Abstract

With the advent of the digital economy era, data centers are developing rapidly, and energy consumption has become a key factor in their high operating costs. Due to the explosive growth of servers, data centers require more and more power, resulting in power shortages and significant carbon emissions. Using renewable energy to power data centers is a promising solution. In this paper, we compared the performance differences of a hybrid renewable energy system using two different supplemental power sources, natural gas,and conventional diesel, to power a data center. Based on the power required by the data center and the supply of different energy sources, simulations are performed to obtain the system penetration capacity, economic costs, and carbon emissions for comparative analysis.The results show that the system has lower carbon emissions and cost in the natural gas mode, however, the penetration capacity is the same in both modes. With the same battery capacity of 3,000 kWh, the natural gas model costs 0.05 $/kWh less than the diesel model and reduces carbon emissions by 600 tCO2.

Abstract

The resilience of urban energy system is important to resist more frequent disasters under climate change. This paper aims to reveal the benefits of utilizing Electric Vehicles (EVs) as a source of energy to restore power supply under typhoon disasters. Firstly, we model the spatio- temporal EVs’ State Of Charge (SOC) distributed in Vehicle to Grid (V2G) stations through exploring the spatio-temporal trajectory paradigm of EVs and calculating on-road power consumption of EVs. Then, we proposed the post-typhoon-disaster power restoration strategy with V2G participation. Finally, we simulated the failure scenario of an urban power system under the typhoon disaster to verify the superiority of V2G in resilience improvement. The results show that using V2G can help avoid outages and help reduce load shedding.

Abstract

The growing share of renewable energy sources drives the need for increased flexibility in the energy systems. The flexibility provision from thermal plants is limited by the boiler’s thermal inertia as a bottleneck. Advanced controllers, such as model predictive control (MPC), have been identified as potential flexibility enablers. Fuel properties are crucial input for controllers. This work investigated the feasibility of using the properties obtained online by using near infrared spectroscopy based soft sensor to further improve the control performance. The performance of the existing proportional integral (PI) controller is compared with those of 2 feed forward (FF) MPC controllers. Both FF MPCs have significant improvement compared to PI controller and the FF MPC based on the full elemental composition shows the best performance due to more complete fuel information. There is a potential for revenues improvement with advanced control up to 1050 euros for one operation day.

Abstract

A new solar-wind-fuel complementary distributed energy system (DES) is proposed, which is integrated with solar-fuel thermochemical conversion for efficient utilization of solar and wind energy. To address the source-load mismatch caused by intermittent and unstable solar and wind energy, a new multi-energy system consisting of solar, wind and fuel is proposed to maintain the energy supply, with the consideration of the characteristics of day-night and seasonal complementation of solar and wind energy. Through solar-driven methanol decomposition, solar energy is upgraded to high-quality chemical energy in the form of syngas for storage. The results show that the new DES can promote the integrated use of wind and solar energy, increase the proportion of renewable energy in the system and reduce CO2 emissions. Compared to conventional power grid and fuel direct combustion, the new DES achieves a 42.12% reduction in CO2 emission.

Abstract

Crude oil is a major source of energy across the globe due to its diverse product derivatives for various industries and applications. However, the high CO2 emissions and energy requirements associated with its refining process threaten the goal of achieving carbon neutrality. The Crude Distillation Unit (CDU) has been identified as a major unit for CO2 emissions. Therefore, it is important to investigate the composition of feedstock (blended crude oil samples) fed to the CDU as a possible alternative to reducing CO2 emissions associated with refining. This study uses Aspen Hysys V12 with Aspen Energy Analyser to analyze different blended feedstock from six (6) different Nigerian crude oil; Brent, Bonga, Erha, Qua-Iboe, Usan, and Yoho. The result showed that Blend 1 had the highest CO2 emission linked to the high conversion of paraffin and naphthene to yield the highest Naphtha yield of 27.12 % compared to other blends. Blend 1 also had the highest CO2 emissions cost of $13.92 million/hr compared to $13.68 million/hr for Blend 7, with the lowest product yield. However, Blend 4 had the maximum heating energy requirement linked to its composition (mixtures of high medium and light crude ) which require more reactions to maximize yield. The result indicated that individual crude’s weight ratio in blended feedstock significantly increased Naphtha yield and affects CO2 emissions. Thus, blended feedstock composition will affect product yield, energy consumption, and CO2 emission due to the different compositions of individual crude. Therefore, to achieve the carbon neutrality goal, CO2 emission from individual crude oil needs to be investigated, develop a new model for optimum blending with fewer emissions and the CO2 emission cost should be added to blended feedstock price or individual crude cost to ensure a balance.

