Full Spectrum Utilization Research Articles

(Digital Presentation) Photo-Thermo-Electrochemical Cells for on-Demand Solar Power and Hydrogen Generation

Converting solar energy into power and hydrogen provides a promising pathway to fulfilling instantaneous electricity demand (power generation) as well as continuous demand via storing energy in chemical bonds (hydrogen generation). Co-generation of power and hydrogen is of great interest due to its potential to overcome expensive electricity storage in conventional PV plus battery systems. Both solar thermochemistry processes and photo-electrochemical cells (PECs) are extensively explored technologies to produce solar hydrogen. The key challenges for solar thermochemistry processes are extremely high operating temperature (~ 1500 oC) and low demonstrated efficiency (< 1% for hydrogen generation). For PECs, the limited solar absorption together with sluggish electrochemical reactions, especially for OER, leads to limited theoretical solar fuel generation. Operating PECs at high temperature will lead to decreased photovoltage and interface stability. Inspired by the thermally regenerative batteries, we propose a photo-thermo-electrochemical (PTEC) device that uses the solid oxide-based moderate high temperature cell (~1000 ℃) as the photo-absorber for simultaneously converting concentrated solar radiation into heat and generating fuel or power electrochemically driven by the discharging power from the low temperature cell (~700 ℃). PTEC device enables full solar spectrum utilization, highly favorable thermodynamics and kinetics, and cost-effectiveness. A continuous PTEC device has two working modes, which are voltage differential (VD) mode and current differential (CD) mode. The current-voltage characteristics of a PTEC device are shown in Figure 1. It mainly consists of five parts. A high temperature cell (HTC) serves as a solar absorber and a low temperature cell (LTC) serves as heat recovery. Besides, the opposite electrochemical reactions take place in two cells meaning that HTC and LTC can also function as a hydrogen production as well as an electricity generator component, respectively. Heat exchanger(s) is placed between the HTC and LTC and hot fluids pass through a heat exchanger before entering LTC to reduce heat losses to environment as well as reducing input solar energy. The VD mode and CD mode can be realized in PTECs via controlling of DC-DC converter. In order to identify the main parameters, we develop a multi-physics model based on finite element method, including mass, heat and charge transfer, and electrochemical reactions. In addition, heat exchange is modeled by solving energy balance equation, DC-DC convertor is assumed by constant efficiency, and a lumped parameter model is used to describe solar receiver including energy losses of conduction and reradiation. This framework also allows us to provide design guidelines for PTEC devices with high solar-to-electricity (STE) efficiency and solar-to-hydrogen (STH) efficiency. The maximum STE and STH efficiency under reference conditions of PTEC device was found to be 4 % and 2 %. A further improved performance in terms of STE and STH efficiency are about 19 % and 16 %, respectively, via optimizing temperature configuration between HTC and LTC and material properties. It is also interesting to note that STH can reach higher than 80 % of STE at a large temperature difference, which shows a promising energy storage device by storing excessive electrical power in form of hydrogen. The main results show that the temperature of HTC and efficiency of heat exchange are key parameters to optimize PTEC efficiency. The performance of DC-DC convertor dominates STH efficiency. Besides, ionic conductivity of electrolyte can contribute to significantly expanding the operating current density range. The PTEC is a promising technology for solar energy conversion and storage as it is able to produce electricity and hydrogen in a single device. The solar conversion efficiency predicted with our numerical model supports that by optimizing the design and operational conditions, this technology can compete with existing solar fuel pathways. Figure 1

Selective Solar Harvesting Windows for Full-Spectrum Utilization.

Smart windows can selectively regulate excess solar radiation to reduce heating and cooling energy consumption in the built environment. However, the inevitable dissipation of ultraviolet and near‐infrared into waste heat results in inefficient solar utilization. Herein, a dual‐band selective solar harvesting (SSH) window is developed to realize full‐spectrum utilization. A transparent photovoltaic, converting ultraviolet into electricity, and a transparent solar absorber, converting near‐infrared into thermal energy, are integrated and coupled with a ventilation system to extract heat for indoor use. Compared with common transparent photovoltaics, the SSH window increases solar harvesting efficiency up to threefold while maintaining a considerable visible transmittance. Simulations suggest that the SSH window, besides generating electricity, delivers energy savings by over 30% higher than common smart windows. This is the first integration of transparent photovoltaic and transparent solar absorber into a window, which may open up a new avenue for the development of energy‐efficient buildings.

