioelectricity generation and phytoremediation.

Liang Tan, Yide Yang, Nan Li et al.

Catalysis Science & Technology • 2017

Microbial fuel cells (MFCs), as an ideal device, are highly attractive for renewable and sustainable energy storage. On the other hand, the development of low-cost and efficient catalysts based on earth-abundant elements for the sluggish oxygen reduction reaction (ORR) has remained elusive. Herein, a robust non-precious metal-based electrocatalyst is demonstrated, consisting of nitrogen-doped carbon hollow spheres elaborately decorated with Co3O4 nanoparticles (HCN-Co3O4). The unique structure of HCN-Co3O4 fully enables the utilization of synergistic effect of the high activity of Co3O4 and the excellent conductivity of HCN, endowing the hybrid with an excellent ORR catalytic activity in MFCs. Benefiting from intriguing structural features, HCN-Co3O4 exhibits a significantly enhanced electrocatalytical performance towards the ORR both in alkaline and neutral conditions, superior cycling stability, and outstanding durability compared to pure Co3O4 and hollow Co3O4 (H-Co3O4) spheres. Moreover, the high power density of the self-assembled MFCs equipped with the HCN-Co3O4 cathode also indicates the feasibility of the catalyst for practical applications.

M. Islam, L. Chen, J. Sisler et al.

Journal of Materials Chemistry B • 2018

Cellulose nanocrystal (CNC), a class of sustainable nanomaterial derived from forest and agro-biomass can serve as nature's storage for carbon dioxide. It has many attractive features, such as large specific surface area, high tensile strength and stiffness, abundance of surface hydroxyl groups, and they are also biocompatible, biodegradable and renewable. When dispersed in a polar solvent, they assemble to form multiphase or higher order structures yielding desirable optical and structural properties. They are being explored as templates for the design of a wide range of new functional nanomaterials. CNCs are excellent support for the loading of inorganic nanoparticles (e.g. Ag, Au, Pt, Pd etc.) yielding stable nano-hybrids in aqueous media. Additional surface functionalization of CNCs impart new and attractive physicochemical properties that are being exploited for application in sensors, catalysts, drug delivery vehicles, anti-microbial agents, scaffold for tissue engineering, biomarkers etc. This review provides an overview and future perspective on recent advances in the development on functional CNC-inorganic hybrids with potential applications in biomedical and chemical systems.

M. Fasihi, Fatemeh Jouzi, Petri Tervasmäki et al.

Nature Communications • 2025

The environmental impacts of the food system exceed several planetary boundaries, with protein production being a major contributor. Single-Cell Protein (SCP) is a protein-rich microbial biomass that offers a sustainable alternative when derived from renewable energy and sustainable feedstocks. We evaluate the global potential for SCP production utilising electrolytic hydrogen and oxygen, atmospheric carbon dioxide and nitrogen, and hourly-optimised hybrid PV-wind power plants at a 0.45° × 0.45° spatial resolution. We outline a roadmap for industrial-scale production, commencing in 2028, targeting an annual capacity of 30 million tonnes of protein by 2050. Here we show that the cost of renewable electricity-based protein (e-protein) could decline at optimal sites from 5.5–6.1 € kg−1 in 2028 to 4.0–4.5 € kg−1 by 2030, and further to 2.1–2.3 € kg−1 by 2050. Consequently, e-protein production can mostly decouple protein supply from water and arable land constraints, substantially mitigating the environmental impacts of food production.

Arul M. Varman, Rhiannon Follenfant, Fang Liu et al.

Biotechnology for Biofuels • 2018

BackgroundEngineering strategies to create promoters that are both higher strength and tunable in the presence of inexpensive compounds are of high importance to develop metabolic engineering technologies that can be commercialized. Lignocellulosic biomass stands out as the most abundant renewable feedstock for the production of biofuels and chemicals. However, lignin a major polymeric component of the biomass is made up of aromatic units and remains as an untapped resource. Novel synthetic biology tools for the expression of heterologous proteins are critical for the effective engineering of a microbe to valorize lignin. This study demonstrates the first successful attempt in the creation of engineered promoters that can be induced by aromatics present in lignocellulosic hydrolysates to increase heterologous protein production.ResultsA hybrid promoter engineering approach was utilized for the construction of phenolic-inducible promoters of higher strength. The hybrid promoters were constructed by replacing the spacer region of an endogenous promoter, PemrR present in E. coli that was naturally inducible by phenolics. In the presence of vanillin, the engineered promoters Pvtac, Pvtrc, and Pvtic increased protein expression by 4.6-, 3.0-, and 1.5-fold, respectively, in comparison with a native promoter, PemrR. In the presence of vanillic acid, Pvtac, Pvtrc, and Pvtic improved protein expression by 9.5-, 6.8-, and 2.1-fold, respectively, in comparison with PemrR. Among the cells induced with vanillin, the emergence of a sub-population constituting the healthy and dividing cells using flow cytometry was observed. The analysis also revealed this smaller sub-population to be the primary contributor for the increased expression that was observed with the engineered promoters.ConclusionsThis study demonstrates the first successful attempt in the creation of engineered promoters that can be induced by aromatics to increase heterologous protein production. Employing promoters inducible by phenolics will provide the following advantages: (1) develop substrate inducible systems; (2) lower operating costs by replacing expensive IPTG currently used for induction; (3) develop dynamic regulatory systems; and (4) provide flexibility in operating conditions. The flow cytometry findings strongly suggest the need for novel approaches to maintain a healthy cell population in the presence of phenolics to achieve increased heterologous protein expression and, thereby, valorize lignin efficiently.

Yuxiao Wu, Manish Shetty, Kechun Zhang et al.

