Energy recovery from waste treatment and growing biomass is of great significance for the energy management and sustainable energy supply. It is shown that biomass and various wastes containing carbon are able to significantly contribute to the energy sector.

We describe a possible scenario for the energy development of an European country of the future. In addition to solar, wind, and hydrogen energy, priority should also be given to generating energy using small-sized gasifiers. First, it is sustainable energy since biomass and household waste are always available. Second, this approach will allow us to launch local electric power grids instead of the unified state and interstate grids, which will reduce up to three times the consumption of energy raw materials and financial resources. Third, a new design of electric motors, namely torus motors, will allow one almost halve electricity consumption and open a gateway to new technologies.

The need to achieve a uniform distribution of concentrated solar flux in the photovoltaic, thermal or any other receivers is a common problem; therefore, the optical characterization of the concentration system is necessary to determinate the physical characteristics of the receptors. In this work, a parabolic dish concentrator of 1.65x1.65 m2, developed by research from the University of Arizona, is optically characterized under normal operating conditions, also known as environmental conditions that refer to non-controlled conditions as solar radiation, environmental temperature and wind velocity that could affect slightly, by thermal and mechanical efforts, the distribution profiles of the concentrated solar radiation. The set used for the evaluation consisted of the parabolic mirror and Chilled Lambertian Flat Surface installed in the focal point on the optical axis of the mirror. The evaluation was divided into two parts: a theoretical part that consist on using ray tracing simulation and an experimental part that corresponds to image analysis. The used methodology in this work has been stablish in many researches, so this is a reliable method. The global optical error was 2.3 mrad under normal operating conditions.

Hydrogen is often touted as the fuel of the future, but hydrogen is already an important feedstock for the chemical industry. This review highlights current means for hydrogen production and use, and the importance of progressing R&D along key technologies and policies to drive a cost reduction in renewable hydrogen production and enable the transition of chemical manufacturing toward green hydrogen as a feedstock and fuel.

The chemical industry is at the core of what is considered a modern economy. It provides commodities and important materials, e.g., fertilizers, synthetic textiles, and drug precursors, supporting economies and more broadly our needs. The chemical sector is to become the major driver for oil production by 2030 as it entirely relies on sufficient oil supply. In this respect, renewable hydrogen has an important role to play beyond its use in the transport sector. Hydrogen not only has three times the energy density of natural gas and using hydrogen as a fuel could help decarbonize the entire chemical manufacturing, but also the use of green hydrogen as an essential reactant at the basis of many chemical products could facilitate the convergence toward virtuous circles. Enabling the production of green hydrogen at cost could not only enable new opportunities but also strengthen economies through a localized production and use of hydrogen. Herein, existing technologies for the production of renewable hydrogen including biomass and water electrolysis, and methods for the effective storage of hydrogen are reviewed with an emphasis on the need for mitigation strategies to enable such a transition.

Circular energy transformation of Turkey is essential to strengthen the national energy security. Turkey will benefit from moving towards a circular economy.

Circular economy (CE) has gained much attention due to global warming and climate change which are the most serious issues faced in the world. The United Nations has been struggling with the issues regarding sustainable development by releasing some programs and legislations, which are mostly supported by the EU. The EU's CE including both economy and energy within the scope of low-carbon world is binding for Turkey's energy transition. Among renewables, solar energy preserved the leading capacity expansion with an increase of 98 GW in 2019 in the world. Solar photovoltaic (PV) has become a mainstream energy source among renewables. Since the PV installation has been growing all around the world, several countries especially China, Germany, and the UK pay special attention to a sustainable PV waste management concept. We present the special case of Turkey within the global CE along with the current status of renewable energy in the global energy transformation. Turkey's energy outlook and the EU's targets are reviewed, and the significant role of solar energy in the CE transition process of Turkey has been revealed. We suggested adding a vision of “More Circular” to her new energy policy “More Domestic, More Renewable.”

For energy storage to be part of the transmission solution, storage developers need to work with transmission owners and follow the Regional Transmission Organization (RTO) transmission planning protocols.

