Energy and Mass Matching Characteristics of the Heat-Absorbing Side of the Ammonia Energy Storage System under Nonuniform Energy Flow Density.

Ammonia thermochemical energy storage is based on a reversible reaction and realizes energy storage and utilization by absorbing and releasing heat. Under different energy flow densities, the efficiency of an ammonia reactor composed of multiple ammonia reaction tubes is different. Based on the coupling model of light, heat, and chemical energy of an ammonia decomposition reaction system, taking a 20 MW solar thermal power plant as the research object, this paper proposes a new model of ammonia energy storage system, which places the ammonia decomposition side in a low-pressure environment and the ammonia synthesis side in a high-pressure environment. The effects of different inlet temperatures, inlet flow rates, flow distribution, and energy flow density distribution on the ammonia energy storage system were studied. The results show that the increase of inlet temperature and the decrease of inlet flow rate are beneficial to the improvement of thermal efficiency and exergy efficiency of the system to a certain extent, but when the inlet temperature increases or the inlet flow rate decreases to a certain extent, the efficiency of the system will decline. Under the condition of nonuniform energy flow density and nonuniform inlet flow distribution, more ideal system thermal efficiency and exergy efficiency can be obtained.

A demonstration concentrating solar power plant in China: Carbon neutrality, energy renewability and policy perspectives.

Concentrating solar power (CSP) is considered as a promising renewable electricity source due to its superiority in providing dispatchable and base-load electricity. This study performs a systems process analysis to quantify the carbon emissions and nonrenewable energy costs induced by a state-of-art demonstration CSP plant located in the Tibetan plateau. Estimated to induce 111.2 g CO2 eq/kWh carbon emissions and 1.42 MJ/kWh non-renewable energy consumption, the CSP plant is considered to have extremely high carbon neutrality (88.8%) and energy renewability (86.4%). The prominent performance of carbon emissions reduction and energy conservation induced by the CSP plant shed light on its superiority of reliable power supply and environmental benefits. The plant is expected to cumulatively fulfill 3.4 million tons of carbon emissions reduction over its life cycle. In contrast to coal-based power and other renewable energy technologies, CSP technology is shown to be a promising solution to the low-carbon energy transition. Besides, a scenario analysis indicates that the incremental employment of CSP technologies will play a critical role in coping with climate change and energy security in China. Moreover, multiple policies to facilitate the development of the CSP system in China are elaborated, such as the promotion of integrated solar combined-cycle systems. The empirical finding draws a holistic picture of the carbon neutrality and energy sustainability performance of CSP technologies, and the systematic analysis in this study provides comprehensive policy perspectives for energy policy in the Tibetan region as well as in China in the context of global climate change.

Optimized Demand-Side Day-Ahead Generation Scheduling Model for a Wind-Photovoltaic-Energy Storage Hydrogen Production System.

This paper proposed an optimized day-ahead generation model involving hydrogen-load demand-side response, with an aim to make the operation of an integrated wind-photovoltaic-energy storage hydrogen production system more cost-efficient. Considering the time-of-use electricity pricing plan, demand for hydrogen load, and the intermittency of renewable energy, the model has the ambition to achieve minimum daily cost of operating a hydrogen production system. The model is power-balanced, fit for energy storage devices, and developed through adaptive simulated annealing particle swarm optimization. Analysis results showed that the proposed optimized scheduling model helped avoid the significant purchase of electric power at peak times and reduced the cost of running the hydrogen production system, ensuring that the daily hydrogen energy produced could meet the daily demand for the gas load. This justified how the model and its algorithm were correctly and efficiently applied.