Solar-absorbing energy storage materials demonstrating superior solar-thermal conversion and solar-persistent luminescence conversion towards building thermal management and passive illumination

Nowadays, building energy consumption accounts for more than 50% of the total energy consumption. Exploiting advanced solar energy strategy is of great significance to achieve the building energy saving by spontaneously providing energy for a building. Herein, novel solar-absorbing energy storage materials constructed by solar-thermal conversion material, phase change material gel and persistent luminescence material are proposed to efficiently utilize the full spectrum of renewable solar energy towards the building thermal management and passive illumination. A flow chemical synthesis strategy is designed to continuously prepare the solar-thermal conversion material N, S-co-doped conjugated polybenzobisthiazole towards the robust solar energy harvesting (solar absorbance of 94.1%) and considerable thermal energy production (solar-thermal conversion efficiency of 88.3%). The liquid phase blending and sol–gel transition are proposed to fabricate the phase change material gels demonstrating high latent heat of 192.12 Jg−1 and self-supporting capacity, which can store the heat generated by N, S-co-doped conjugated polybenzobisthiazole and release the heat in the night. The persistent luminescence materials can absorb the ultraviolet–visible light in the solar spectrum in the daytime and emit the multicolour luminescence in the night. Taking advantages of the synergistic effect of the functional components, the proposed solar-absorbing energy storage materials demonstrate full spectrum utilization of solar energy (total solar absorbance of 91.93%) towards the building thermal management and passive illumination with a solar-light conversion efficiency of 1.65% and a solar-thermal conversion efficiency of 10.52%. The solar-absorbing energy storage materials create a state-of-the-art alternative for the next-generation energy saving buildings.

Design and experimental study of a Fresnel lens-based concentrated photovoltaic thermal system integrated with nanofluid spectral splitter

Minimizing optical losses during light focusing and preparing an appropriate nanofluid for spectral splitting is crucial for the performance of a concentrated photovoltaic thermal system. A Fresnel lens-based solar concentrator integrated with a nanofluid spectral splitting photovoltaic thermal system was designed and validated in this study. The design posited solar irradiation being appropriately concentrated by a linear Fresnel lens on a series of tubes through which the nanofluid flowed, allowing a large beam of limited spectra to be transmitted to the PV below, with the rest absorbed and converted to thermal energy is introduced. The optical loss was minimized by increasing the surface area and decreasing the optical path length. The synthesized nanofluid's spectral transmittance was measured experimentally. Dynamic modeling energy balance equation for the concentrated solar energy conversion system was developed and computed by MATLAB programming. Since the photovoltaic module was decoupled from the filtering channel and integrated with the water cooling, its surface temperature was much lower than the nanofluid and output water temperature. The combined efficiency of the system was 50.35%, 65.2%, 72.70%, 74.7%, and 85% for ZnO nanofluids with volume concentration ratios of 0.00036%, 0.00089%, 0.0017%, 0.0036%, and 0.0089%, respectively. A nanofluid with a concentration ratio of 0.00089 vol% provides the closest spectral match with a silicon solar cell, as verified by a reasonable electrical and thermal efficiency. We used this as a representative concentration ratio of ZnO nanoparticles to validate the prototype. The maximum deviation between simulated and experimentally determined overall performance was less than 3.7% which shows the two results are in good agreement. The findings highlight the potentials of employing a low-cost ZnO nanofluid in a concentrated photovoltaic thermal system for full spectrum utilization.

Thermodynamic evaluation of electricity and hydrogen cogeneration from solar energy and fossil fuels

A photovoltaics (PV) and methane-steam-reforming hybrid system for efficient and carbon–neutral electricity-hydrogen cogeneration from solar energy and fossil fuels is proposed. Middle-wavelength (x-870 nm) sunlight, suitable for PV conversion, is utilized for electricity generation by PV cells, while shorter- and longer-wavelength (280-x nm & 870–4000 nm) sunlight, which is not suitable for PV conversion, is rationally converted to thermal energy and further utilized for hydrogen production. Since electricity and hydrogen are both high-quality and clean energy carriers, the produced electricity and hydrogen could be directly output to users. The solar-to-product energy efficiency of the proposed system reaches 56.3%, 42.9% higher than that of the reference system (parallel arranged solar PVT part and solar methane-steam-reforming part). Efficiency improvement is mainly brought by full-spectrum utilization of sunlight and comprehensive utilization of electricity, thermal energy, and chemical energy. Besides, interconversion between hydrogen and electricity can be easily achieved via fuel cells or water electrolysis cells, which enables flexible supply of electricity and hydrogen on demand. When the proposed system only generates electricity, the solar-to-product efficiency is 30.2%, 29.1% higher than that of the reference system; when it only generates hydrogen, the solar-to-product efficiency is 54.5%, 44.5% higher than that of the reference system. In sum, this study offers an efficient, low carbon and flexible route for hydrogen-electricity cogeneration with solar energy and fossil fuels as inputs.