Federal Energy Regulatory Commission (FERC) Order 841 mostly treats Electric Storage Resource (ESR) as a generation asset. To date, no FERC order lays out a path for treating energy storage as a transmission asset. One of FERC-jurisdictional RTOs – Midcontinent Independent System Operator (MISO) – has sent a “storage as a transmission-only asset” proposal to FERC, which FERC did not reject but did not approve either. This MISO filing begs the question – how to treat energy storage as a transmission project? The industry needs to understand how RTO cost allocation works for new and existing transmission projects. To appreciate cost allocation, stakeholders need to grasp the fundamentals of transmission project categories. Because to put together a business case for storage, modeling is essential. And modeling for reliability and economic projects vary. Getting into the weeds of transmission planning is what it takes to treat storage as a transmission asset.

Thermoelectric (TE) materials, or materials that can generate an electrical energy from temperature gradient, are promising for renewable energy technology. One fundamental aspect in the TE research is the demand to maximize the TE power-factor, PF = S2 σ, by having as large Seebeck coefficient (S) and electrical conductivity (σ) as possible. In the early 90s, Hicks and Dresselhaus proposed the PF enhancement by using low-dimensional materials, in which electrons are confined in certain directions and they move freely in the other directions. This quantum effect is known as the confinement length (L) effect, in which L is the thickness or diameter of the two-dimensional (2D) or one-dimensional materials, respectively. However, a key challenge is to understand the critical value of L, at which the PF can be significantly enhanced. Recently, we reevaluated the confinement theory of the low-dimensional materials to solve this issue. We showed that electrons are fully confined only when L is smaller than an intrinsic length Λ, the so-called thermal de Broglie wavelength, which depends on the materials and can be experimentally measured. Monolayer 2D materials naturally satisfy the condition of L < Λ since their confinement length is ∼ 1 nm, while their thermal de Broglie wavelength is ∼ 5-10 nm. Therefore, they could be a good candidate for TE materials. In this review article, we first review the TE materials with low dimensions. Then, we show the basic concept of the confinement effect and the consequence of such an effect. Finally, based on this effect, we turn our attention to the progress achieved recently in the TE properties of the 2D materials such as monolayer InSe, GaN electron gas, and SrTiO3 superlattices.

Placing a large storage project at one transmission node influences the transmission flows in the model. Hence, planners need an approach that estimates future storage services and logically places storage at multiple transmission nodes.

In planning models, it is hard to forecast which service storage might provide at any given hour because storage provides a wide variety of services such as capacity benefit, peaker replacement, reduction in renewable energy curtailment, and ancillary services. But transmission planning models are required to address North American Electric Reliability Corporation (NERC) reliability standards and criteria, with assumptions for planned additions of generation, transmission, and demand response resources. Hence, planners must assume a basic set of services for storage resources.

And this paper outlines a suggested approach to site storage resources in planning models by focusing on the generator interconnection queue for utility-scale storage and energy-intensive industries for commercial and industrial customers.

Partial shading of Cu(In,Ga)(Se,S)2 (CIGS) photovoltaic (PV) modules is getting more attention, as is witnessed by the increase in publications on this topic in recent years. This review will give an overview of shading tests executed on CIGS modules and focuses on the more fundamental aspects that are often studied on cells. Generally, CIGS modules display very attractive performance under predictable row-to-row shading. However, potential damage could occur under nonoptimal shading orientations: module output after shading tests could reduce due to the formation of local shunts, often called wormlike defects. The influence of many factors on the formation of these defects, including the internal currents and voltages and the shape and intensity of the shade, will be discussed. This review allows an increased insight in the degradation mechanisms caused by partial shading, which would ultimately lead to the introduction of more shade-tolerant CIGS PV products in the future.