• 2021

Combined chemical technologies of microbial fermentation and thermal catalysis provides a hybrid process for sustainable manufacturing of biorenewable sugar-derived monomers for plastics. In this work, methacrylic acid (MAA), a target molecule for the polymer industry, was produced from biomass-derived glucose through the intermediate molecule, citramalic acid. The biosynthetic pathway engineered in E. coli produced citramalic acid intermediate with a high yield (91% of theoretical maximum) from glucose by overexpressing citramalate synthase, removing downstream degradation enzyme 3-isopropylmalate dehydratase, and optimizing the fermentation medium. Thermal heterogeneous catalysis converted the citramalate intermediate to methacrylic acid (MAA) via decarboxylation and dehydration. A selectivity of ~71% for the production of MAA and its intermediate α-hydroxybutyric acid was achieved at a temperature of 250 oC and an acidity of 1.0 mol acid/mol citramalate. An alumina catalyst was found to enhance selectivity to MAA in a single reactor pass from 45.6% in the absence of catalyst to 63.2%. This limited selectivity to MAA was attributed to equilibrium between MAA and α-hydroxybutyric acid, but overall process selectivity to MAA was shown to be higher upon separation and recycle of reaction intermediates. A process flow diagram was proposed of the hybrid route for the conversion of glucose to the final end product, methacrylic acid, for poly(methyl methacrylate) (PMMA).

S. A. Qamar, A. Riasat, Muhammad Jahangeer et al.

Journal of Basic Microbiology • 2022

Polysaccharides are biobased polymers obtained from renewable sources. They exhibit various interesting features including biocompatibility, biodegradability, and nontoxicity. Microbial polysaccharides are produced by several microorganisms including yeast, fungi, algae, and bacteria. Microbial polysaccharides have gained high importance in biotechnology due to their novel physiochemical characteristics and composition. Among microbial polysaccharides, xanthan, alginate, gellan, and dextran are the most commonly reported polysaccharides for the development of biomimetic materials for biomedical applications including targeted drug delivery, wound healing, and tissue engineering. Several chemical and physical cross‐linking reactions are performed to increase their technological and functional properties. Owning to the broad‐scale applications of microbial polysaccharides, this review aims to summarize the characteristics with different ways of physical/chemical crosslinking for polysaccharide regulation. Recently, several biopolymers have gained high importance due to their biologically active properties. This will help in the formation of bioactive nutraceuticals and functional foods. This review provides a perspective on microbial polysaccharides, with special emphasis given to applications in promising biosectors and the subsequent advancement on the discovery and development of new polysaccharides for adding new products.

Karunakaran Venkatesan, Uma Govindarajan

Journal of Renewable and Sustainable Energy • 2019

<jats:p>This paper proposed an optimal control technique for power flow control of hybrid renewable energy systems (HRESs) like a combined photovoltaic and wind turbine system with energy storage. The proposed optimal control technique is the joined execution of both the whale optimization algorithm (WOA) and the artificial neural network (ANN). Here, the ANN learning process has been enhanced by utilizing the WOA optimization process with respect to the minimum error objective function and named as WOANN. The proposed WOANN predicts the required control gain parameters of the HRES to maintain the power flow, based on the active and reactive power variation in the load side. To predict the control gain parameters, the proposed technique considers power balance constraints like renewable energy source accessibility, storage element state of charge, and load side power demand. By using the proposed technique, power flow variations between the source side and the load side and the operational cost of HRES in light of weekly and daily prediction grid electricity prices have been minimized. The proposed technique is implemented in the MATLAB/Simulink working stage, and the effectiveness is analyzed via the comparison analysis using the existing techniques.</jats:p>

Yadala Pavankumar, Ravindra Kollu, Sudipta Debnath

IET Renewable Power Generation • 2021

<jats:title>Abstract</jats:title><jats:p>The variable nature of the renewable energy resources (RES) complicates their modelling, operation, and integration to the grid. Therefore, it is difficult to choose optimal RES with a proper energy storage system (ESS) for the economic and reliable operation of the grid‐integrated hybrid renewable energy system (HRES). There is a need to solve this optimal HRES problem using efficient algorithms due to the high cost and model complexity involved. In this study, optimal photovoltaic, wind, biomass, and battery‐based grid‐integrated HRES is proposed using a multi‐objective artificial cooperative search algorithm (MOACS) to minimise annual life cycle costing and loss of power supply probability. ESS is chosen to provide a backup power supply for at least 30 min during peak load condition. A probabilistic approach is used to consider the time‐varying nature of the RES and load while solving optimal HRES design problem by employing MOACS. A comparative analysis is provided at the end, which shows that MOACS can provide a better optimal design of HRES.</jats:p>

Shanmuganatha Vadivel Kasi, Narottam Das, Sanath Alahakoon et al.

IET Renewable Power Generation • 2025

<jats:title>Abstract</jats:title><jats:p>Renewable energy sources (RES) are vital for addressing fossil fuel challenges and promoting environmental sustainability by reducing air pollution. Hybrid RES (HRES) in microgrids (MGs) enhance energy efficiency and reliability but face issues like energy management, load demand, and efficiency. Existing research on HRES in MGs often lacks efficiency, reliability, and accuracy. This model proposes a solution using ant lion colony optimization with particle swarm optimization (ALCO‐PSO) for Maximum Power Point Tracking (MPPT) to improve power efficiency. The ant colony optimization (ACO) algorithm offers higher efficiency and better global search, but suffers from limitations such as computational complexity and premature convergence. The lion optimization algorithm (LOA) addresses these issues, enhancing the algorithm's robustness. However, ALCO faces challenges like limited scalability and global search ability, which are overcome by integrating particle swarm optimization (PSO). Additionally, direct current (DC) fault detection is enhanced using an artificial neural network (ANN) with solar data. The model's performance is evaluated using power, voltage, and power quality metrics, achieving 99.56% accuracy, faster convergence (0.11 s), an oscillation around 4.25 W, a tracking time of 0.2 s, an interruptible load of 0.009%, cost of energy (COE) of 0.0413%, and a penalty of 0.94 $/kWh.</jats:p>