Experimental investigation of full solar spectrum utilization based on nanofluid spectral splitter for greenhouse applications

According to its application, solar spectrum can be divided into plant active spectrum (PAS) (300 ∼ 800 nm) and heat active spectrum (HAS) (800 ∼ 1500 nm). PAS is absorbed by plants for photosynthesis, and HAS will cause indoor high temperature when entering the greenhouse, which is unfavorable to plants. Nanofluid-based spectral splitter (NSS) is an effective way to improve the full-spectrum utilization of solar energy because of its superior performance of high transmittance in PAS and strong absorption in HAS. In this study, ATO-WO3/H2O nanofluids (NFs) are synthesized, in which the nanoparticles (NPs) are composed of 2.4 vol% ATO and 97.6 vol% WO3 (ATO-WO3). Physical property analysis shows that the NPs are well-dispersed in the fluid. The average transmittance of 0.005 vol% ATO-WO3 NFs with 10 mm optical path-length is 79.56% in PAS and 24.22% in HAS. The photothermal efficiency of NSS is related to the thickness and flow rate of NFs. The outdoor experimental results show that the total solar utilization efficiency of NSS is higher than 73% under the condition of 10 mm thick NFs layer and 100 L/h flow rate. Among them, the photothermal conversion efficiency is 34.4%, and the annual output power is 358.9 kWh/m2. Meanwhile, the light use efficiency is 39.2%, and the defined crop growth factor is 93.6%. In addition, the NSS system has a payback period of 0.76 years and a levelized cost of energy of 0.041 $/kWh within a 10-year life cycle. It shows that NSS greenhouse is feasible in technical and economic aspects. This study broadens the application of NFs in greenhouse and is an effective method to improve the full-spectrum utilization of solar energy.

Photothermally enabled MXene hydrogel membrane with integrated solar-driven evaporation and photodegradation for efficient water purification

Sustainable and energy-efficient water purification making use of solar energy is highly desirable to address water scarcity and pollution crisis. However, it remains a challenge to achieve full solar spectrum utilization with photothermal and photodegradation capability. Herein, inspired by the unique optical property of MXene, a novel assembly of MXene hydrogel membrane with synergistic photothermal and photocatalysis effect is proposed for integrated water purification. The MXene hydrogel membrane is fabricated based on the structure-directing of self-stacking MXene nanosheets and its abundant molecular interactions with the polymer matrix, polyvinyl alcohol (PVA), and the multifunctional layer-crosslinker, porphyrin. The obtained MXene hydrogel membrane exhibits fascinating physicochemical properties combining dynamic hydrophilic network of hydrogel and permeability of membrane, making it a preferred medium for both vapor generation and photodegradation. Moreover, calculation and experimental results illustrates the charge redistributions and coupling interactions between MXene and porphyrin, which imparts enhanced photothermal effect and photocatalytic activitiy. As a result, the MXene hydrogel membrane exhibits an high solar-driven water evaporation rate (1.82 kg m−2h−1) and a photodegradation efficiency (90.5 %), rendering an integrated water purification capability under one sun irradiation. This work presents a feasible and effective route towards develop of MXene-mediated cooperative photochemical and photothermal solar energy conversion for sustainable water purification.

Performance analysis of a hybrid photovoltaic-thermoelectric generator system using heat pipe as heat sink for synergistic production of electricity

The conventional tandem photovoltaic-thermoelectric generator (PV-TEG) system has proved the feasibility of solar full-spectrum utilization technology. Nevertheless, the inconsistent operating temperature range for PV and TEG impedes the development of this technique. Hence, to tackle the challenge of mismatch operating temperature issues, a developed bifacial PV-TEG system combined with flat plate heat pipe (FPHP) is proposed in this study. A 3D numerical model has been built to make a comparative analysis between the bifacial FPHP-PV-TEG system and the conventional tandem FPHP-PV-TEG system. The influences of solar concentration ratio, convective heat transfer coefficient, external load resistance, different working fluids on the output power and conversion efficiency are analyzed. The obtained results indicate that the comprehensive performance of the proposed bifacial FPHP-PV-TEG system is superior to that of the conventional tandem FPHP-PV-TEG system. An increase of 20.98% and 14.05% in overall power generation and energy conversion efficiency could be achieved in bifacial FPHP-PV-TEG system compared with tandem FPHP-PV-TEG system, when the solar concentration ratio is 6 and the convective heat transfer coefficient is 1200 W/m2/K. Moreover, the behavior of the two systems could be enhanced by increasing the solar concentration ratio and the convective heat transfer coefficient. Besides, using water as working medium exhibits the best performance followed by ethanol and acetone in the bifacial FPHP-PV-TEG system, while the variation of working medium in tandem FPHP-PV-TEG system could be almost neglected.