Cadmium telluride (CdTe) is one of the leading photovoltaic technologies with a market share of around 5%. However, there still exist challenges to fabricate a rear contact for efficient transport of photogenerated holes. Here, etching effects of various iodine compounds including elemental iodine (I2), ammonium iodide (NH4I), mixture of elemental iodine and NH4I (I−/I3− etching), and formamidinium iodide were investigated. The treated CdTe surfaces were investigated using Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The CdTe devices were completed with or without treatments and tested under simulated AM1.5G solar spectrum to find photoconversion efficiency (PCE). Based on Raman spectra, XRD patterns, and surface morphology, it was shown that treatment with iodine compounds produced Te-rich surface on CdTe films, and temperature-dependent current–voltage characteristics showed reduced back barrier heights, which are essential for the formation of ohmic contact and reduce contact resistance. Based on current–voltage characteristics, the treatment enhanced open-circuit voltage (VOC) up to 841 mV, fill factor (FF) up to 78.2%, and PCE up to 14.0% compared with standard untreated CdTe devices (VOC ∼ 814 mV, FF ∼ 74%, and PCE ∼ 12.7%) with copper/gold back contact.

Wave energy converters have been developed and commercialized in past decades; they have now faced numerous challenges of large volume sizes, environmental hazards, and high costs of deployment, components and maintenance. To address these challenges and make a wave energy converter practically available for various applications at a reasonable cost, we have developed a soft wave energy harvester that integrated low-cost soft material structures and piezoelectric-based Macro Fiber Composite (MFC). This integrated soft wave energy converter has a straightforward fabrication process and structure that can harvest energy from a broad working frequency of waves. The innovative design combined low-cost and commercially available materials and formed a harvester that addressed the aforementioned problems of commercially available harvesters. Additionally, the low cost and simple design are scalable for large energy conversion in the future. The energy conversion performance of the proposed platform has been investigated in a wave flume with low-frequency incoming waves (<2Hz). The soft energy conversion platform is hung like a curtain and produces a maximum 487nW. Also, the low cost and durable encapsulation can protect the electrical properties of MFCs and circuits, and a single harvester can last through all experiment steps without any degradation, which was more than 170 hours.

Thermoelectric (TE) generators, converting waste heat to electricity regain their attractiveness for reduction of fossil fuels’ reliance, and consequently minimizing adverse environmental effects. Such generators are based on an electrical series connection of TE couples, which consist n- and p- type semiconducting legs divided by metallic bridges. While for intermediate temperatures of up to 500°C, n-type PbTe was extensively studied and employed in commercial TE power generation applications, its maximal efficiency, as was reflected by the TE figure of merit, ZT, was in most of the cases maximized at a narrow temperature range for any given donor dopant concentration. The most commonly applied donor dopants are iodine and bismuth. Yet, some interesting characteristics were recently proposed upon using Ti as a donor dopant. Up to date an impressive maximal ZT of ∼1.2 was obtained at 500°C, upon doping of PbTe by 0.1 at.% Ti, while no lower concentrations were ever investigated. In the current research a lower, 0.05 at.% Ti doping level was applied, leading to the highest ever reported ZT values, for any given Ti doped PbTe, up to 350°C. Since the chemical compatibility of Ti with PbTe, as a metallic bridge in such couples, is well established, mainly due to its low diffusion rates, the potential of generating a stable Ti-doped functionally graded n-type PbTe material, with enhanced TE performance, is currently being proposed.

We have developed new flexible dye-sensitized solar cells (DSSCs) comprising organic dye (JH-1), cobalt redox electrolyte and hierarchically structured TiO2 (HS-TiO2) photoelectrode prepared using an electrostatic spray method. The performance of JH-1 sensitized flexible DSSC with a cobalt redox electrolyte was compared with those of N719-based DSSC and DSSC with I-/ I3- redox electrolyte. As a result, JH-1 sensitized flexible DSSC with [Co(Ⅲ/Ⅱ)(bpy-pz)3](PF6)3/2 redox system exhibited a high photocurrent density of 9.17 mA cm-2, an open circuit voltage of 0.953 V, a fill factor of 0.70, and a power conversion efficiency of 6.12% under 1 sun illumination (100 mW cm-2). The incident photon-to-current conversion efficiency was measured to explain the photocurrent generation difference by different dyes and electrolytes. The electron recombination lifetime of cells was measured by intensity-modulated photovoltage spectroscopy. Mass transport in DSSCs employing cobalt redox electrolytes was also investigated by the photocurrent transient measurements and electrochemical impedance spectroscopy (EIS) analysis.

