【CASK EFFECT】0910F阅读全方位锻炼--越障【SCI】 1-17

tuziduiduiUID: 2599524

【CASK EFFECT】0910G阅读能力基础自测（速度、难度、深度、越障、真题、RAM）
https://bbs.gter.net/forum.php?mod=viewthread&tid=910464&highlight

【CASK EFFECT】0910F阅读全方位锻炼--越障【SCI】汇总贴
https://bbs.gter.net/thread-982020-1-1.html

规则：0 u, r. g$ C/ d+ [4 f5 C

我每天贴出1000字左右的一篇文字7 j) N0 Q, Q- ]( V4 E

没有别的要求，只要大家坚持读完就可以

如果你能坚持一个月，你会发现自己的阅读进化了~
[注]9 K7 C8 w4 {" L
1、直接在电脑屏幕面前做，虽然GRE阅读是在纸上考，但是这个过程会遏制你做笔记，同时给你的阅读造成视觉障碍，也就是把难度训练和抗干扰训练同步结合，增加效率（初期会很累，但是既然大家想要成为高手，那么就别对自己太温柔）

Today's Topic: System-level energy efficiency is the greatest barrier to development of the hydrogen economy

The hydrogen economy concept proposes hydrogen is an energy commodity like electricity or gasoline which individuals purchase to carry out their activities and supply energy services. Originally proposed in the early 1970s, the hydrogen economy postulated that hydrogen could be generated from a range of energy resources and distributed through transmission networks to provide energy services in a similar way as electricity is currently used (Bockris, 1972; Anon, 1973; Gregory, 1973; Rifkin, 2002). The hydrogen would be generated by renewable resources and stored, then converted back to electricity using fuel cells. The hydrogen transport system would function in much the same way as the current system, but would not require imported liquid fossil fuel, would not produce local air pollution and would have lower CO2 emissions.Although hydrogen is currently produced in significant quantities during petrochemical refining and reforming processes, it is primarily used directly as a chemical feedstock, for example in production of methanol and ammonia.These applications are not considered components of the hydrogen economy, asthe hydrogen is not used for providing an energy service.

The hydrogen economy concept has led to research investment in related sciences and in technology development projects including distributed power, combined heat and power, back-up power and fuel cell vehicles. The full manifestation of the hydrogen economy vision includes not only freedom from imported oil, but social liberation of consumers who will be empowered to create their own hydrogen at home from solar cells or cheap electricity, store their hydrogen, fuel their own vehicles and generate electricity for their homes. By producing and storing hydrogen locally, people would be able to power the grid at peak times (Vaitheeswaran, 2003).

Pursuit of the hydrogen economy is motivated by several critical issues, energy security and environmental impacts. Commonly cited benefits of using hydrogen gas as an energy commodity are listed below:
• Efficiency—fuel cells have higher theoretical conversion efficiency than internal combustion engines or power cycles.
• Flexibility—a range of renewable and non-renewable energy resources can be utilised for hydrogen production by electrolysis or reforming.
• Environmental—water is the only by-product of hydrogen conversion either by electrochemical reaction or combustion.
• Energy Storage—hydrogen produced by electrolysis from excess capacity in renewable electricity could be stored.
• Security of transport fuel—local energy resources would be used to produce hydrogen, thus reducing economic and political risks from imported oil.

The vision of a renewable, secure,non-polluting transport fuel is highly attractive in light of political issues and environmental concerns. Public interest, political support and high-profile industrial research involvement have resulted in government research funding in virtually every developed country.

New Zealand policy has been to support hydrogen and fuel cell research with the focus being on “early adoption” of technologies developed in other countries and delivered to the international market. Over the past 8 years, government research funding in this area has increased to just over 13% of the $14.6 million (NZD)energy-related expenditures (MORST, 2006 Ministry of Research Science and Technology (MORST), 2006. Energy Research, Road maps for Science, NZ.MORST, 2006). The research is mostly conducted at Crown Research Institutes (CRIs) and Crown Owned Enterprises, with some projects at universities (MED, 2005; IRL, 2005; FRST, 2008). Recent hydrogen projects include:
• Integration and testing of domestic-scale alkaline fuel cell systems including the development of a continuous carbon dioxide scrubber;
• Investigation into hydrogen and PEM fuel cell systems for remote power supplies, back-up power systems andresidential applications;
• Hydrogen production from renewable sources and from lignite coal via gasification;
• Materials research in the area of reformer and electrolyser catalysts, high-temperature fuel cell electrolytes,hydrogen membrane separators and hydrogen storage materials.

In addition to domestic research,New Zealand is a member of the International Partnership for a Hydrogen Economy and the International Energy Agency (IEA) Hydrogen Implementation Agreement.Although the New Zealand government at the strategic level states “technical issues are likely to prevent hydrogen having anything other than niche uses for the next 25–30 years” (MED, 2007c) research expenditure on the hydrogen economy continues. One of the current research projects involves identifying and overcoming the barriers to implementation of the hydrogen economy in New Zealand (FRST, 2007). Despite policy focus and the significant amount of government expenditure on the hydrogen economy, the benefits of a hydrogen economy to New Zealand have not yet been quantified in any government strategy document or in any of the publications of CRIs. The life cycle assessment of hydrogen compared to electricity has demonstrated that using renewable energy for electric vehicles prevented twice the green house gas emissions as an equivalent hydrogen fuel cell vehicle (Hammerschlag and Mazza, 2005). A thermodynamic analysis of the different concepts for hydrogen generation, transport andstorage by Bossel (2006) unequivocally demonstrates that a hydrogen economy “will never make sense”.

The aim of this paper is to quantitatively examine the operation of the key elements of the energy system for a hydrogen economy within the New Zealand energy context. The hydrogen energy systems proposed in the policy advice document, Energy Scape (CRL Energy Ltd. 2007), will be compared with alternative energy systems. The system analysis will include energy conversion,transmission and energy service demand conversion. The analysis uses either the existing energy infrastructure in New Zealand or a comparable technology model.Hydrogen would be generated through chemical decomposition using some primary energy resource, transported through a distribution system and converted back to electricity to provide an energy service. The key measure of performance for the hydrogen economy is taken as the system-level efficiency, defined as the energy load provided to the end user divided by primary energy resource input.Other potential benefits (such as those listed above) will be discussed, and the utility of the New Zealand governmental expenditure on the hydrogen economy, and future policy directions will be suggested.

Section 2 of this paper describes New Zealand's consumer demand for energy, highlighting the unsustainable and environmental damaging aspects of New Zealand energy consumption. Section 3 describes the hydrogen energy chains that have been proposed for research and development in New Zealand. Section 4 describes the methodology and assumptions used of the energy chain analysis. Section 5 describes the results of the hydrogen energy chain analysis for New Zealand, and the system-level efficiency compared to the existing or an alternative energy system. Additional benefits provided by the hydrogen economy, such as reduced emissions or the ability to store energy, are described on a case by case basis. Section 6 concludes the paper with analysis of policy implications relevant to New Zealand.

dairymanUID: 2683905

氢能源好，这篇简单

lghscuUID: 2552043

解决！

bobo19890313UID: 2622130

还能看懂。。。呵呵