Division methods and selection principles for the ideal optical window of spectral beam splitting photovoltaic/thermal systems

Spectral beam splitting photovoltaic/thermal (SBS-PV/T) system has been attracting a lot of interest in its ability to achieve extremely efficient full-spectrum utilization of solar energy and co-generate electricity and thermal energy flexibly. The ideal optical window (IOW) is an essential concept in the SBS-PV/T system, splitting solar spectrum, and directly determining the ratio of electricity to thermal energy generated. In this work, 5 division methods (1, PV material bandgap division method; 2, Approximations of PV material spectral response method; 3, Spectral short-circuit current density method; 4, Optimal merit function method; 5, Optimal overall exergy efficiency method) for IOW have been reviewed and classified into three categories. Moreover, based on a 3-dimensional numerical model of the SBS-PV/T system, a systematic analysis and comparison of the aforementioned 3 types of methods were implemented under non-concentrated condition. Results showed that division method 2 is the best choice of IOW when considering system performance indicators, while division methods 4 and 5 are more suitable choices of IOW when considering thermal-economics. And, the divided bands of method 4 for Si solar cells show that energy balance model introduced comparatively big errors, the numerical modeling can predict IOW values of better accuracy. The IOW prediction results of the energy balance model introduced a maximum error of even 150 nm width. Substantially, the selection principles of different IOW division methods are provided, which is helpful for further development of SBS-PV/T systems.

Research on Performance and Optimization of PV- Thermoelectric (PV-TE) Building Integrated System Based on Full Spectrum Utilization of Solar Energy

After China's reform and opening up, China's economy is booming, the real estate once was an important pillar industry of China's economy, but with the progress of China's economy and construction engineering industry, the problem of energy consumption is becoming increasingly serious. Solar energy is a new type of automatic and resource-saving renewable energy. The application of solar energy technology is of great significance to building energy saving, but the application conditions are still not mature. Therefore, in order to make efficient use of solar energy, the project focuses on combining photovoltaic power generation technology, photothermal conversion technology and thermoelectric generator to design an efficient and low-cost PV-thermoelectric (PV-TE) building integrated system that can cope with a variety of harsh environments.

Wearable solar energy management based on visible solar thermal energy storage for full solar spectrum utilization

Efficient solar energy harvesting offers great potential for a global energy utilization beyond conventional fossil energy. However, current solar thermal approaches depend on sole molecular solar thermal energy storage (MOST) or photothermal materials (PTMs) by the rigid devices, leading to incomplete solar spectrum utilization and impossible wearability. Here we design the visible solar storage fabric (VSSF) with UV–Vis-NIR wavelengths utilization and wearable contrast photochromic display. This VSSF integrates the Azo-PCM@PS nanocapsule and Cs0.32WO3 nanoparticle, enabling the photochemistry thermophysics coupled energy storage and vis-NIR light harvesting, respectively. Rationally designed full solar spectrum utilization achieves high heat release (83 °C) energy efficiency of ∼4.8% under sunlight, which can protect human body from cold injury by a self-heating wrister. A photothermally-driven lifter based on VSSF is demonstrated to raise the targeted subject upon light triggering. Notably, the real-time energy state can be monitored by color change, in view of relationship establishment between color and energy density. This concept of wearable solar energy management provides the possibility of high solar energy efficiency by capturing sunlight through full solar spectrum.