Two benzodifuran (BDF) polymers, PBDF-C and PBDF-S, with alkyl and alkylthio substituted thiophene side-chains and benzodithiophene-4,8-dione (BDD) as the acceptor were designed and synthesized. Their optical, electrochemical properties and photovoltaic performances were systematically investigated. The polymer solar cells (PSCs) with a device structure of ITO/PEDOT:PSS/polymer:PC71BM/Ca/Al were fabricated. The PBDF-C based device showed a power conversion efficiency (PCE) of 3.01% after adding 1 vol% 1,8-diodooctane (DIO) as the solvent additive, and PBDF-S gave an enhanced PCE of 3.48% without any post-treatments. The enhancements were from the higher open-circuit voltage (Voc) and fill factor (FF). The thermal- and solvent-treatment-free processing is more favourable for the large area roll-to-roll manufacturing or printing technology for PSCs.

High-rate lithium ion batteries with long cycling lives can provide electricity grid stabilization services in the presence of large fractions of intermittent generators, such as photovoltaics. Engineering for high rate and long cycle life requires an appropriate selection of materials for both electrode and electrolyte and an understanding of how these materials degrade with use. High-rate lithium ion batteries can also facilitate faster charging of electric vehicles and provide higher energy density alternatives to supercapacitors in mass transport applications.

High-rate lithium ion batteries can play a critical role in decarbonizing our energy systems both through their underpinning of the transition to use renewable energy resources, such as photovoltaics, and electrification of transport. Their ability to be rapidly and frequently charged and discharged can enable this energy storage technology to play a key role in stabilizing future low-carbon electricity networks which integrate large fractions of intermittent renewable energy generators. This decarbonizing transition will require lithium ion technology to provide increased power and longer cycle lives at reduced cost. Rate performance and cycle life are ultimately limited by the materials used and the kinetics associated with the charge transfer reactions and ionic and electronic conduction. We review material strategies for electrode materials and electrolytes that can facilitate high rates and long cycle lives and discuss the important issues of cost, resource availability and recycling.

The voltammetric hysteresis visible in current density versus solar cell potential (J-V) curves is a serious concern because it is known that the performance of Dye-sensitized Solar Cells (DSCs) depends on the direction of the potential and the rate of scan. J-V characteristics of gel electrolyte based DSCs were obtained by varying the scan rate from 0.01 to 0.1 V s-1 and the direction from forward bias to reverse bias and reverse bias to forward bias. Three electrolytes were tested, two of them were 100% single salt electrolytes of KI and Hex4NI, and the other was a mixed salt electrolyte containing KI (75%) and Hex4NI (25%). DSC containing mixed salts electrolyte exhibited higher efficiency than single salt electrolytes. The energy conversion efficiency with mixed salts increased from 5.9 to 6.4% with the increase of the scan rate from 0.01 to 0.1 V s-1, when the scanning was conducted from forward bias to reverse bias direction. However, when the scanning was carried out with revised polarity a drop of the efficiency was observed with increasing rate of potential scan. Present work emphasizes the importance of reporting the rate and direction of potential scan along with solar cell performance parameters.

