Dynamic programming with successive approximation and relaxation strategy for long-term joint power generation scheduling of large-scale hydropower station group

Energy ◽  
2021 ◽  
Vol 222 ◽  
pp. 119960
Author(s):  
Zhongzheng He ◽  
Chao Wang ◽  
Yongqiang Wang ◽  
Bowen Wei ◽  
Jianzhong Zhou ◽  
...  
Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3547
Author(s):  
Chung-Jen Chou ◽  
Shyh-Biau Jiang ◽  
Tse-Liang Yeh ◽  
Li-Duan Tsai ◽  
Ku-Yen Kang ◽  
...  

With regard to the best electro-chemical efficiency of an active direct methanol fuel cell (DMFC), the stacks and their balance of plant (BOP) are complex to build and operate. The yield of making the large-scale stacks is difficult to improve. Therefore, a portable power station made of multiple simpler planar type stack modules with only appropriate semi-active BOPs was developed. A planar stack and its miniature BOP components are integrated into a semi-active DMFC stack module for easy production, assembly, and operation. An improved energy management system is designed to control multiple DMFC stack modules in parallel to enhance its power-generation capacity and stability so that the portability, environmental tolerance, and long-term durability become comparable to that of the active systems. A prototype of the power station was tested for 3600 h in an actual outdoor environment through winter and summer. Its performance and maintenance events are analyzed to validate its stability and durability. Throughout the test, it maintained the daily average of 3.3 W power generation with peak output driving capability of 12 W suitable for Internet of Things (IoT) applications.


Author(s):  
David Chiaramonti ◽  
Anja Oasmaa ◽  
Yrjo¨ Solantausta

Biomass fast-pyrolysis oil (PO) is a liquid biofuel derived from lignocellulosic biomass: it offers several advantages compared to the direct us of solid bio fuels, such as high energy density, storability and transportability typical of liquid fuels, possibility to use the fuel in engines and turbines, easier downscaling of plants (which is a very important aspect for decentralized energy generation schemes). In addition, PO is the lowest cost biofuel, thus offering the possibility to penetrate also the large scale power generation market. Biomass POs have been studied and applications tested for many years, either for heat generation in medium-scale boilers or power generation. The present works reviews and analyses the most relevant experiences carried out so far and published results in power production from biomass PO. Power generation systems (PGS) which are here examined are gas turbines, diesel engines, stirling engines, as well as co-firing applications in large scale power plants (coal or natural gas plants). The main techniques for upgrading this biofuel and their impact on technologies are also shortly introduced and considered. The current status of development for each PO-based power generation option is discussed. This review work showed that long term demonstration (either technical or economical) is however still needed, even for the most developed technologies (use of PO in modified gas turbines and cofiring in natural gas stations): projects are on going to achieve long term demonstration.


Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2239
Author(s):  
Bin Luo ◽  
Shumin Miao ◽  
Chuntian Cheng ◽  
Yi Lei ◽  
Gang Chen ◽  
...  

The large-scale cascade hydropower plants in southwestern China now challenge a multi-market environment in the new round of electricity market reform. They not only have to supply the load for the local provincial market, but also need to deliver electricity to the central and eastern load centers in external markets, which makes the generation scheduling much more complicated, with a correlated uncertain market environment. Considering the uncertainty of prices and correlation between multiple markets, this paper has proposed a novel optimization model of long-term generation scheduling for cascade hydropower plants in multiple markets to seek for the maximization of overall benefits. The Copula function is introduced to describe the correlation of stochastic prices between multiple markets. The price scenarios that obey the Copula fitting function are then generated and further reduced by using a scenario reduction strategy that combines hierarchical clustering and inconsistent values. The proposed model is applied to perform the long-term generation scheduling for the Wu River cascade hydropower plants and achieves an increase of 106.93 million yuan of annual income compared with the conventional scheduling model, without considering price scenarios, showing better performance in effectiveness and robustness in multiple markets.


2020 ◽  
Author(s):  
ming xu ◽  
Hanlin Wang ◽  
Mingxian Liu ◽  
Jianning Zhao ◽  
Yuqiong Zhang ◽  
...  

Abstract With increasing demand of green energy supply with high efficiency and low CO2 emission, Solid oxide fuel cell (SOFC) has been intensively developed in recent years. And the integration of gasification with fuel cell (IGFC) shows potential in large scale power generation to further increase the system efficiency. Reliable design of multi-stacks for large system and long term stability of stacks with practical fuel gas from industrial equipment are the key for commercial application of IGFC. In this work, a test rig of 5kW SOFC system was fabricated using practical syngas from industrial gasifiers as fuel and long term test under high fuel utility was conducted to investigate the system performance. The results show that the maximum steady output power of system is 5700W for hydrogen case and 5660W for syngas case, and the maximum steady electrical efficiency is 61.24% while the fuel utility efficiency is 89.25%. The test lasted for more than 500h as the fuel utility efficiency was larger than 83%. The performances of each stack tower are almost identical at both initial stage and after long term operation. After 500h operation, the performances of stack towers just slight decrease under lower current and almost not change under higher current. Therefore, the results illustrate that the reliability of multi-stacks design and the prospect of SOFC power generation system for further enlarging its application in a MWth demonstration.


2020 ◽  
Author(s):  
ming xu ◽  
Hanlin Wang ◽  
Mingxian Liu ◽  
Jianning Zhao ◽  
Yuqiong Zhang ◽  
...  

Abstract With increasing demand of green energy supply with high efficiency and low CO2 emission, Solid oxide fuel cell (SOFC) has been intensively developed in recent years. And the integration of gasification with fuel cell (IGFC) shows potential in large scale power generation to further increase the system efficiency. Reliable design of multi-stacks for large system and long term stability of stacks with practical fuel gas from industrial equipment are the key for commercial application of IGFC. In this work, a test rig of 5kW SOFC system was fabricated using practical syngas from industrial gasifiers as fuel and long term test under high fuel utility was conducted to investigate the system performance. The results show that the maximum steady output power of system is 5700W for hydrogen case and 5660W for syngas case, and the maximum steady electrical efficiency is 61.24% while the fuel utility efficiency is 89.25%. The test lasted for more than 500h as the fuel utility efficiency was larger than 83%. The performances of each stack tower are almost identical at both initial stage and after long term operation. After 500h operation, the performances of stack towers just slight decrease under lower current and almost not change under higher current. Therefore, the results illustrate that the reliability of multi-stacks design and the prospect of SOFC power generation system for further enlarging its application in a MWth demonstration.


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