Multi-objective optimization and exergoeconomic analysis for a novel full-spectrum solar-assisted methanol combined cooling, heating, and power system

A novel full-spectrum solar-assisted methanol combined cooling, heating, and power system was proposed. This system realizes the solar energy full-spectrum utilization in the hybrid solar energy device. A multi-objective optimization model with exergoeconomic analysis using energy-level based cost allocation was proposed to improve the comprehensive performance of the system. The heat storage ratio and supplemental heat ratio are defined to transfer the off-design annual operation conditions to the design parameters. The solar water heating area ratio as a structure variable of the hybrid solar energy device is optimized to improve the integrated performance of energy, economy and environment. The optimization results indicate that the comprehensive performance is best when the solar water heating area ratio is 0.5. Compared to the reference system, the unit exergy cost of total products increased by 49.0 %, whereas the primary energy is saved by 22.6 %, and the carbon dioxide is reduced by 70.6 %. The annual energy and exergy efficiencies are improved by 15.9 % and 17.3 %, respectively, and the collected solar energy is increased by 37.6 %. The sensitivity analysis demonstrates that the carbon dioxide emission, primary energy consumption, and unit exergy cost of total products are positively correlated with supplemental heat ratio and heat storage ratio.

Up-converted nitrogen-doped carbon quantum dots to accelerate charge transfer of dibismuth tetraoxide for enhanced full-spectrum photocatalytic activity

The charge carriers’ separation and the light harvesting ability are two key factors affecting the photocatalytic activity of photocatalysts. In this work, nitrogen-doped carbon quantum dots (N-CQDs) modified Bi2O4 (N-CQDs/Bi2O4) are fabricated via a facile hydrothermal method, which serve as efficient photocatalysts toward methyl orange (MO) degradation. The photocatalytic experimental results demonstrate that enhanced photocatalytic activities are acquired for all N-CQDs modified Bi2O4 composites. Moreover, 0.3 % N-CQDs/Bi2O4 exhibits the optimal photocatalytic activity with the reaction rate about 3.1-fold, 2.3-fold, and 2.9-fold of pure Bi2O4 under solar light, visible light, and near-infrared light irradiation. Such significantly increased photocatalytic performance can be ascribed to the following two advantages of N-CQDs: high conductivity that accelerate the separation of charge carriers and the upconversion behavior to enlarge light harvesting range. Additionally, the trapping experiments suggest that holes (h+) are of vital importance for the degradation process. This work paves the way for developing advanced photocatalyst with high charge separation efficiency and full-spectrum utilization.

Nanostructured Black Aluminum Prepared by Laser Direct Writing as a High-Performance Plasmonic Absorber for Photothermal/Electric Conversion.

Utilizing the abundant and renewable solar energy to address the global energy shortage and water scarcity is promising. Great effort has been devoted to photothermal conversion for its typically full-spectrum utilization and high efficiency. Here, the coral-like micro/nanostructure was fabricated on an aluminum sheet by a facile laser direct writing technology. The nanocluster and microscale branches of corals endowed this black aluminum with broad-band plasmonic absorption and rapid heat transfer from the light absorption region to substrate. The black aluminum achieved ultrahigh solar absorbance of over 92.6% (>95.1% in the visible range) and excellent light heating ability (>90.6 °C under 1.0 sun). With good photothermal properties, this plasmonic absorber was used in a state-of-the-art eight-layer membrane distillation system, producing a water yield of up to 2.40 kg m-2 h-1 and a high solar conversion efficiency of 166.5% under 1-sun irradiation. Photothermal electricity was also achieved based on this system with a thermoelectric generator, with a water yield of 0.89 kg m-2 h-1 and a maximum electrical power output of 7.21 μW cm-2 under 1.0 sun. Considering the excellent performance of the plasmon-enhanced black aluminum, this work provides an alternative and feasible route toward high-efficient utilization of the solar energy.

Recent Advances in Solar Energy Full Spectrum Conversion and Utilization

Recent Advances in Solar Energy Full Spectrum Conversion and Utilization

Strategic combination of ultra violet-visible-near infrared light active materials towards maximum utilization of full solar spectrum for photocatalytic chromium reduction

Maximum utilization of the full solar spectrum has been considered as a holy grail in the field of photocatalysis and has emerged important in the recent years, as the world needs to move towards renewable energy sources and also to maintain environmental health. In the search for a sustainable solution, we have come up with a strategic combination of materials, which can be active under all the three regions, namely ultraviolet (UV), visible and near infrared (NIR) of the sunlight. Specifically, we have developed a series of nanocomposites comprising of two dimensional nanosheets of zinc oxide (ZnO) and graphitic carbon nitride (GCN), and successfully coupled them with upconversion nanoparticles (UCNP). These nanocomposites have been successfully utilized for the photocatalytic chromium (Cr(VI)) reduction. The prepared nanocomposites exhibit an excellent photocatalytic activity toward reduction of Cr(VI) under different light region. A plausible mechanism for the photocatalytic process has been proposed based on the detailed study. This work is expected to pave way for the strategic design and development of many photocatalytic systems, which can utilize sunlight to the maximum extent.