Thermoelectric technology has key benefits and strengths in many terrestrial energy recovery applications. Thermoelectric system cost is a key factor governing final decisions on the use of thermoelectric energy recovery systems in all terrestrial applications; thus cost being just as important as power density or efficiency for the adoption of waste energy recovery (WER) thermoelectric generators (TEG). New integrated cost analysis / thermoelectric analysis approaches have now shown key relationships and interdependencies between overall TEG system costs, including TE material costs, manufacturing costs, and specifically heat exchanger costs; and the TE performance design metrics such as TE material properties, TE device design parameters, heat exchanger performance metrics such as hot-side and cold-side conductances and UA values, and hot side heat flux in achieving optimal TEG WER designs. These new approaches have led to a new thermoelectric system economics paradigm that strongly influences TEG cost and performance decisions. While prior work provided foundations for the latest cost scaling analysis / TE performance analysis, this new work offers new insights and understandings and provides the basis for new thermoelectric system economics. Optimum TEG system cost conditions can now be tied directly to the TE materials, TEG design parameters, and heat exchanger design parameters through critical non-dimensional analysis. The non-dimensional analysis and metrics show the TEG system cost and performance interdependencies and intercouplings in one unifying and cohesive relationship. Prior work by T.J. Hendricks, S.K. Yee, and S. LeBlanc, J of Electronic Mater, 45, (3), 1751-1761, 2015 has shown that the system design that minimizes cost (e.g., the G [$/W] value) can be close to designs that maximize power, but these design regimes are not necessarily aligned with high system conversion efficiency or high specific power. Key sensitivities and interrelationships between critical cost metrics and critical TE performance and design metrics in the new thermoelectric system economics paradigm are explored. Quantitative data showing these sensitivities and their implications on TEG system design in terrestrial WER applications are presented. Critical non-dimensional parameter mapping has shown where heat exchanger cost- dominated conditions, TE material or manufacturing cost-dominated conditions, and combinations of cost conditions control and drive the overall TEG cost and performance. This new cost-performance paradigm shows the required pathways and challenges to achieving TEG system costs of $1 -$3/Welec.

A systematic, objective approach for selecting the most suitable solar energy system in a large and diverse range of applications is presented. The definition of Levelized Energy Cost (LEC) is modified/extended, including a Societal Impact Factor (SIF). The use of the methodology is demonstrated for a specific case. The method can be used for selecting an optimal system configuration and for identifying research and development directions.

A systematic and objective approach for selecting the most suitable solar energy system for a large and diverse range of applications is presented. The main parts of the approach are:

(i) Define the project objectives and fundamental system design requirements.

(ii) Establish a reliable and objective method for determining and comparing energy costs.

(iii) Follow a well-defined methodology for obtaining a configuration that meets the system objectives and complies with all the design requirements, at a minimum energy cost.

These parts are divided into discrete steps, which emphasize meeting the project objective and design requirements. The definition of the main cost comparison metric, the Levelized Energy Cost (LEC), is modified to include the ratio between energy sold and energy production capacity, and a Societal Impact Factor (SIF) for health, environmental, societal, political and cultural aspects.

Application of the method is demonstrated for a specific case—a system whose objective is “providing an extensive and reliable supply of renewable energy, aiming to gradually replace most or all of the fossil fuel combustion in a highly populated region.”

As shown, the process can serve dual purposes, (i) finding the most suitable system configuration and (ii) pointing out vital research and development objectives. The suggested method is also applicable to complex energy conversion configurations, such as hybrid or symbiotic systems.

Self-powered smart systems utilizing the high voltages generated by triboelectric nanogenerators (TENGs) have been systematically reviewed, with several featured applications highlighted, including electrospray, optical device, microplasma, and microfluidic.

To provide a sustainable power solution for electronics, triboelectric nanogenerator (TENG) has been developed since 2012 for high-efficiency mechanical energy harvesting from the ambient environment. TENG has very unique output characteristics including high voltage and limited current density. Thus, it is challenging to directly power most of the commercial electronics in high efficiency. However, these features also bring opportunities for high-voltage applications. Here, we will review the efforts for developing TENG as a controllable high-voltage power source for various applications. The review article will start from fundamental studies about how the high-voltage output was generated, and then, several representative research in recent years will be reviewed, including electrospray, optical devices, microplasma, field emission, and electrically responsive materials. These studies will drive the further development of TENG technology for broad applications and industrializations toward high-efficiency self-powered systems.