P Nagasekhara Reddy, K Prashanth

Solar Energy Systems and Smart Electrical Grids for Sustainable Renewable Energy • 2025

<jats:p>The growing adoption of hybrid renewable energy systems (HRES) necessitates advanced optimization strategies to ensure efficiency, reliability, and sustainability in modern power grids. The integration of multi-technology energy storage solutions plays a crucial role in mitigating the intermittent nature of renewable energy sources, enhancing grid stability, and enabling real-time energy management. This book chapter explores the role of hybrid energy storage systems in optimizing renewable energy utilization through intelligent control mechanisms, predictive analytics, and decentralized energy management frameworks. The convergence of artificial intelligence (AI), blockchain, and multi-objective optimization techniques facilitates adaptive decision-making, efficient power distribution, and enhanced energy security. Decentralized energy storage networks and AI-driven demand-side optimization strategies improve grid resilience while minimizing transmission losses. Challenges related to storage system interoperability, economic feasibility, and large-scale implementation are critically analyzed, along with potential solutions leveraging emerging technologies. By addressing these key aspects, this chapter provides a comprehensive foundation for optimizing hybrid renewable energy systems in the evolving landscape of smart grids.</jats:p>

Luis Recalde, Hong Yue, William Leithead et al.

Volume 10: Ocean Renewable Energy • 2019

<jats:title>Abstract</jats:title> <jats:p>Integrating marine renewables and aquaculture is a complex task. The generated power of each renewable technology depends on its source cycle (wind, wave, solar PV), leading to periods of zero power production. On the other side, aquaculture farms require smooth and stable power supply since any power shortage can lead to the loss of the entire farm production. This paper illustrates the sizing of a hybrid energy system (wind,solar PV, energy storage) to power up the aquaculture farm. The sizing is based on available commercial technology and the system is mounted on a single multi-purpose platform. Reliability is improved by considering device redundancies. Such hybrid system has not been considered before for aquaculture farms. System rough sizing, based on simple online renewable energy calculators, is used to select existing renewable technologies and HOMER Pro simulation software is used to evaluate the technical and economic feasibility of the microgrid for all possible combinations of the technology selected and perform sensitivity analysis on wind turbine tower height, battery state of charge and solar PV panels reflectance. The optimisation is subject to combined dispatch strategy and net present cost.</jats:p>

Farnam Dehghani, Mohammad Agha Shafiyi

IET Renewable Power Generation • 2023

<jats:title>Abstract</jats:title><jats:p>Renewable energy sources play an important role in providing clean energy for future electricity networks. As the penetration level of these resources grows, their integration with the grid will be more challenging. Each renewable energy source has different inherent characteristics that, if appropriately used in the generation mix, could complement each other and create many technical and economic benefits for the power system. Usually, renewable energy resource complementarity studies are carried out with the objectives of smooth effect, reducing the need for storage and load tracking. In this study, the economic complementarity approach is introduced with the help of a Mixed integer nonlinear programming (MINLP) model. This approach can integrate renewable and storage energy sources with the grid and determine the optimal capacity of these resources in complementary used mode. The results show that the proposed method always imposes the system's lowest annual operation and investment costs.</jats:p>

Anup Shukla, Sri Niwas Singh

IET Renewable Power Generation • 2016

<jats:p>During the last few years, greenhouse gas emission especially from electric power generation is a major concern due to the global warming and environmental change, therefore, committing the generating units on minimum cost criterion is shifting toward minimising the cost with minimum emission. Due to the conflicting nature of economic and emission objectives, the generation scheduling becomes a multi‐objective problem. In this study, a weighted sum method is applied to convert multi‐objective problem to a single‐objective problem by linear combination of different objectives as a weighted sum and an efficient hybrid algorithm is presented for aiding unit commitment (UC) decisions in such environments. Due to uncertainty of wind power generation, the UC problem has become complex. To handle uncertainty, scenario generation and reduction techniques are used. The proposed hybrid approach is a combination of weighted improved crazy particle swarm optimisation with pseudo code algorithm, which is enhanced by extended priority list to handle the spinning reserve constraints and a heuristic search algorithm to handle minimum up/down time constraints. Simulation results confirm the potential and effectiveness of proposed approach after comparison with other methods reported in the literature.</jats:p>

Seifeddine Abdelkader Belfedhal, EL Madjid Berkouk, Youcef Messlem

Journal of Renewable and Sustainable Energy • 2019

<jats:p>This paper proposes a DC-linked hybrid renewable energy system (HRES) connected to the grid through a three level neutral point clamped converter. The proposed structure consists of a wind generator (with Maximum Power Point Tracking (MPPT)), power limitation, and pitch control modes) with a flywheel energy storage system, a photovoltaic generator (MPPT and power limitation modes) with a battery, and a super-capacitor connected to each capacitor of the DC link of the three level converter. With the aim of managing the power flow between the HRES, the grid, and the variable load demand, we designed a power management strategy according to the global state of charge of the storage system, the weather conditions, and the load demand. In order to show the efficiency of the proposed structure and management algorithm, numerical simulation was performed using MATLAB/Simulink.</jats:p>

A. Ranjeeta Khare, B. Yogendra Kumar

Journal of Renewable and Sustainable Energy • 2015

<jats:p>Evolution in utility grid/electric grid from centralized control structures to decentralized control structures has been changed rapidly. Moreover this is because of increased usage of distributed renewable energy sources in utility grid. As a result this type of evolution necessitates new and advance concepts /methods in control structures of smart electric grid. Multi agent structures (MASs) are consequence of this requirement which is able to handle disturbances due to renewable energy sources, capacity to run in islanding mode, highly distributed nature of grid. Presently multi agent structures are the advancement of artificial intelligence. Agents facilitate a means to bridge the gap between humans and machines by means of interaction and intelligence. With the use of multi agent structures, optimization of control system and enhancement in reliability and intelligence may be realized. Main objective of the review is to give acquaintance of application of multiagent system in hybrid system so that in future it may form basis of multiagent system design with its pros and corns. Authors have discussed various aspects for development of multi-agent structures used in hybrid systems like system power control, optimization techniques with more emphasis on agent communication, agent platform, and MAS architecture. As agent platform and agent communication are the basis of any MAS construction. Proper selection of agent platform and agent communication decides easy and simple design of the MAS. Several aspects of MAS and its results are compared to provide global perspective of the state of the art.</jats:p>