Abstract

Calcium looping process (CaL) is a promising alternative for realizing low-energy-penalty of post-combustion technologies. This study investigates the CO2 enrichment difference of three types of calcium looping heating supply methods: calcium looping combustion (CaLC), oxy-fuel combustion (CaL-Oxy), and Cu-based chemical looping combustion (CaL-CLC). and the three calcium looping processes are integrated with power plant to evaluate the energy efficiency and energy penalty of the power plants with CO2 capture based on these calcium processes. The results show that the CaL-CLC has the highest energy efficiency (39.4%) and the lowest energy penalty (3.46%), which indicates that reducing the gas separation cost plays important role caused by CO2 enrichment in the heat supplying method of calcium looping process.

Abstract

In order to reduce the frequency deviation and unit generation cost of an isolated microgrid, an adaptive load frequency control (ALFC) method is proposed in this paper. The method employs an adaptive proportional-integral-derivative (PID) controller to achieve adaptive control by adaptively adjusting the parameters of the controller to output the regulation command. In addition, to achieve adaptive regulation of the control parameters, a deep actor-critic (DAC) algorithm is proposed in this paper, which introduces multiple critics and Gaussian noise exploration techniques to enhance the quality of the ALFC strategy. The performance of the proposed method is tested in the Zhuzhou isolated microgrid of the China Southern Grid(CSG), which can effectively reduce frequency deviation and generation cost.

Abstract

Microwave has a significant promotion effect in gas-solid phase catalysis due to its unque advantages of heating process. This study introduces an innovative approach that combines microwave irradiation with a structured foam catalyst, Co3O4@S1/SiC, to enhance the isopropanol-to-propylene (ITP) process. The effectiveness of Co3O4@S1/SiC foam was investigated under various reaction temperatures (50-200 °C) and space velocities (1200 h-1), in comparison to Co3O4@S1/SiC pellets. The Co3O4@S1/SiC foam exhibited superior performance, achieving a higher selectivity towards propylene (approximately 99%) compared to Co3O4@S1/SiC pellets (93%). This enhancement can be attributed to improved mass and heat transfers facilitated by the foam structure. Co3O4@S1/SiC foam for ITP process has a milder condition with microwave irradiation (121 °C for 90% conversion) than conventional heating (184 °C for 90% conversion).

Abstract

Cu-based materials are effective electrocatalysts for converting carbon dioxide to ethylene. However, the hydrogen evolution reaction (HER) in aqueous solutions competes with the desired carbonaceous product, leading to poor selectivity. To overcome this issue, a PVDC coating was applied to a CuO electrode to regulate surface hydrophobicity, suppressing HER and promoting ethylene production. The influence of the PVDC layer on proton transfer and electrocatalyst stabilization was thoroughly investigated by varying the coating amount and order. The modified CuO electrode with a coating layer of only 50 µg/cm2 induced an optimal surface hydrophobicity (WCA=122°). It exhibited a highly efficient and selective ethylene production (FEC2H4=41.4%, |j|C2H4=6.8mA/cm2) and suppressed hydrogen evolution (FEH2=22.7%) at a low potential of -0.89V vs. RHE. The spent modified CuO electrode exhibited an increased presence of Cu+, facilitating the C-C coupling process. The stable hydrophobic properties and good electrical conductivity of PVDC-modified electrodes offer a simple and successful approach for advanced electrocatalyst development.

Abstract

Carbon neutrality roadmaps for cities in developing countries are completely different from those in developed countries due to historical, social, and economic limitations. Taking Shanghai as a case, this study proposes a new framework for sustainable net-zero carbon transition of cities in developing countries by integrating multiple purposes within multiple sectors under carbon budget constraints. The results show that 1) the total carbon emissions of Shanghai decreased from 2010 to 2020 in general, with a historic peak in 2011; 2) under the traditional trajectory, reaching the peak before 2030 is difficult; while under the carbon-neutral scenario, carbon peak will be achieved before 2025, and carbon neutrality can be achieved by 2050; 3) Great efforts are needed even in the process of peaking carbon emissions, especially in industrial sectors; 4) the integration of technology innovation and policy mechanisms is crucial to realizing zero carbon target. 5) This study provides improved understanding of urban carbon peaking and neutrality process from a systematic perspective, which could potentially help accelerate the sustainable transition towards carbon neutrality for cities that face dual challenges of development and decarbonization.