Climate change has been a long-standing issue that continuously drives scientists to find green, sustainable fuels. The universe's most abundant element, hydrogen（氢）, has grabbed their attention and is now on its way to becoming the future of green fuel.

More than $150 billion worth of green hydrogen projects were announced globally in 2020. Airbus, a European multinational aerospace corporation, has taken the lead in the new sustainable fuel industry. It has designed self-contained hydrogen fuel cell pods（燃料电池舱）that can be attached to the underside of airplane wings, promoting the use of hydrogen fuel for long-distance flights, which aim to achieve zero emissions. The company plans to launch hydrogen-powered aircraft in 2035, according to Daily Mail.

Compared to fossil fuels, hydrogen is a much more eco-friendly fuel. When hydrogen burns, the only by-product is water. However, the traditional way to extract（提取）hydrogen from natural gas or coal generates considerable carbon emissions. The greenest way is to obtain hydrogen from water using electrolysis（电解）powered by renewable energy, although this process requires so much electricity that it is quite expensive. The key to making hydrogen competitive with fossil fuels is to lower the production cost to under $1.50. This would require lowering around 50 percent of renewable power costs and 75 percent of electrolyzer costs, according to Australia's renewable energy agency.

Also, shipping liquid hydrogen is challenging, given that needs to be chilled to -253℃ to do so. Japan's Kawasaki Heavy Industries is set to complete the construction of the world's first liquefied hydrogen carrier by early 2021. Most of the world's big hydrogen export projects are looking to ship hydrogen in the form of liquid ammonia（氨）, which can be converted to hydrogen and needs to be chilled to only -33℃.

With more and more countries aiming to cut down carbon emissions to tackle the issue of global warming, green hydrogen will help them hit the targets by decarbonizing industries that cannot be electrified.

"We could use these circumstances, where loads of public money are going to be needed into the energy system, to jump forward towards a hydrogen economy," said Diederik Samsom, the leader of the European Commission's climate cabinet.

【小题1】What do we know about the hydrogen fuel cell pods?

A．They have little by-product.

B．They are inconvenient to carry.

C．They are environmentally friendly.

D．They allow for long-distance flights.

【小题2】What stops hydrogen from being used as widely as fossil fuels?

A．Its lower performance.	B．Its high production cost.
C．Its high carbon emissions.	D．Its complex extracting process.

【小题3】What poses a challenge when shipping liquid hydrogen?

A．The required temperature.

B．The expensive shipping cost.

C．The building of professional carriers.

D．The changing from ammonia to hydrogen.

【小题4】In which industries can green hydrogen play an important role?

A．Those powered by fossil fuels.

B．Those depending on electricity.

C．Those funded by public money.

D．Those with an improved system.