Ali M. Eltamaly, Abdullrahman A. Al-Shamma'a

Journal of Renewable and Sustainable Energy • 2016

<jats:p>The configuration of hybrid energy systems has a great influence on the cost of generated energy from the system. This paper introduces a design, simulation, assessment, and selection of optimum autonomous hybrid renewable energy configuration out of three different configurations. The proposed hybrid system contains photovoltaic (PV), wind, diesel, and battery energy systems. A new computer program has been designed to simulate different configurations of hybrid energy systems. A genetics optimization smart technique using a genetic algorithm has been used to calculate the optimum sizing for each component at different configurations of the hybrid system for minimum cost and highest reliability. The optimum penetration ratio of renewable energy systems (PV and wind) will be selected according to the lowest price. Actual data for one remote site in Saudi Arabia has been used in the input data of this computer program. Sensitivity analysis has been carried out to show the conditions for selecting any configuration under study. The results obtained from this study can help researchers, designers, and decision makers to answer many open questions regarding the design and installations of hybrid renewable energy systems.</jats:p>

Avishkar Wanjari, Atharva D. Amale, Savita V. Chandpurkar et al.

Hybrid Renewable Energy Generator with IOT Monitoring • 2023

<jats:p>Solar power plants need to be monitored for efficient power output. This aids in when restoring optimum energy output from power generation while being on the lookout for concerns such as defective solar panels, damaged connections, and dust accumulation on panels that reduce performance. Here, we propose an automated Internet of Things-based system for monitoring solar and wind power that provides automatic power monitoring from anywhere over the Internet. This system automatically detects the solar panel's output and sends information via the internet to an IOT system. Here, we used an IOT platform to send energy-generating parameters to an IOT platform server via the Internet. IoT-based controllers are the key components of the framework. This will promote preventative assistance, identification of the cause, and a true inspection of the plant that can sustain ongoing assessment. Nowadays, the frameworks for sustainable energy sources are emerging as the best way to produce power. As technology advances, the cost of sustainable energy source equipment is decreasing overall, enabling large-scale solar-powered photovoltaic setups. We developed a model for the use of a practical IoT strategy to screen a sun-oriented evaluation of the performance of a solar and wind power system with open-source resources and tools like Arduino and Ubidots. A SaaS (Software as a Service) platform called Ubidots gives a web-based area for tracking the generating parameters. Ubidots offers all services at lower charges, saving you money on website planning and maintenance. We concentrated on creating a system that required the least amount of effort and had an easy-to-use interface so that regular people could install rooftop solar-powered plants and screens without relying on organisations that provide administrative support.</jats:p>

, Mei Zhang

International Journal of Renewable, Green, and Sustainable Energy • 0

<jats:p>This study presents a comprehensive dynamic performance analysis and simulation of a standalone hybrid renewable energy system (HRES) tailored for remote Chinese communities with limited access to the national grid. The proposed system integrates solar photovoltaic (PV), wind energy, and battery storage to ensure a reliable and sustainable electricity supply. Using HOMER and MATLAB/Simulink, various configurations were modeled to evaluate system behavior under fluctuating weather and load conditions. The results highlight the system’s ability to maintain voltage stability, improve energy reliability, and reduce greenhouse gas emissions. Sensitivity analyses demonstrate the adaptability of the HRES to diverse environmental scenarios and its economic feasibility compared to conventional diesel-based systems. This research provides valuable insights for policymakers and engineers aiming to implement clean energy solutions in rural and off-grid regions of China.</jats:p>

Om Krishan, Sathans Suhag

IET Renewable Power Generation • 2020

<jats:p>This study proposes a novel control strategy for a hybrid energy storage system (HESS), as a part of the grid‐independent hybrid renewable energy system (HRES) which comprises diverse renewable energy resources and HESS – combination of battery energy storage system (BESS) and supercapacitor energy storage system (SCESS). The proposed control strategy is implemented into two parts: in the first part, HESS controller is designed and implemented to maintain the active power balance among different constituents of HRES and regulate DC‐link voltage (<jats:italic>V</jats:italic><jats:sub>DC</jats:sub>) under surplus power mode and deficit power mode. The low‐frequency components of imbalance power are diverted to BESS while the high‐frequency components are diverted to SCESS while maintaining the state of charge (SoC) constraints of HESS thereby reducing stress on BESS. In the second part, inverter controller is designed and implemented to maintain AC voltage and frequency within limits in the events of perturbation. The proposed HESS along with its novel control strategy, as implemented in the HRES, is a new proposition in this study. The detailed model of HRES is simulated in MATLAB/Simulink and the results prove the efficacy of the control strategy. Further, hardware‐in‐loop real‐time simulation studies using OPAL‐RT real‐time simulator demonstrate the feasibility of hardware implementation of HRES with the proposed control strategy.</jats:p>

Prakash Kumar, Dheeraj Kumar Palwalia

Journal of Renewable Energy • 2015

<jats:p>Power extension of grid to isolated regions is associated with technical and economical issues. It has encouraged exploration and exploitation of decentralized power generation using renewable energy sources (RES). RES based power generation involves uncertain availability of power source round the clock. This problem has been overcome to certain extent by installing appropriate integrated energy storage unit (ESU). This paper presents technical review of hybrid wind and photovoltaic (PV) generation in standalone mode. Associated components like converters, storage unit, controllers, and optimization techniques affect overall generation. Wind and PV energy are readily available, omnipresent, and expected to contribute major future energy market. It can serve to overcome global warming problem arising due to emissions in fossil fuel based thermal generation units. This paper includes the study of progressive development of standalone renewable generation units based on wind and PV microgrids.</jats:p>

Rajeswari Ramachandran, Jeevitha Satheesh Kumar, Balasubramonian Madasamy et al.

