Fengning Yang

Abstract:

This paper discusses sustainable renewable energy policies. The method used in this paper is a descriptive method that collects data from various sources literature studies and previous research. The results of the literature review show that the development of renewable energy in the European Union has three clusters dividing the share of renewable energy and the degree of dependency on energy imports based on the country. In Pakistan, the government has been designing a renewable energy policy since 2006 to supply sustainable energy to all consumers. In Nigeria, the electricity crisis and the need to reduce greenhouse gases spurred the development of renewable energy. Denmark has moved to wind power sources by increasing the share of renewable energy in the domestic electricity supply. The government encourages local ownership in the renewable energy sector, and many neighborhoods are connected to district heating systems that use renewable energy such as biomass. Increased investment in renewable energy technology will aid in addressing global energy concerns and hastening the transition to a low-carbon economy.Tulisan ini membahas tentang kebijakan energi terbarukan berkelanjutan. Metode yang digunakan dalam tulisan ini adalah metode deskriptif yang mengumpulkan data dari berbagai sumber dan studi literatur serta penelitian terdahulu. Hasil dari tinjauan literatur menunjukkan bahwa perkembangan energi terbarukan di Uni Eropa memiliki tiga kluster yang membagi negara-negara berdasarkan pangsa energi terbarukan dan tingkat ketergantungan impor energi. Di Pakistan, pemerintah telah merancang kebijakan energi terbarukan sejak tahun 2006 untuk memasok energi berkelanjutan kepada semua konsumen. Di Nigeria, krisis listrik dan kebutuhan untuk mengurangi gas rumah kaca memacu pengembangan energi terbarukan. Meskipun Nigeria memiliki potensi energi terbarukan yang besar, perkembangannya masih lambat. Diperlukan upaya lebih lanjut untuk meningkatkan pemanfaatan energi terbarukan melalui perjanjian kemitraan swasta, investasi dalam penelitian dan pengembangan, dan kebijakan berorientasi pasar.  Denmark telah melakukan peralihan ke sumber energi terbarukan dengan meningkatkan pangsa energi terbarukan dalam pasokan listrik domestik. Tenaga angin menjadi salah satu komponen utama energi terbarukan di Denmark. Pemerintah mendukung kepemilikan lokal dalam sektor energi terbarukan, dan sejumlah besar rumah tangga terhubung ke pemanas distrik yang menggunakan energi terbarukan seperti biomassa. Investasi yang lebih besar dalam teknologi energi terbarukan akan membantu mengatasi tantangan energi global dan mempercepat transisi ke ekonomi rendah karbon yang berkelanjutan

Abstract:

Direct bandgap perovskite and indirect bandgap Si, which form the two active layers in a tandem solar cell configuration, have different optoelectronic properties and thicknesses. The charge-carrier dynamics of the two-terminal perovskite-on-Si tandem solar cell in response to a supercontinuum light pulse is studied using transient photocurrent (TPC) measurements. Spectral dependence of TPC lifetime is observed and can be classified into two distinct timescales based on their respective carrier generation regions. The faster timescale (∼500 ns) corresponding to the spectral window (300-750 nm) represents the top-perovskite sub-cell, while the slower timescale regime of ∼25 μs corresponds to the bottom-Si sub-cell (>700 nm). Additionally, under light-bias conditions, the transient carrier dynamics of the perovskite sub-cell is observed to be coupled with that of the Si sub-cell. A sharp crossover from the fast-response to a slow-response of the device as a function of the light-bias intensity is observed. These results along with a model based on transfer matrix formulation highlight the role of charge-carrier dynamics in accessing higher efficiencies in tandem solar cells. The carrier transit times and lifetimes in addition to their optical properties need to be taken into account for optimizing the performance.

Abstract:

Water electrolysis is promising for industrial hydrogen production to achieve a sustainable and green hydrogen economy, but the high cost of the technology limits its market share. Developing efficient yet economic electrocatalysts is crucial to decrease the cost of electricity and electrolytic cell. Meanwhile, electrolysis in seawater electrolyte can further reduce feedstock cost. Here, a type of electrocatalyst is synthesized, where trace precious metals are strongly anchored on a corrosion-resistive matrix. As an example, the produced Pt/Ni-Mo electrocatalyst only needs an overpotential of 113 mV to reach an ultrahigh current density of 2000 mA cm⁻² in the saline-alkaline electrolyte, demonstrating the best performance reported thus far. It shows high activity and long durability in various electrolytes and under harsh conditions, including strong alkaline and simulated seawater electrolytes, and under elevated temperatures up to 80 °C. This electrocatalyst is produced on a large scale at a low cost and shows good performance in a commercial membrane electrode assembly stack, demonstrating its feasibility for practical water electrolysis.