Improved performance of quantum dot-sensitized solar cells by full-spectrum utilization

One of important factors for improving the power conversion efficiency (PCE) of quantum dot-sensitized solar cells is to enhance the utilization of sunlight. Herein, we modified the wavelength range of incident sunlight from the counter electrode (CE) side to investigate the photoelectric performance of solar cells. The effect of illuminating CuS and Cu2S CE with different light ranges (including non-illumination, UV–visible light, NIR light and full-spectrum light) on cell performance was investigated. It has been shown that illuminating from both sides of cell induce substantial increase in PCE, and a 42.8% enhancement in PCE compared with that irradiating from the photoanode side has been achieved with a champion PCE of 5.6% (Voc = 0.6 V, Jsc = 21.7 mA cm−2) based on CuS CE. This strategy focuses on the neglected problem of light utilization of the CE, and provides a direction for realizing full-spectrum absorption of liquid-junction solar cells.

Recent Progress in Interconnection Layer for Hybrid Photovoltaic Tandems.

Hybrid tandem solar cells offer the benefits of low cost and full solar spectrum utilization. Among the hybrid tandem structures explored to date, the most popular ones have four (simple stacking design) or two (terminal/tunneling layer addition design) terminal electrodes. Although the latter design is more cost-effective than the former, its widespread application is hindered by the difficulty of preparing an interface between two solar cell materials. The oldest approach to the in-series bonding of two or more bandgap solar cells relies on the introduction of a tunneling layer in multijunction III-V solar cells, but it has some limitations, e.g., the related materials/technologies are applicable only to III-V and certain other solar cells. Thus, alternative methods of realizing junction contacts based on the use of novel materials are highly sought after. Here, the strategies used to realize high-performance tandem cells are described, focusing on interface control in terms of bonding two or more solar cells for tandem approaches. The presented information is expected to aid the establishment of ideal methods of connecting two or more solar cells to obtain the highest performance for different solar cell choices with minimized energy loss through the interface.

Linearized analog photonic down-conversion link based on a dual-polarization quadrature phase-shift keying modulator

A novel linearized analog photonic down-conversion link based on an integrated dual-polarization quadrature phase-shift keying (DP-QPSK) modulator is proposed and experimentally verified. Radio frequency and local oscillator signals are fed into the DP-QPSK modulator via an electrical attenuator, respectively. By adjusting the ratio of the two attenuators, the third-order intermodulation distortion can be eliminated based on balanced detection. The scheme is simple and compact and it achieves full spectrum utilization because of using no filter. Experimental results show that the spurious free dynamic range is improved by 16.43 dB for a two-tone signal and the error vector magnitude is improved by 6.16% for a 100-MSym/s 16-quadrature-amplitude-modulation signal.

Efficient hydrogen production from solar energy and fossil fuel via water-electrolysis and methane-steam-reforming hybridization

A new concept of efficient and low-carbon hydrogen production via thermochemical and electrochemical hybrid route based on full-spectrum utilization of solar energy is proposed: sunlight with wavelength suitable for PV conversion is assigned to PV cells for electricity production, which drives water electrolysis for hydrogen production; the rest sunlight is assigned to thermal collectors and utilized for thermochemical hydrogen production. Based on this concept, a photovoltaic-electrolysis-methane-steam-reforming (PV-E-MSR) hybrid system for efficient and low-carbon hydrogen production is designed and analyzed. In the hybrid system, middle-wavelength (x-870 nm) sunlight is concentrated onto PV cells to generate electricity for water electrolysis and low-temperature heat (140 °C) for reactant preheating and vaporizing; the shorter- (280-x nm) and longer-wavelength (870–4000 nm) sunlight are concentrated onto MSR reactor to supply heat for MSR reaction. Thermodynamic analysis results show that solar-to-hydrogen efficiency and ratio of fossil-fuel energy in hydrogen of the hybrid system is higher to 54.6% and lower to 65.5%, respectively. Compared with a reference system composed of parallel-arranged solar MSR system and solar PV-E system, the hybrid system can generate 4.2% more hydrogen and save 3.8% fossil fuel, which benefits from full-spectrum optimized utilization of sunlight and complementarity between solar energy and fossil fuel. The concept and system proposed in this study might suggest a promising way for efficient and low-carbon hydrogen production from solar energy and fossil fuel.