IET Renewable Power Generation • 2021

<jats:title>Abstract</jats:title><jats:p>This paper proposes a hybrid moth flame optimization–generalized Hopfield neural network (MFO‐GHNN) optimized self‐adaptive fractional order proportional integral derivative (FOPID) controller for automatic load frequency control of multi‐area hybrid power system (HPS). The control problem is formulated with an objective function of area control error associated with unknown parameters such as <jats:italic>K</jats:italic><jats:sub>p</jats:sub><jats:italic>, K</jats:italic><jats:sub>i</jats:sub><jats:italic>, K</jats:italic><jats:sub>d</jats:sub><jats:italic>, λ</jats:italic> and <jats:italic>μ</jats:italic> of FOPID controller. The fractional order of differentiator and integrator terms, and the initial values of <jats:italic>K</jats:italic><jats:sub>p</jats:sub>, <jats:italic>K</jats:italic><jats:sub>i</jats:sub> and <jats:italic>K</jats:italic><jats:sub>d</jats:sub>, are drawn from MFO algorithm. Then, the <jats:italic>K</jats:italic><jats:sub>p</jats:sub>, <jats:italic>K</jats:italic><jats:sub>i</jats:sub> and <jats:italic>K</jats:italic><jats:sub>d</jats:sub> are fine‐tuned by solving the dynamic equations governing the behaviour of GHNN under system uncertainties. To test the practicability and effectiveness of the proposed controller, the multi‐area HPS is studied with uncertain change in load demand, system parameters, solar and wind power generation. The proposed method is modelled using MATLAB/Simulink. The results showed that the steady state and transient performance indices of proposed FOPID controller are significantly enhanced than the PID, MFO‐FOPID and GHNN‐PID controllers. In addition, the stability of non‐linear dynamic HPS is analysed using Matignon's theorem of stability. Further, the performance of controller is validated using real time digital simulator run in hardware‐in‐the loop environment.</jats:p>

J. Arends

Microbial Biotechnology • 2017

Microbial bioelectrochemical systems have been in the full spotlight for over a decade due to the promise of being a platform for sustainable electrical power generation from wastewaters. This promise has not yet been fulfilled, but the research on bioelectrochemical systems (BES) has received a tremendous boost (Schr€ oder, 2011; Arends and Verstraete, 2012). The field has diversified into exploring various configurations of BESs for energy production/storage, bioremediation/waste cleanup and bioproduction/electrofermentation, as a tool for fundamental research and for biosensor development (Schr€ oder et al., 2015). The fact that many bacteria, with Geobacter spp. as one of the model organisms, are (putatively) able to directly deposit electrons on an electrode (Koch and Harnisch, 2016) opens the possibility to translate biologically relevant environmental signals directly into an electrical current. This allows the creation of a low current, amperometric microbial bioelectrochemical sensor system, applicable in many environments. However, to come to practical applications of BES-based sensors, several issues need to be overcome. Amongst others, one can think of signal/response ratio, signal specificity i.e. minimizing interferences, measurement range, need for calibration, signal stability over time, use of pure cultures or mixed communities, mechanical stability, storage and shelf life of the sensor probe. The work by Estevez-Canales et al. (2017) as described in their recent manuscript makes a step forward in prolonging the shelf life and optimizing storage conditions of pre-colonized bioanodes. They have developed a method to colonize an anode with Geobacter sulfurreducens in a silica gel matrix embedded in a carbon felt electrode. The microorganisms remained alive within the silica matrix in which they were encapsulated, and their concentration did not change for a minimum of 4 days as assayed with fluorescence microscopy. Activity could be maintained over 18 days in a lactate-fed system as determined by the current response. Acetate pulse experiments indicated a fast response time, in the order of minutes, of the bacteria encapsulated in the silica matrix. Using pre-colonized electrodes which take ~1 h to produce (Estevez-Canales et al., 2017) and can be stored offers a great advantage over producing (in the order of days) and possibly storing electroactive biofilms. As the authors indicate, several issues remain to be addressed to develop storable microbial electrodes for fast, selective and reproducible recordings. For example, optimal storage conditions for these electrodes need to be determined. From the manuscript, it becomes clear that the electrodes were stored under favourable conditions for Geobacter sulfurreducens. However, the most extreme conditions for storing the encapsulated microorganisms, in terms of temperature, humidity, time without electron donor/acceptor and exposure to atmospheric oxygen (Lin et al., 2004) still need to be understood. It would be interesting to compare the durability of a precolonized electrode with an electroactive biofilm of the same dimensions with regard to their storage conditions but also regarding the mechanical strength of biocatalyst attachment. An intriguing follow-up question is the impact of invasion, or colonization, of the silica surface by other microorganisms on the performance of the electrodes with immobilized electroactive microorganisms. Generally, microbial bioelectrochemical sensors are envisioned to be used in ‘dirty’ environments such as (waste)waters, fermenters and anaerobic digesters (Yang et al., 2015). These environments are characterized by a very diverse microbial community of which several members might possibly be capable of colonizing the silica matrix and thus hinder analyte mass transfer towards the embedded sensing microorganisms. On a more positive note, interaction of environmental microorganisms with encapsulated microorganisms (not Received 28 November, 2016; accepted 8 December, 2016. *For correspondence. E-mail jan.arends@ugent.be; Tel. +32 (0)9 264 59 76; Fax +32 (0)9 264 62 48. Microbial Biotechnology (2018) 11(1), 20–21 doi:10.1111/1751-7915.12590 Funding information European Research Council.

A. Schievano, A. Goglio, C. Erckert et al.

• 2018

In a very near future, renewable electricity produced by photovoltaic and eolic is destined to be the cheapest form of energy. As these sources can’t be constant in time, new industrial research challenges have already been shifted to electricity storage from the grid. Here we present an innovative concept of electricity storage system, based on the field of bioelectrochemical systems. Electromethanogenesis is one of the most recent applications in this field, where methanogenic microorganisms of the Archaea domain can fix CO2 to methane, under electrical stimulation. In other words, electricity can be efficiently converted into CH4, i.e. one of the most commonly used fuels, territorially-distributed with a capillary grid in most EU-Countries. What is needed, to implement this process, is a relatively concentrated source of CO2 in an anaerobic acqueous environment. Currently in our society, huge concentrated streams of CO2 are released into the atmosphere every day from wastewater and waste treatment facilities, as well as from landfills. To treat sewage and organic waste, organic matter is degraded to inorganic carbon, mainly by microbial oxidation processes, which are strongly energy-intensive. In perspective, every wastewater treatment, anaerobic digestion, organic waste composting facility and controlled ladfill could be a key hotspot to transform excess grid electricity into biomethane, while treating waste with the same energy. Biomethane could be injected to the distribution grid and the waste-management facilities would become the interface between the two grids. To achieve this scenario, efforts in scaling up electromethanogenesis systems and new bioelectrodes materials (e.g. electro-active biochar) are needed. Here, we summarize some key steps in this field of research and the constraints that are to be overcome.

R. Muñoz-Aguilar, D. Molognoni, P. Bosch‐Jimenez et al.

Energies • 2018

This paper deals with the design, operation, modeling, and grid integration of bioelectrochemical systems (BES) for power-to-gas application, through an electromethanogenesis process. The paper objective is to show that BES-based power-to-gas energy storage is feasible on a large scale, showing a first approximation that goes from the BES design and operation to the electrical grid integration. It is the first study attempting to cover all aspects of a BES-based power-to-gas technology, on authors’ knowledge. Designed BES reactors were based on a modular architecture, suitable for a future scaling-up. They were operated in steady state for eight months, and continuously monitored in terms of power consumption, water treatment, and biomethane production, in order to obtain data for the following modeling activity. A black box linear model of the BES was computed by using least-square methods, and validated through comparison with collected experimental data. Afterwards, a BES stack was simulated through several series and parallel connections of reactors, in order to obtain higher power consumption and test the grid integration of a real application system. The renewable energy surplus and energy price variability were evaluated for the grid integration of the BES stack. The BES stack was then simulated as energy storage system during low energy price periods, and tested experimentally with a real time system.

D. Molognoni, P. Bosch‐Jimenez, Rubén Rodríguez-Alegre et al.

Frontiers in Energy Research • 2020

Bioelectrochemical power-to-gas represents a novel solution for electrical energy storage, currently under development. It allows storing renewable energy surplus in the form of methane (CH4), while treating wastewater, therefore bridging the electricity and natural gas (and wastewater) grids. The technology can be coupled with membrane contactors for carbon dioxide (CO2) capture, dissolving the CO2 in wastewater before feeding it to the bioelectrochemical system. This way, the integrated system can achieve simultaneous carbon capture and energy storage objectives, in the scenario of a wastewater treatment plant application. In this study, such technology was developed in a medium-scale prototype (32 L volume), which was operated for 400 days in different conditions of temperature, voltage and CO2 capture rate. The prototype achieved the highest CH4 production rate (147 ± 33 L m–3 d–1) at the lowest specific energy consumption (1.0 ± 0.3 kWh m–3 CH4) when operated at 25°C and applying a voltage of 0.7 V, while capturing and converting 22 L m–3 d–1 of CO2. The produced biogas was nearer to biomethane quality (CH4 > 90% v/v) when CO2 was not injected in the wastewater. Traces of hydrogen (H2) in the biogas, detectable during the periods of closed electrical circuit operation, indicated that hydrogenotrophic methanogenesis was taking place at the cathode. On the other hand, a relevant CH4 production during the periods of open electrical circuit operation confirmed the presence of acetoclastic methanogenic microorganisms in the microbial community, which was dominated by the archaeal genus Methanothrix (Euryarchaeota). Different operational taxonomic units belonging to the bacterial Synergistes phylum were found at the anode and the cathode, having a potential role in organic matter degradation and H2 production, respectively. In the panorama of methanation technologies currently available for power-to-gas, the performances of this bioelectrochemical prototype are not yet competitive, especially in terms of volumetric CH4 production rate and power density demand. However, the possibility to obtain a high-quality biogas (almost reaching biomethane quality standards) at a minimal energy consumption represents a potentially favorable business scenario for this technology.

M. Shahparasti, A. Rajaei, Andres Tarrasó et al.

Electronics • 2021

This paper presents a proposal for potential bioelectrochemical power to gas stations. It consists of a two-level voltage source converter interfacing the electrical grid on the AC side and an electromethanogenesis based bioelectrochemical system (EMG-BES) working as a stacked module on the DC side. The proposed system converts CO2 and electrical energy into methane, using wastewater as the additional chemical energy input. This energy storage system can contribute to dampening the variability of renewables in the electrical network, provide even flexibility and grid services by controlling the active and reactive power exchanged and is an interesting alternative technology in the market of energy storage for big energy applications. The big challenge for controlling this system lays in the fact that the DC bus voltage of the converter has to be changed in order to regulate the exchanged active power with the grid. This paper presents a cascade approach to control such a system by means of combining external control loops with fast inner loops. The outer power loop, with a proportional-integral (PI) controller with special limitation values and anti-windup capability, is used to generate DC bus voltage reference. An intermediate loop is used for DC bus voltage regulation and current reference generation. A new proportional resonant controller is used to track the current reference. The proposed scheme has been validated through real-time simulation in OPAL OP4510.

Necla Altın, R. G. Akay

Journal of Electrochemical Energy Conversion and Storage • 2023

This review article addresses microbial fuel cells (MFCs) as a renewable energy source. MFCs are bioelectrochemical systems that use exoelectrogenic bacterial communities under anaerobic conditions to convert chemical energy into electrical energy. These systems are attracting attention due to their potential to reduce overall energy consumption, produce zero carbon emissions, and exhibit high energy density. The rapid development of renewable energy sources has increased the potential for bioenergy, particularly MFCs, to become one of the most important energy sources of the future. In addition to energy production, MFCs show potential for bioremediation and efficient removal of various pollutants. While MFC technology currently has limited application at the laboratory level, it is expected to increase in commercial use in the near future and offers great potential in the areas of renewable energy and environmental sustainability. This review article focuses on the historical and ecological development of the components used in MFCs, examining in detail their evolution and use in MFCs for renewable energy production.

Eleftheria Sapountzaki, U. Rova, P. Christakopoulos et al.

ChemSusChem • 2023

The urgent need to reduce CO2 emissions has motivated the development of CO2 capture and utilization technologies. An emerging application is CO2 transformation into storage chemicals for clean energy carriers. Formic acid (FA), a valuable product of CO2 reduction, is an excellent hydrogen carrier. CO2 conversion to FA, followed by H2 release from FA, are conventionally chemically catalyzed. Biocatalysts offer a highly specific and less energy intensive alternative. CO2 conversion to formate is catalyzed by formate dehydrogenase (FDH), which usually requires a cofactor to function. Several FDHs have been incorporated in bioelectrochemical systems where formate is produced by the biocathode and the cofactor is electrochemically regenerated. H2 production from formate is also catalyzed by several microorganisms possessing either formate hydrogenlyase or hydrogen-dependent CO2 reductase complexes. Combination of these two processes can lead to a CO2-recycling cycle for H2 production, storage, and release with potentially lower environmental impact than conventional methods.

E. Sudirjo, C. Buisman, D. Strik

Frontiers in Microbiology • 2019

Marine sediment has a great potential to generate electricity with a bioelectrochemical system (BES) like the microbial fuel cell (MFC). In this study, we investigated the potential of marine sediment and activated carbon (AC) to generate and store electricity. Both internal and external energy supply was validated for storage behavior. Four types of anode electrode compositions were investigated. Two types were mixtures of different volumes of AC and Dutch Eastern Scheldt marine sediment (67% AC and 33% AC) and the others two were 100% AC or 100% marine sediment based. Each composition was duplicated. Operating these BES’s under MFC mode with solely marine sediment as the anode electron donor resulted in the creation of a bio-battery. The recharge time of such bio-battery does depend on the fuel content and its usage. The results show that by usage of marine sediment and AC electricity was generated and stored. The 100% AC and the 67% AC mixed with marine sediment electrode were over long term potentiostatic controlled at -100 mV vs. Ag/AgCl which resulted in a cathodic current and an applied voltage. After switching back to the MFC operation mode at 1000 Ω external load, the electrode turned into an anode and electricity was generated. This supports the hypothesis that external supply electrical energy was recovered via bi-directional electron transfer. With open cell voltage experiments these AC marine bioanodes showed internal supplied electric charge storage up to 100 mC at short self-charging times (10 and 60 s) and up to 2.4°C (3,666 C/m3 anode) at long charging time (1 h). Using a hypothetical cell voltage of 0.2 V, this value represents an internal electrical storage density of 0.3 mWh/kg AC marine anode. Furthermore it was remarkable that the BES with 100% marine sediment based electrode also acted like a capacitor similar to the charge storage behaviors of the AC based bioanodes with a maximum volumetric storage of 1,373 C/m3 anode. These insights give opportunities to apply such BES systems as e.g., ex situ bio-battery to store and use electricity for off-grid purpose in remote areas.

P. D. Kolubah, H. Mohamed, Ananda Rao Hari et al.

Small • 2024

MXenes have excellent properties as electrode materials in energy storage devices or fuel cells. In bioelectrochemical systems (for wastewater treatment and energy harvesting), MXenes can have antimicrobial characteristics in some conditions. Here, different intercalation and delamination approaches to obtain Ti3C2Tx MXene flakes with different terminal groups and lateral dimensions are comprehensively investigated. The effect of these properties on the energy harvesting performance from wastewater is then assessed. Regardless of the utilized intercalant molecules, MXene flakes obtained using soft delamination approaches are much larger (up to 10 µm) than those obtained using mechanical delamination methods (<1.5 nm), with a relatively higher content of ─O/─OH surface terminations. When employed in microbial fuel cells, electrodes made of these large MXene flakes have demonstrated a power density of over 400% higher than smaller MXene flakes, thanks to their lower charge transfer resistance (0.38 Ω). These findings highlight the crucial role of selecting appropriate intercalation and delamination methods when synthesizing MXenes for bioelectrochemical applications.

S. Molenaar, A. Mol, T. Sleutels et al.

Environmental Science &amp; Technology Letters • 2016

Bioelectrochemical systems hold potential for both conversion of electricity into chemicals through microbial electrosynthesis (MES) and the provision of electrical power by oxidation of organics using microbial fuel cells (MFCs). This study provides a proof of concept for a microbial rechargeable battery (MRB) allowing storage of electricity by combining MES and a MFC in one system. Hexacyanoferrate(II/III) was used as counter redox couple. Duplicate runs showed stable performance over 15 days, with acetate being the main energy carrier. An energy density of around 0.1 kWh/m3 (normalized to anode electrolyte volume) was achieved at a full cycle energy efficiency of 30–40%, with a nominal power output during discharge of 190 W/m3 (normalized to anode volume). With this study, we show a new potential application area for bioelectrochemical systems as a future local energy storage device.

S. Molenaar, M. Elzinga, Sonja G. Willemse et al.

ChemElectroChem • 2019

Recently, the microbial rechargeable battery (MRB) has been proposed as a potentially sustainable and low-cost electrical energy storage technology. In the MRB, bioelectrochemical CO 2 reduction and subsequent product oxidation has successfully been combined in one integrated system. However, finding a suitable counter electrode is hindering its further development. In this work, we have tested two alternative counter electrodes in duplicate-namely, i) oxygen/water and ii) a capacitive electrode-for use in the MRB platform. During daily charge/discharge cycling over periods of 11 to 15 days, experimentally obtained energy efficiencies of 25 and 3.7 % were reported when using the capacitive and the oxygen/water electrodes, respectively. Large overpotentials, resulting in a voltage efficiency of 15 % and oxygen crossover leading to coulombic efficiencies of 25 % caused the considerably lower efficiency for the oxygen/water systems, despite the theoretical higher voltage efficiency. Although the capacitive electrode equipped systems performed better, energy density is limited by the operational potential window within which capacitive systems can operate reliably. Microbial community analysis revealed dominant presence of Geobacter in the bioanode and Selenomonadales in the biocathode. These results do not necessarily bring practical application of the MRB closer, but they do provide new insights in the working principle of this new technology.

A. Dhar, Nadavala Siva Kumar, Mehul Khimani et al.

International Journal of Energy Research • 2019

Naturally available neem tree gum consisting of bioelectrolyte and bioelectrode was fabricated for flexible energy storage device. Structural morphology, thermal stability, porosity and surface area of as prepared bioelectrode were characterized thoroughly by using scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller (BET) isotherm respectively. The bioelectrolyte conductivity was optimized under various concentrations of lithium ion salts and temperatures through electrochemical impedance spectroscopy (EIS). A flexible supercapacitor (SCs) was fabricated by using bioelectrodes and electrolyte and tested for its electrochemical properties. The supercapacitor displayed specific capacitance of 640 Fg‐1 and 200 Fg‐1 at a current density 0.5 Ag‐1 and 1.0 V operating potential window. The energy device has also demonstrated large operational window (2.0 V) and shown 102 Fg‐1 at a current density of 1.0 Ag‐1. The novelty of the present work lies in the simplified, cost‐effective procedure for preparation of biomaterials, their remarkably high stability under strong mechanical bent and long‐term charging‐discharging cycles of the fabricated device.

J. Mathew, A. Inobeme, Y. Azeh et al.

Caliphate Journal of Science and Technology • 2024

The urgent need to mitigate climate change has spurred innovative research in carbon capture and storage (CCS) technologies.  Electrochemical approaches utilize electrocatalysis and electrochemical reduction to capture carbon dioxide (CO2) from industrial  emissions, demonstrating high selectivity and enabling the production of valuable chemicals and fuels from captured CO2.  Bioelectrochemical techniques leverage microorganisms to convert CO2 into biomass or biofuels, enhancing carbon capture efficiency through biological and electrochemical synergy. Integrating bioelectrochemical systems with renewable energy sources provides a carbon-negative pathway, aiding industry decarbonization. This review underscores the transformative potential of these techniques in revolutionizing CCS strategies, emphasizing their role in addressing climate change while fostering a sustainable, circular economy. 

Mustafa Erguvan, Roohany Mahmud, David W. MacPhee

Energy Storage • 2020

<jats:title>Abstract</jats:title><jats:p>Electricity production from concentrated solar power (CSP) plants has been more commonplace in the last decade since the sun is one of the most abundant, renewable energy sources. The heat transfer fluid temperature in a CSP plant may go up to 1000°C; however, most of the current power plants operate on temperature ranges between 220°C and 565°C due to decomposition of molten salts in high temperatures. Since the sun is not available at nights and cloudy days, an important consideration is how to store the energy received by the sun to use at other times. In this study, a three‐dimensional borehole heat exchanger model is developed to store solar energy underground using concrete and molten salt as a storage medium and heat transfer fluid, respectively. While molten salt is circulating through a pipe, which is placed into the concrete, heat is transferred from the molten salt to the concrete or vice versa during the charging and discharging processes. Numerous simulations are conducted using ANSYS Fluent, with varying borehole diameters, mass flow rates, and thermal resistances of the borehole wall. Average concrete temperature, outlet heat transfer fluid temperature, and energy and exergy efficiencies are investigated for each case. It was found here that while concrete temperature increases with increasing mass flow rate, the increasing trend is minimal after the mass flow rate increases beyond 6 kg/s. There exists a negative relation between the borehole diameter and average concrete temperature during the charging process, and vice versa in discharging. Energy and exergy efficiencies varied from 0.2% to 98.1% and 0.1% to 77.9%, respectively. While the most efficient system was found at a borehole diameter of 550 mm for adiabatic cases, it was found to be 750 mm when heat leakage is taken into consideration. Borehole diameters of 2000 mm performed the worst among all cases due to low heat transfer rates. Heat leakage was found to have a significant impact on energy and exergy efficiencies, especially in energy efficiencies for higher borehole diameters and low mass flow rates in the discharging process.</jats:p>

Alberto Boretti

Energy Storage • 2022

<jats:title>Abstract</jats:title><jats:p>A renewable energy‐only grid must couple mutable energy supplies such as wind and solar photovoltaic and affordable energy storage by lithium‐ion batteries to dispatchable energy supply such as Concentrated Solar Power (CSP) with thermal energy storage (TES) and Enhanced Geothermal Energy (EGS). EGS is centered on the exploitation of the substantial unconventional geothermal energy supplies in the crust of the Earth which is missing permeability and groundwater, with significant opportunities in western Saudi Arabia where the solar resource is also relevant. Regarding conventional geothermal energy, thermal efficiencies of the cycles can be increased to above 30% with EGS, and above 40% through the integration of EGS with CSP and TES, surpassing the 50% efficiency mark adopting advanced ultra‐supercritical (AUSC) technologies.</jats:p>